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1.
CEA (Controlled Environment Agriculture) for improving yields and cropping consistency has been discussed by this author for some time now, with the first such article appearing in the September/October edition of Maximum Yield in 2002.
For those of you just tuning in to growing indoors, CEA growing set-ups are “sealed” or “perfect” grow rooms. This means that temperature, humidity and CO2 (carbon dioxide) levels are all very tightly controlled by the grower, and can be maintained at optimal levels at all times for better crop production, regardless of the environmental conditions outside of the growing area. This separates CEA set-ups from traditional in/out style gardens that use an active air intake and exhaust to help moderate the growing environment. While in/out gardens can produce well, they are inconsistent because the environment that can be maintained in the grow room will largely be dependent on the RH (relative humidity) and temperature of the outside air being drawn through the room.
For example, if the outside air in the summer time is 85°F, it will not be very effective for cooling a self-contained growing environment that uses HID (high intensity discharge) lighting. While HIDs can deliver bright light, they generate a tremendous amount of heat that must be managed. Air-cooled lamp reflectors can reduce the cooling requirement of any growing environment, making them a smart investment. However, there will still be some rise in ambient temperature in the grow room, and if outside air is relatively warm to begin with, the grow room will overheat. Overheating in grow room is the number one source of crop failure or disappointing yields for indoor growers.
If you are running centrifugal inline fans for air cooled lamp reflectors, a device like this can really improve the efficiency and operation of your CEA endeavor by continuously adjusting fan speed automatically.
Also, if humidity rises in traditional in/out gardens, the air needs to be exhausted and replaced with outside air. If the RH of the outside air is relatively high, which in most regions is more common than not, the grower loses control over the RH levels in the grow room, leading to poor crop quality and incidence of yield reducing flower and fruit rots, moulds, blights, etc.
Furthermore, increasing CO2 (carbon dioxide) levels in the growing environment can significantly increase yields and reduce cropping time, if properly managed. It is difficult to maintain elevated CO2 levels with in/out gardens because the air is exchanged frequently, if not continuously. The majority of any supplemental CO2 the grower introduces into the in/out grow atmosphere will quickly be exhausted away from the plants when the room is cooling (by exchanging outside air). This reduces the contact time the supplemental CO2 has with the crop, making it less effective if not ineffectual.
Most experienced and knowledgeable growers will maintain that CEA growing set-ups are more productive and easier to work with. A lot of newer growers view the idea of a sealed room with no active in/out fans as alien, and perhaps intimidating. Some smaller and mid-scale experienced growers agree with the CEA concept, but feel that such set-ups are reserved only for the large scale producer due to the additional expense involved versus traditional gardening set-ups.
Well the truth is CEA is more affordable and easier to access than it has ever been before. It can be more economical to upgrade an existing grow room to CEA than it is to create a completely new grow room due to the more frequent, larger and healthier yields that can be achieved. The following will discuss how to setup a hobby sized CEA environment using plug and play technologies available from professional hydroponics retailers or your favorite online sources.
You can also use the information in this article to convert your existing in/out set-up to a more productive and easier to control CEA grow room. Once you make the switch, you won’t look back. Do note, however, that CEA growing environments will use about 25 to 30 per cent more electricity versus traditional in/out set-ups. If electrical consumption is a major concern, there are some very energy efficient cooling methods for sealed environments now available, such as water cooling. Just be prepared for a learning curve and additional installation and trial time when taking advantage of water cooling for the first time. The savings in electrical consumption using water cooling can help to recapture some of the initially higher capital outlay in more energy efficient CEA set-ups.
Remember that the principal difference(s) between CEA and traditional in/out grow rooms is that an air-conditioner or chiller will cool temperatures without exchanging air. Humidity can be lowered with a de-humidifier, which typically cycles more often in the dark cycle as the air conditioner operating during the lighting cycle tends to keep humidity levels in the optimal range. Carbon dioxide is supplied via CO2 generators or bottled CO2, and the air is kept purified and free of contaminants with an activated carbon filter and/or HEPA filter scrubbers. The grower sets the desired temperature, humidity and CO2 levels on their control equipment and the perfect growing environment is maintained everyday, consistently for better harvests year round. The level of control offered is every grower’s dream; you can manipulate the environmental parameters on a weekly basis to help encourage different traits in the crop throughout the cropping cycle. The colorations of flowers and fruits at harvest in a CEA endeavor can be very dramatic and tantalizing.
Step 1: Seal the Room
The growing environment needs to be well sealed in order to be effective and efficient. The easiest way to accomplish this is to purchase a pre-fabricated grow tent or hydro hut; they are available in a multitude of sizes, anywhere from as small as two feet by two feet to beyond 10 feet by 10 feet. Look for manufacturers that have a history of standing behind their product when making a selection. Pre-fabricated grow tents and hydro huts are completely sealable, and usually have multiple zippered openings to contain light and air, while maintaining complete darkness for the dark phase, which is absolutely essential. They are easy to clean and relatively water-proof, allowing people to set-up a high quality grow room in any space that fits without making any significant alterations to existing rooms. You can usually have one completely assembled using minimal or no tools in less than one hour. Note however that they are not well insulated, so the area you set them up in should be, ideally.
