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Closed Loop Horticulture (Closed Environment Agriculture)

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Closed Loop Horticulture (Closed Environment Agriculture)

Merging Nature and Technology Even Closer Together – Closed Loop Horticulture

This method is also known as: Closed Growing Environment (CGE), Sealed Room, Closed Loop Environment or the Perfect Room.

Esoteric Hydroponics are proud to announce that due to demand, we are now specialising in what is clearly becoming the next level of indoor horticulture techniques, and are now fully stocked and selling the best products available on the market for creating the perfect closed environment grow room. Closed rooms are used by the best commercial growers for large scale applications. But can easily be down sized for the enthusiast and hobby grower as well. There is no better way to grow, and you will be asking yourself why you didn't convert sooner, when you realise how much easier your gardening life becomes.

If you are tired of temperature spikes in the hot days of summer, tired of having to heat or have cold periods during the days of winter, frustrated with going through endless bottles of CO2, or furious with having to tackle various pests, spores, moulds and airborne diseases finding their way into your grow room and attacking your beloved plants, then read this article, follow our advice and join the rapidly growing movement which is simply the future and next level of indoor growing methods.

Traditional grow rooms here in the UK and across the globe have for many years been a fairly basic concept. Running numbers of HID light fixtures in a confined space to mimic the intense light of the sun, coupled with powerful intake and extraction fans to combat the massive amounts of heat generated by the lamps and ballasts and other equipment in your room, whilst also allowing fresh air to flow through the room providing your plants with CO2 and oxygen, this is the basic concept of a traditional grow room. However, this concept is flawed. All indoor growers that know what they are doing are all basically aiming for the same ideals: optimal temperature ranges between 22-28 degrees centigrade, optimal humidity levels of approximately 50% - 65% when in the blooming stage of growth, depending on plant species, and as little to no temperature and humidity fluctuations as possible. But what do you do when the temperature outside is higher than the desired levels within your grow room? Or when it's particularly humid outside? You sit there scratching your head, and basically pray that the temperature or humidity levels drop before too much damage is done to your crop. What we are getting at here is the entire concept of the traditional grow room which has been practiced and built upon for all these years, all around the world, is fundamentally flawed, because despite the money you spend on massive loud extraction fan systems, environmental controllers and everything else in between, the outside conditions are always dictating the conditions within your grow room, If it's 25°C outside, then it is literally impossible to maintain the desired temperature within your grow room. And there is only one answer to solving these problems, whilst having absolute control of every aspect of your indoor grow room, 24 hours a day, 365 days a year. That answer is; pull down those fans, get rid of that messy ducting, seal up all of those holes and create a totally perfect closed off grow room - create your very own garden of Eden: A CLOSED GROWING ENVIRONMENT!

A Closed Growing Environment is an indoor garden that is totally … you've guessed it … closed! And we aren't just talking about light proofing here. We mean air-sealed. There are no holes, gaps or vents to anything outside of the indoor garden. The name of the game here is to create a totally controlled environment where every aspect of the plants' production can be manipulated and customized to produce the optimum results. Setting up a closed indoor garden is more expensive but, if done correctly, it should give you the maximum ability to dictate and control temperatures, CO2 levels, humidity and disease - 24 hours a day, 365 days a year and generally most people who make the change and do it thoroughly and correctly report massive increased yields and far less pest problems.

I bet at this point, some of you are scratching your swede and thinking to yourself, "if I totally seal off my room and exchange no air through extraction, isn't my room going to get really, really hot and my plants suffocate to death through lack of fresh air?" This is where the three main parts to a closed room come into play. The three central organs of a closed grow room are: air conditioners, dehumidifiers and CO2 generators. With these three items replacing your fans, you can have a perfect room, plain and simple.

Now let's break it down. Firstly, air conditioning. There are many types of air conditioners available - portable units, both single hosed and dual hosed, window units, commercial sized spot coolers and more. All of these will provide some cooling power, but unfortunately these units tend to be inefficient and most types actually use air from within your room to cool the internal compressor and this totally defeats the object of keeping the room sealed, as they will be sucking some air out of your room which will create a negative air pressure within your room and will waste precious CO2. The only units we would advise using, which we stock, are split air conditioners and water cooled air conditioners, A split air conditioner exchanges no air with the outside world, they are, as their name would suggest, split, into two units, an indoor air handler, and an outdoor condenser unit with a pre-charged and sealed umbilical line which can be installed without the help of a qualified expert. These units are the best available, from lighter mini splits, all the way to commercial units that can cool 24 600 watt lights, are guaranteed for easy do-it-yourself installation. In simple terms, the indoor air handler would be placed within the grow room, it will pull air from within the grow room across a heat exchanger with incredibly cold refrigerant running through it, and the heat within the air is then transferred down the tubing through the refrigerant to the outdoor unit where the heat is expelled. So, no air is being removed from the room, only the heat within the air is removed before the air is blown straight back to the grow room. Likewise, water cooled air conditioners can be self-installed and are very efficient in terms of power usage, and can transfer heat very efficiently and send it down the drain into the sewers, they do not require an outdoor condenser, which will be appealing for a lot of situations, but the downside to water cooled units are they will use incredible amounts of water so if you’re on a metered water supply it’s not advisable.