If you already have a grow room, make sure to seal up any cracks and leaks. Go through the following checklist:
Environmental Controller(s)
You will need:
Fan speed controllers are also recommended for use with air-cooled lighting and carbon scrubbers. For air-cooled lighting, a high quality fan speed controller will reduce your cooling requirements by more energy intensive equipment such as air-conditioners. The controller featured in this article allows the air-cooled lighting fan(s) to remain at a constant “on” at a speed and decibel pre-set by the grower. If temperatures increase, fan speed increases and vice versa. Also, if the temperature becomes too cool, the device will shut-off the air-cooling fans allowing for the growing environment to maintain the optimal temperature. If you use centrifugal fans for any kind of cooling purposes, get one of these controls!
Carbon Dioxide Gear
One of the benefits of running a CEA grow room is that you can effectively supplement and maintain increased levels of CO2 in the growing environment for faster growth rates and bigger yields. CO2 can increase your yields by as much as 30 per cent, assuming all other growing parameters are optimal, which is achievable in a CEA set-up.
You will need:
Environmental Control
Air Conditioner
The AC or chiller unit is at the heart of all successful CEA operations. ACs are energy intensive, although they can keep a sealed room at the perfect temperature when sized correctly for the number of lamps and other sources of heat like gas fired CO2 generators. The rule of thumb is to allow for about 4500 BTUs of cooling for every 600 to 1000 watts of light. The exact BTU rating required is somewhat dependent on how well the room is insulated; if the ballasts are in the room or not; if air cooled lighting is being used; as well as if a gas fired CO2 generator will be. Again, usually 4500 BTUs is a good rule of thumb. It’s better to get a unit that’s a little bit of overkill than to have a unit that can’t keep up, forcing the grower to shut down individual lamps.
For most hobby sized, one to two light endeavors and a portable upright style AC will do the job and they are relatively inexpensive and easy to find. They are commonly available in 9500 to 12,000 BTU ratings for cooling. They also have the benefit of being able to plug into common 110/120 volt household circuits, although an entire circuit (breaker) should be dedicated to the AC unit.
Most upright portable ACs will use a discharge hose to vent heat away. This means discharging heat to the outside, along with a small volume of air from the grow room. The air volume discharged is relatively small versus fan cooling rooms and cycles on and off rather than constant, so CO2 supplementation still remains relatively efficient. Also, since a carbon or HEPA scrubber operates 24/7 in the growing area, offensive odors are not released to outside of the growing area through the AC discharge. Sometimes growers need to lengthen the hose for discharging warm air away; this will likely void warranties although it can be accomplished with duct booster fans and insulated flexible ducting.
An alternative method to create a small CEA environment is to install a window air conditioner in a spare room. The air in this room is kept cold at all times and can be vented into the CEA growing area to cool the air as necessary via intakes and ducting; the air from the growing area can be vented into the spare room, which now acts as the “lung” for the growing endeavor, keeping it cool and fresh. In these instances you may want to retain the duct ports from your existing grow room.
There are specialty air conditioners available that are better suited to CEA endeavors, although they usually need to be obtained from specialty suppliers. These types of units exchange absolutely no outside air with the air inside of the growing environment. “Split” ACs are an example of this, as well as units that utilize an exclusive air intake and exhaust to the AC unit itself. The intake and exhaust never touch the air from the growing environment; they are used exclusively to keep the AC blowing cold air into the grow room when activated by the cooling thermostat. In this method the AC itself is acting as a sealed unit.
Water cooled ACs are the ultimate for CEA endeavors. All of the heat is discharged down the drain with water, and no hot air needs to be discharged anywhere. Typically a flow rate of 1.5 gallons per minute is required to effectively operate water cooled air-conditioners, so access to large volumes of cold water is required.
However, as stated previously for most small hobby sized CEA endeavors, a portable upright AC is inexpensive, easy to find and relatively efficient.
De-Humidifier
This will help to keep humidity from climbing to excessive levels in a tightly sealed room, as the crop transpires water through the leaves that was absorbed through the roots. Excessive humidity levels encourage stretchy low yielding growth and often promote diseases such as rots and mildews. A de-humidifier will add a bit of heat to the growing environment, and will discharge condensed humidity through a drain hose. You can save this water and use it for other purposes. The de-humidifier is controlled by the de-humidistat, which operates 24/7, although the de-humidifier will cycle most often during the dark cycle when the AC cycles are infrequent. If you use water chillers/fan units to cool the growing environment, you will really need to step-up your de-humidification capabilities. For most applications, count for about 25 to 30 pints per 24 hour period of de-humidification capability per 1000 watt lamp of garden.
Carbon/HEPA Scrubber (with fan)
You may already have one or several of these if you are converting your existing grow to CEA. Otherwise, you will need to size-up an appropriate activated carbon filter or HEPA filter. In fact, the best solution is to use both. Have your fan draw the air from the grow room through the activated carbon, then discharge and re-circulate it through the grow room through a specialty inline HEPA filter. This will keep the air smelling fresh and clean, while reducing insects, spores, dust and pollen in the growing area. This equals healthier air yields, healthier plants and fewer problems. Usually for an area with two to four HID lights, a six inch inline centrifugal fan with the correct sized carbon filter and the six inch fan mount HEPA will keep the air perfectly fresh for you and your garden.
Well, that should give you enough to do between the time you read this article and the continuation that will appear in the next edition of this magazine. Besides, you may already have a crop in progress, and will have to wait until you harvest to make the switch to CEA from your existing in/out growing set-up. Start to take note of which pieces of equipment you already have that can be used to make the upgrade, while researching and sourcing any other controllers, appliances, etc you will require to make the change-over complete and effective.
The extra time and expense that you put into this will be worth it when you are able to realize exacting and complete control over the temperature, humidity and CO2 levels in your growing environment. Not only will you potentially yield more at harvest due to improved CO2 levels, you will be able to bring out delicious and eye pleasing qualities in your plants that can best be achieved through precise temperature manipulation made possible by running a sealed and air conditioned environment. In the next installment we will discuss putting it all together and how to make the most of your modern day CEA growth chamber, including crop feeding, for the biggest and tastiest yields you have ever had. Until next time!
2.
Hello again. If you are just joining us now, in part one of this article we had discussed the benefits of CEA (Controlled Environment Agriculture) grow rooms and the equipment needed to do it. We also touched on the fact that CEA or “sealed” grow rooms aren’t just reserved for the commercial growing elite anymore; equipment is now available for the hobbyist and mid-scale grower that allows for creating the perfect CEA environment, “right out of the box” so to speak.
Now, let’s get down to business and discuss some tips and tricks in setting up the CEA endeavor, how to get the most out of it and we will even talk about nutrients for bigger yields in CEA grow rooms.
Ideally, you will be setting up a pre-fabricated growing enclosure in a customized out of the way spare room. The room that you either use as the grow room or to house your pre-fabricated growing enclosure should be well insulated. If the room is not well insulated, for example windowed areas have not been effectively sealed off, you may experience audible hums and buzzes outside of the growing area. Light leaks from intense light outside of the growing area can be a nuisance and light infiltration during the dark cycle is a serious problem for most flowering plants. Grow tents or hydro huts work great for blocking light; however, they don’t stop much in the way of sound or vibrations. This is why you need to beef-up the insulation in the room housing your grow tent. Heavy gym mats are excellent for dampening vibrations on walls and floors in temporary situations where alterations to the room are kept at a minimum.
Clean, fresh air
When manufacturing the air within a CERA system, cleaner air can be maintained with a combination of inline activated carbon and HEPA filters.
You can either set-up the AC (air-conditioner) directly in the grow tent if it is a portable unit, or if it is a window unit or you are not using a grow tent, you will set-up the AC in the room itself. “Split Unit” ACs are preferred because they do not exchange the air in the grow room, so the additional CO2 (carbon dioxide) that you provide by way of tank and regulator or by gas-fired generator is used more efficiently. Even though the more common types of air-conditioners exchange some level of outside air, they allow for increasing CO2 levels much more efficiently than could be accomplished by intake and exhaust fans in common in/out style gardens.
If you are using a tank and regulator to supplement CO2 levels, you should ensure that the CO2 released is used as efficiently as possible. Replacing CO2 tanks is not inexpensive when you need to do it frequently; plus lugging around the heavy metal cylinders is about as much fun as transporting a missile. In a typical CEA situation that uses air-cooled lighting and a common portable room AC (with discharge hose) a SCUBA sized (20 pound) CO2 tank will last about seven to 10 days. The most important times to have higher than ambient CO2 levels are in mid and late vegetative growth as well as early and mid-flowering (see chart on page 68). CO2 supplementation should be drastically reduced or altogether eliminated in the ripening phase to promote better tastes, stronger and more complex aromas and more intense and vivid colorations.
When installing air-cooled lamp reflectors make sure that they are adequately supported and that hooks, etc. are securely anchored. Having heavy-weight lamp reflectors come crashing down on your plants is dangerous for obvious reasons. Be especially diligent if you live in an area prone to earthquakes; seriously. Typically chains are preferred for hanging heavy weight reflectors, although they are not as easily adjusted as with heavy-duty yo-yo type adjustable light hangers. Having an extra safety chain on each heavy weight lamp reflector is never a bad idea. Remember that “Murphy was an optimist!”
If using water-cooled lighting systems you will have to make sure there is enough support to hold up around 60 pounds per light. A falling water-cooled lighting system could be especially disastrous if the water-cooled lighting system was not being operated with a “no flow, no go” controller (in line with return water supply).
High quality photometrically engineered air-cooled reflectors are perfect for creating a higher level of energy efficiency and CO2 effectiveness when converting an existing in/out grow room into a CEA system. By cutting down on how often your AC cycles to cool the sealed growing environment, you are much further ahead. Water-cooled heat exchangers can also be incorporated into air-cooled lighting fixtures for further efficiency gains and reductions in the heat emitted.
Keeping grow room air fresh and clean while reducing spores and dust is also an important aspect in CEA systems. Since there are little or no air exchanges in CEA systems, the air is “manufactured” by the grower. While this requires equipment and good management practices, it affords the ultimate level of control to deliver the yield levels only capable of next-generation indoor gardens. A carbon filter and HEPA filter combination is the best solution. The air is drawn through the activated carbon in the filter from the grow room by the fan. The fan then blows the filtered air through an inline HEPA filter as it is discharged back into the room again. Very large installations may incorporate a germicidal lamp after the fan in the placement of the system.
Your air filtration system will be much more effective if optimal humidity levels are maintained, for example 50 to 60 per cent RH (relative humidity). In a sealed CEA system this is accomplished in two ways: 1) when the AC cycles it removes moisture from the air, lowering humidity, and 2) by installing the correct sized de-humidifier.
In some environments, it may actually become necessary to install a humidifier to keep humidity levels from going below 40 per cent RH. Either way, both the temperature and humidity need to be controlled. As mentioned in the previous installment, integrated “smart” controllers are a good investment and are more accurate than common household thermostats and de-humidistats. Plus, they work together when incorporated on the same unit, and will not conflict with each other as a result. Units that have remote probes, especially for temperature, are preferred. For optimal results, measure and control the environment in the plant canopy, not the outside walls of the garden.
If you are using bottled CO2, you can save valuable CO2 that can be lost while a portable room type AC (discharge hose) is cycling by plugging your CO2 REG system (regulator, flow meter, solenoid) into a device that “defeats” the CO2 power circuit when the AC comes on. This way, the CO2 dispensed by the more costly tanks does not escape the room, and gets used by the crop. These devices are commonly available at hydroponics suppliers, or can be wired by qualified persons using a relay contact switch.
When using a gas-fired CO2 generator, only infrared monitors and controllers are recommended versus timers, which can be acceptable when using bottled CO2. The output from the monitor that controls the CO2 generator can also be incorporated with a CO2 “defeat” plug, so the gas fired CO2 generator isn’t heating up the room at the same time as the AC is trying to bring temperatures down.
Today growers are very fortunate. In the past, much of the growing gear had to be improvised or custom fabricated. Today growers can purchase tailor made equipment that is ready to use out of the box and that contains detailed instructions for installation and operation. On top of that, when you build it yourself, there is no warranty. Plug and play growing technologies are now cost effective due to their mass appeal versus much of the home-made growing equipment growers were forced to use in the past; making CEA set-ups easier and more productive than ever before.
Now here is some golden information for CEA systems operators. While the inputs will differ slightly from plant variety to plant variety and even from strain to strain, this growing “formula,” that we will call the CEA Map can help anybody who has a well constructed CEA system achieve the next-generation in crop yields.
Once you have the perfect controllable CEA environment, you have the ability to reproduce a growing environment time and time again. While the CEA Map gifted to you above provides a solid foundation, don’t be afraid to experiment. Make sure you record your temperatures, humidity, CO2 and light levels on a daily basis, if possible. This will allow you to look through your records and see what type of environment is giving a particular strain the best results. Also, this way, growers are able to share the data they collect so growing out a new strain can be more akin to following a formula rather than a loosely put together recipe.
As an indoor grower, not only are you fortunate enough to be able to create a laboratory grade CEA system relatively inexpensively and right of the box with plug and play technologies, you also have access to superior crop nutrition versus the fertilizers available to growers in the days of old.
It’s true that plants only need 13 or so basic fertilizer elements to survive, and yes cheap commonly available fertilizers do work to some effect. However, there have been some great advances in crop feeding technologies in the last decade or so, particularly with regards to products formulated for high-output specialty indoor gardening.
There are now complete nutrient packages available that direct growers on a week to week basis for each phase of plant development to deliver the optimal nutrient profile to create peak results in each distinct growth phase. Yes, “feed charts” or “feeding programs” have been available for some time, although they were pieced together over time, in some cases even decades. This means that while the products used might “get along” they really were not engineered looking at the whole picture, rather in fragments. While these programs have served growers relatively well, there is a new generation in what may now be dubbed as “feeding systems.” In these packages, which are designed and available for different grower skill levels, the products used are working synergistically together. This ensures that there is no overlap of active ingredients to create imbalances, and can also ensure the stability and bio-active levels of the nutrient solution they help to create. In fact, some of these nutrient packages are even self pH adjusting, and will work in any type of growing medium due to improvements in nutrient chelation technologies.
Just as CEA systems are and have been the next step in creating the growing atmosphere, specialized nutrient systems containing chelated essential elements, amino acids, wetting agents, fulvates, humates, vitamins, enzymes, carbohydrates, beneficial fungi and even beneficial super bacteria that use pH smart components are the next step in crop feeding technologies.
It seems not much has really changed in the way people grow plants until very recently, thanks to the surge in intensive indoor gardening. In fact, we may be in a renaissance of sorts with regards to crop growth technologies, that will help us to address the growing demands and challenges that lay ahead with our ever expanding population and receding resources. Be proud to be a part of this change, and know that you have the opportunity to be a pioneer in the brave new world of indoor CEA growing.
ja kumam o co chodzi, ale moze komus sie przyda.
CEA (Controlled Environment Agriculture) for improving yields and cropping consistency has been discussed by this author for some time now, with the first such article appearing in the September/October edition of Maximum Yield in 2002.
For those of you just tuning in to growing indoors, CEA growing set-ups are “sealed” or “perfect” grow rooms. This means that temperature, humidity and CO2 (carbon dioxide) levels are all very tightly controlled by the grower, and can be maintained at optimal levels at all times for better crop production, regardless of the environmental conditions outside of the growing area. This separates CEA set-ups from traditional in/out style gardens that use an active air intake and exhaust to help moderate the growing environment. While in/out gardens can produce well, they are inconsistent because the environment that can be maintained in the grow room will largely be dependent on the RH (relative humidity) and temperature of the outside air being drawn through the room.
For example, if the outside air in the summer time is 85°F, it will not be very effective for cooling a self-contained growing environment that uses HID (high intensity discharge) lighting. While HIDs can deliver bright light, they generate a tremendous amount of heat that must be managed. Air-cooled lamp reflectors can reduce the cooling requirement of any growing environment, making them a smart investment. However, there will still be some rise in ambient temperature in the grow room, and if outside air is relatively warm to begin with, the grow room will overheat. Overheating in grow room is the number one source of crop failure or disappointing yields for indoor growers.
Also, if humidity rises in traditional in/out gardens, the air needs to be exhausted and replaced with outside air. If the RH of the outside air is relatively high, which in most regions is more common than not, the grower loses control over the RH levels in the grow room, leading to poor crop quality and incidence of yield reducing flower and fruit rots, moulds, blights, etc.
Furthermore, increasing CO2 (carbon dioxide) levels in the growing environment can significantly increase yields and reduce cropping time, if properly managed. It is difficult to maintain elevated CO2 levels with in/out gardens because the air is exchanged frequently, if not continuously. The majority of any supplemental CO2 the grower introduces into the in/out grow atmosphere will quickly be exhausted away from the plants when the room is cooling (by exchanging outside air). This reduces the contact time the supplemental CO2 has with the crop, making it less effective if not ineffectual.
Most experienced and knowledgeable growers will maintain that CEA growing set-ups are more productive and easier to work with. A lot of newer growers view the idea of a sealed room with no active in/out fans as alien, and perhaps intimidating. Some smaller and mid-scale experienced growers agree with the CEA concept, but feel that such set-ups are reserved only for the large scale producer due to the additional expense involved versus traditional gardening set-ups.
Well the truth is CEA is more affordable and easier to access than it has ever been before. It can be more economical to upgrade an existing grow room to CEA than it is to create a completely new grow room due to the more frequent, larger and healthier yields that can be achieved. The following will discuss how to setup a hobby sized CEA environment using plug and play technologies available from professional hydroponics retailers or your favorite online sources.
You can also use the information in this article to convert your existing in/out set-up to a more productive and easier to control CEA grow room. Once you make the switch, you won’t look back. Do note, however, that CEA growing environments will use about 25 to 30 per cent more electricity versus traditional in/out set-ups. If electrical consumption is a major concern, there are some very energy efficient cooling methods for sealed environments now available, such as water cooling. Just be prepared for a learning curve and additional installation and trial time when taking advantage of water cooling for the first time. The savings in electrical consumption using water cooling can help to recapture some of the initially higher capital outlay in more energy efficient CEA set-ups.
Remember that the principal difference(s) between CEA and traditional in/out grow rooms is that an air-conditioner or chiller will cool temperatures without exchanging air. Humidity can be lowered with a de-humidifier, which typically cycles more often in the dark cycle as the air conditioner operating during the lighting cycle tends to keep humidity levels in the optimal range. Carbon dioxide is supplied via CO2 generators or bottled CO2, and the air is kept purified and free of contaminants with an activated carbon filter and/or HEPA filter scrubbers. The grower sets the desired temperature, humidity and CO2 levels on their control equipment and the perfect growing environment is maintained everyday, consistently for better harvests year round. The level of control offered is every grower’s dream; you can manipulate the environmental parameters on a weekly basis to help encourage different traits in the crop throughout the cropping cycle. The colorations of flowers and fruits at harvest in a CEA endeavor can be very dramatic and tantalizing.
Step 1: Seal the Room
The growing environment needs to be well sealed in order to be effective and efficient. The easiest way to accomplish this is to purchase a pre-fabricated grow tent or hydro hut; they are available in a multitude of sizes, anywhere from as small as two feet by two feet to beyond 10 feet by 10 feet. Look for manufacturers that have a history of standing behind their product when making a selection. Pre-fabricated grow tents and hydro huts are completely sealable, and usually have multiple zippered openings to contain light and air, while maintaining complete darkness for the dark phase, which is absolutely essential. They are easy to clean and relatively water-proof, allowing people to set-up a high quality grow room in any space that fits without making any significant alterations to existing rooms. You can usually have one completely assembled using minimal or no tools in less than one hour. Note however that they are not well insulated, so the area you set them up in should be, ideally.
If you already have a grow room, make sure to seal up any cracks and leaks. Go through the following checklist:
- Remove and seal off previous intake and exhaust ports, you may choose to keep them for use with air-cooled lighting however.
- Seal off any cracks with expanding foam, available in cans. Make sure to wear gloves and old clothes when applying.
- Ensure that any duct work, i.e. air cooled reflectors, is well sealed using aluminum tape.
- Make sure that the doorway does not leak air. This can be accomplished by using a sheet of durable and reflective poly sheeting with some heavy duty adhesive zippers or Velcro strips.
- Retain your carbon filter and fan; you will need this for “scrubbing” the air within the CEA growing set up.
- Ensure that the grow room itself is well insulated to improve efficiency and reduce noises that can be disturbing outside of the growing area.
Environmental Controller(s)
You will need:
- cooling thermostat
- de-humidistat
- high temperature kill-switch
Fan speed controllers are also recommended for use with air-cooled lighting and carbon scrubbers. For air-cooled lighting, a high quality fan speed controller will reduce your cooling requirements by more energy intensive equipment such as air-conditioners. The controller featured in this article allows the air-cooled lighting fan(s) to remain at a constant “on” at a speed and decibel pre-set by the grower. If temperatures increase, fan speed increases and vice versa. Also, if the temperature becomes too cool, the device will shut-off the air-cooling fans allowing for the growing environment to maintain the optimal temperature. If you use centrifugal fans for any kind of cooling purposes, get one of these controls!
Carbon Dioxide Gear
One of the benefits of running a CEA grow room is that you can effectively supplement and maintain increased levels of CO2 in the growing environment for faster growth rates and bigger yields. CO2 can increase your yields by as much as 30 per cent, assuming all other growing parameters are optimal, which is achievable in a CEA set-up.
You will need:
- either a CO2 generator (propane/natural gas) or a tank (bottled CO2)
- an infrared CO2 monitor/controller (pricey, but worth it) or a timer.
Environmental Control
Air Conditioner
The AC or chiller unit is at the heart of all successful CEA operations. ACs are energy intensive, although they can keep a sealed room at the perfect temperature when sized correctly for the number of lamps and other sources of heat like gas fired CO2 generators. The rule of thumb is to allow for about 4500 BTUs of cooling for every 600 to 1000 watts of light. The exact BTU rating required is somewhat dependent on how well the room is insulated; if the ballasts are in the room or not; if air cooled lighting is being used; as well as if a gas fired CO2 generator will be. Again, usually 4500 BTUs is a good rule of thumb. It’s better to get a unit that’s a little bit of overkill than to have a unit that can’t keep up, forcing the grower to shut down individual lamps.
For most hobby sized, one to two light endeavors and a portable upright style AC will do the job and they are relatively inexpensive and easy to find. They are commonly available in 9500 to 12,000 BTU ratings for cooling. They also have the benefit of being able to plug into common 110/120 volt household circuits, although an entire circuit (breaker) should be dedicated to the AC unit.
Most upright portable ACs will use a discharge hose to vent heat away. This means discharging heat to the outside, along with a small volume of air from the grow room. The air volume discharged is relatively small versus fan cooling rooms and cycles on and off rather than constant, so CO2 supplementation still remains relatively efficient. Also, since a carbon or HEPA scrubber operates 24/7 in the growing area, offensive odors are not released to outside of the growing area through the AC discharge. Sometimes growers need to lengthen the hose for discharging warm air away; this will likely void warranties although it can be accomplished with duct booster fans and insulated flexible ducting.
An alternative method to create a small CEA environment is to install a window air conditioner in a spare room. The air in this room is kept cold at all times and can be vented into the CEA growing area to cool the air as necessary via intakes and ducting; the air from the growing area can be vented into the spare room, which now acts as the “lung” for the growing endeavor, keeping it cool and fresh. In these instances you may want to retain the duct ports from your existing grow room.
There are specialty air conditioners available that are better suited to CEA endeavors, although they usually need to be obtained from specialty suppliers. These types of units exchange absolutely no outside air with the air inside of the growing environment. “Split” ACs are an example of this, as well as units that utilize an exclusive air intake and exhaust to the AC unit itself. The intake and exhaust never touch the air from the growing environment; they are used exclusively to keep the AC blowing cold air into the grow room when activated by the cooling thermostat. In this method the AC itself is acting as a sealed unit.
Water cooled ACs are the ultimate for CEA endeavors. All of the heat is discharged down the drain with water, and no hot air needs to be discharged anywhere. Typically a flow rate of 1.5 gallons per minute is required to effectively operate water cooled air-conditioners, so access to large volumes of cold water is required.
However, as stated previously for most small hobby sized CEA endeavors, a portable upright AC is inexpensive, easy to find and relatively efficient.
De-Humidifier
This will help to keep humidity from climbing to excessive levels in a tightly sealed room, as the crop transpires water through the leaves that was absorbed through the roots. Excessive humidity levels encourage stretchy low yielding growth and often promote diseases such as rots and mildews. A de-humidifier will add a bit of heat to the growing environment, and will discharge condensed humidity through a drain hose. You can save this water and use it for other purposes. The de-humidifier is controlled by the de-humidistat, which operates 24/7, although the de-humidifier will cycle most often during the dark cycle when the AC cycles are infrequent. If you use water chillers/fan units to cool the growing environment, you will really need to step-up your de-humidification capabilities. For most applications, count for about 25 to 30 pints per 24 hour period of de-humidification capability per 1000 watt lamp of garden.
Carbon/HEPA Scrubber (with fan)
You may already have one or several of these if you are converting your existing grow to CEA. Otherwise, you will need to size-up an appropriate activated carbon filter or HEPA filter. In fact, the best solution is to use both. Have your fan draw the air from the grow room through the activated carbon, then discharge and re-circulate it through the grow room through a specialty inline HEPA filter. This will keep the air smelling fresh and clean, while reducing insects, spores, dust and pollen in the growing area. This equals healthier air yields, healthier plants and fewer problems. Usually for an area with two to four HID lights, a six inch inline centrifugal fan with the correct sized carbon filter and the six inch fan mount HEPA will keep the air perfectly fresh for you and your garden.
Well, that should give you enough to do between the time you read this article and the continuation that will appear in the next edition of this magazine. Besides, you may already have a crop in progress, and will have to wait until you harvest to make the switch to CEA from your existing in/out growing set-up. Start to take note of which pieces of equipment you already have that can be used to make the upgrade, while researching and sourcing any other controllers, appliances, etc you will require to make the change-over complete and effective.
The extra time and expense that you put into this will be worth it when you are able to realize exacting and complete control over the temperature, humidity and CO2 levels in your growing environment. Not only will you potentially yield more at harvest due to improved CO2 levels, you will be able to bring out delicious and eye pleasing qualities in your plants that can best be achieved through precise temperature manipulation made possible by running a sealed and air conditioned environment. In the next installment we will discuss putting it all together and how to make the most of your modern day CEA growth chamber, including crop feeding, for the biggest and tastiest yields you have ever had. Until next time!
2.
Hello again. If you are just joining us now, in part one of this article we had discussed the benefits of CEA (Controlled Environment Agriculture) grow rooms and the equipment needed to do it. We also touched on the fact that CEA or “sealed” grow rooms aren’t just reserved for the commercial growing elite anymore; equipment is now available for the hobbyist and mid-scale grower that allows for creating the perfect CEA environment, “right out of the box” so to speak.
Now, let’s get down to business and discuss some tips and tricks in setting up the CEA endeavor, how to get the most out of it and we will even talk about nutrients for bigger yields in CEA grow rooms.
Ideally, you will be setting up a pre-fabricated growing enclosure in a customized out of the way spare room. The room that you either use as the grow room or to house your pre-fabricated growing enclosure should be well insulated. If the room is not well insulated, for example windowed areas have not been effectively sealed off, you may experience audible hums and buzzes outside of the growing area. Light leaks from intense light outside of the growing area can be a nuisance and light infiltration during the dark cycle is a serious problem for most flowering plants. Grow tents or hydro huts work great for blocking light; however, they don’t stop much in the way of sound or vibrations. This is why you need to beef-up the insulation in the room housing your grow tent. Heavy gym mats are excellent for dampening vibrations on walls and floors in temporary situations where alterations to the room are kept at a minimum.
When manufacturing the air within a CERA system, cleaner air can be maintained with a combination of inline activated carbon and HEPA filters.
You can either set-up the AC (air-conditioner) directly in the grow tent if it is a portable unit, or if it is a window unit or you are not using a grow tent, you will set-up the AC in the room itself. “Split Unit” ACs are preferred because they do not exchange the air in the grow room, so the additional CO2 (carbon dioxide) that you provide by way of tank and regulator or by gas-fired generator is used more efficiently. Even though the more common types of air-conditioners exchange some level of outside air, they allow for increasing CO2 levels much more efficiently than could be accomplished by intake and exhaust fans in common in/out style gardens.
If you are using a tank and regulator to supplement CO2 levels, you should ensure that the CO2 released is used as efficiently as possible. Replacing CO2 tanks is not inexpensive when you need to do it frequently; plus lugging around the heavy metal cylinders is about as much fun as transporting a missile. In a typical CEA situation that uses air-cooled lighting and a common portable room AC (with discharge hose) a SCUBA sized (20 pound) CO2 tank will last about seven to 10 days. The most important times to have higher than ambient CO2 levels are in mid and late vegetative growth as well as early and mid-flowering (see chart on page 68). CO2 supplementation should be drastically reduced or altogether eliminated in the ripening phase to promote better tastes, stronger and more complex aromas and more intense and vivid colorations.
When installing air-cooled lamp reflectors make sure that they are adequately supported and that hooks, etc. are securely anchored. Having heavy-weight lamp reflectors come crashing down on your plants is dangerous for obvious reasons. Be especially diligent if you live in an area prone to earthquakes; seriously. Typically chains are preferred for hanging heavy weight reflectors, although they are not as easily adjusted as with heavy-duty yo-yo type adjustable light hangers. Having an extra safety chain on each heavy weight lamp reflector is never a bad idea. Remember that “Murphy was an optimist!”
If using water-cooled lighting systems you will have to make sure there is enough support to hold up around 60 pounds per light. A falling water-cooled lighting system could be especially disastrous if the water-cooled lighting system was not being operated with a “no flow, no go” controller (in line with return water supply).
High quality photometrically engineered air-cooled reflectors are perfect for creating a higher level of energy efficiency and CO2 effectiveness when converting an existing in/out grow room into a CEA system. By cutting down on how often your AC cycles to cool the sealed growing environment, you are much further ahead. Water-cooled heat exchangers can also be incorporated into air-cooled lighting fixtures for further efficiency gains and reductions in the heat emitted.
Keeping grow room air fresh and clean while reducing spores and dust is also an important aspect in CEA systems. Since there are little or no air exchanges in CEA systems, the air is “manufactured” by the grower. While this requires equipment and good management practices, it affords the ultimate level of control to deliver the yield levels only capable of next-generation indoor gardens. A carbon filter and HEPA filter combination is the best solution. The air is drawn through the activated carbon in the filter from the grow room by the fan. The fan then blows the filtered air through an inline HEPA filter as it is discharged back into the room again. Very large installations may incorporate a germicidal lamp after the fan in the placement of the system.
Your air filtration system will be much more effective if optimal humidity levels are maintained, for example 50 to 60 per cent RH (relative humidity). In a sealed CEA system this is accomplished in two ways: 1) when the AC cycles it removes moisture from the air, lowering humidity, and 2) by installing the correct sized de-humidifier.
In some environments, it may actually become necessary to install a humidifier to keep humidity levels from going below 40 per cent RH. Either way, both the temperature and humidity need to be controlled. As mentioned in the previous installment, integrated “smart” controllers are a good investment and are more accurate than common household thermostats and de-humidistats. Plus, they work together when incorporated on the same unit, and will not conflict with each other as a result. Units that have remote probes, especially for temperature, are preferred. For optimal results, measure and control the environment in the plant canopy, not the outside walls of the garden.
If you are using bottled CO2, you can save valuable CO2 that can be lost while a portable room type AC (discharge hose) is cycling by plugging your CO2 REG system (regulator, flow meter, solenoid) into a device that “defeats” the CO2 power circuit when the AC comes on. This way, the CO2 dispensed by the more costly tanks does not escape the room, and gets used by the crop. These devices are commonly available at hydroponics suppliers, or can be wired by qualified persons using a relay contact switch.
When using a gas-fired CO2 generator, only infrared monitors and controllers are recommended versus timers, which can be acceptable when using bottled CO2. The output from the monitor that controls the CO2 generator can also be incorporated with a CO2 “defeat” plug, so the gas fired CO2 generator isn’t heating up the room at the same time as the AC is trying to bring temperatures down.
Today growers are very fortunate. In the past, much of the growing gear had to be improvised or custom fabricated. Today growers can purchase tailor made equipment that is ready to use out of the box and that contains detailed instructions for installation and operation. On top of that, when you build it yourself, there is no warranty. Plug and play growing technologies are now cost effective due to their mass appeal versus much of the home-made growing equipment growers were forced to use in the past; making CEA set-ups easier and more productive than ever before.
Now here is some golden information for CEA systems operators. While the inputs will differ slightly from plant variety to plant variety and even from strain to strain, this growing “formula,” that we will call the CEA Map can help anybody who has a well constructed CEA system achieve the next-generation in crop yields.
Once you have the perfect controllable CEA environment, you have the ability to reproduce a growing environment time and time again. While the CEA Map gifted to you above provides a solid foundation, don’t be afraid to experiment. Make sure you record your temperatures, humidity, CO2 and light levels on a daily basis, if possible. This will allow you to look through your records and see what type of environment is giving a particular strain the best results. Also, this way, growers are able to share the data they collect so growing out a new strain can be more akin to following a formula rather than a loosely put together recipe.
As an indoor grower, not only are you fortunate enough to be able to create a laboratory grade CEA system relatively inexpensively and right of the box with plug and play technologies, you also have access to superior crop nutrition versus the fertilizers available to growers in the days of old.
It’s true that plants only need 13 or so basic fertilizer elements to survive, and yes cheap commonly available fertilizers do work to some effect. However, there have been some great advances in crop feeding technologies in the last decade or so, particularly with regards to products formulated for high-output specialty indoor gardening.
There are now complete nutrient packages available that direct growers on a week to week basis for each phase of plant development to deliver the optimal nutrient profile to create peak results in each distinct growth phase. Yes, “feed charts” or “feeding programs” have been available for some time, although they were pieced together over time, in some cases even decades. This means that while the products used might “get along” they really were not engineered looking at the whole picture, rather in fragments. While these programs have served growers relatively well, there is a new generation in what may now be dubbed as “feeding systems.” In these packages, which are designed and available for different grower skill levels, the products used are working synergistically together. This ensures that there is no overlap of active ingredients to create imbalances, and can also ensure the stability and bio-active levels of the nutrient solution they help to create. In fact, some of these nutrient packages are even self pH adjusting, and will work in any type of growing medium due to improvements in nutrient chelation technologies.
Just as CEA systems are and have been the next step in creating the growing atmosphere, specialized nutrient systems containing chelated essential elements, amino acids, wetting agents, fulvates, humates, vitamins, enzymes, carbohydrates, beneficial fungi and even beneficial super bacteria that use pH smart components are the next step in crop feeding technologies.
It seems not much has really changed in the way people grow plants until very recently, thanks to the surge in intensive indoor gardening. In fact, we may be in a renaissance of sorts with regards to crop growth technologies, that will help us to address the growing demands and challenges that lay ahead with our ever expanding population and receding resources. Be proud to be a part of this change, and know that you have the opportunity to be a pioneer in the brave new world of indoor CEA growing.
ja kumam o co chodzi, ale moze komus sie przyda.