Another added bonus of using air conditioning in a closed room is the benefit of dehumidification; the air conditioner not only cools but also dehumidifies as it cools, and in a sealed off room as your plants transpire, there will be an abundance of humidity created, which for the most part can be perfectly controlled with your air conditioner. Now Air conditioners are rated in BTU's (British Thermal Units). This represents how many BTU's of heat they can cool per hour. They can also be rated in tons and Killer-watts, the basic rule is simple 12000 BTU's is the equivalent to 1 ton of air conditioning which is 3.52 killer-watts, so to calculate cooling requirements all we need to do is calculate how many watts of heat we need to cool per hour, 1000 watts of light is generating 3412 BTU's of heat, Now there are several methods of calculating Air con size for closed rooms, But only applicable when using the proper, made for the job systems that we stock. This is tried and tested, 1000 watts of power, is 1000 watts, bulb and ballast combined, regardless of the bulb or ballasts efficiency. Combined they are generating 3412 BTU's of heat, in the case of an old magnetic core and coil ballast the light generated may be less efficient and the ballast producing more heat, but combined they are still 1000 watts and still creating 3412 BTU's of heat. A modern digital ballast has a much more efficient way of operating creating a brighter more efficient burn of the same lamp, resulting in a hotter bulb, but a cooler ballast, but combined, they are still generating 3412 BTU's of heat. With all of this in mind, we must allow 4000 BTU's of cooling power, per 1000 watts of light, this allows for the room size and CO2 burners, the heat from Dehumidifiers should also be factored in, if a dehumidifier consumes 700 watts of power, it is producing 700 x 3.41 BTU’s of heat or 2387 BTU’s. One ton (12000) BTU's of cooling power for every 3000 watts of light plus the extra bit for your dehumidification will give you the correct amount of cooling. These calculations can be downsized by 10 percent if ballasts are placed outside the grow space, and by another 20 percent approximately if the lights are air cooled. But since not all appliances are 100 percent efficient we should also factor in maybe 20 percent extra power to play it safe and account for other variables like outside temps, or how well insulated your room is and also allowing our air con, to not have to run at 100 percent all day long, prolonging the life of the units and components within it. So when sizing your Air con, just remember to allow 4000 BTU's of cooling power for every 1000 watts of lighting or 2400 BTU's for every 600 watts of lighting, and 3.41 BTU’s per watt of the power of your Dehumidification. And up the total by 15 – 20 %. Only expect these calculations to work if your using quality Air con units, some are far less efficient than others.

The second thing we have begun to tackle but not entirely is humidity. While air conditioners are dehumidifying to some degree, they are doing so as a Bi-product of the way in which they function in order to cool the air. So when the lights come on or go off with only an air conditioner in the room, you will have massive spikes in humidity, as the air con ceases to need to cool the lights to maintain the desired temperature. When the lights go off, it will also stop dehumidifying, and since the room is sealed with no ventilation, the humidity will rapidly climb to 100%. due to transpiration and evaporation and more importantly, the environmental change in the room, as the lights shut down, the hot air in the room while the lights are on can hold much more water than it can when the temperature drops at the end of the light cycle, at this point, the water held in the air will suddenly have nowhere to go and humidity will rapidly climb and condensation will settle everywhere including your plants. This is why we would employ a dehumidifier which will automatically kick on and off as required to maintain the desired level of humidity within the room, 24 hours a day. Now, there are rules in sizing a dehumidifier just as there are in sizing your air conditioner and as far as sizing the dehumidification volume of your dehumidifier is concerned, we recommend approximately 1 litre per plant per 24 hour period.  It is very important to understand, Dehumidifier water removal ratings are generally based on how many litres of water they can remove per 24 hour period. However they are almost always tested for 32 degrees centigrade and 80 percent relative humidity, when you drop the temperature to ideal growing conditions of 24 - 28 degrees, the water collection rate will drop significantly. We have listed all of our Dehumidifiers at how much they can actually remove in grow-room conditions. We recommend maintaining an even temperature through the night cycle also, for this is when your dehumidifier will be under the most strain, and the lower the room temperature gets the bigger drop in dehumidification performance you will see, and studies have shown, that  plants perform very well with little to no temperature drop at night. The reason we need such powerful dehumidification in a room of this type is this. A large mature plant in a hydroponic system can consume up to a litre of water per day., very large plants, can drink even more, and almost all of the water consumed by a plant will enter back into the atmosphere of the room through transpiration, and other variables such as evaporation from tanks and water vapour created by your CO2 generators all add up. It is quite difficult to come up with a precise equation for calculating your dehumidifier requirements, but we have always found it better to oversize these things than to undersize, so a good rule of thumb when sizing a dehumidifier for a closed room environment is to allow 1 litre of dehumidification per plant or more, If unsure always oversize to be safe. We also advise for the earlier stages of plant development in a closed room, that growers employ humidifiers, the reason being is that very young plants in a sealed room will not be transpiring very much water into the atmosphere of the room, and with your air conditioners and dehumidifiers running, you can end up with lower than desired levels of humidity. This will only be an issue in the very early stages of plant development, and once the plants begin to grow rapidly and establish, in most scenario's humidifiers will no longer be necessary.

One more subject to briefly touch upon while on the subject of humidity in closed room environments, is the massive benefit of the availability of pure clean distilled water, also known as Reverse osmosis water (R.O water) as your air conditioners and dehumidifiers are collecting condensation from the air, instead of wasting this essentially pure water down the drain you can collect it and use it to top up your tanks. You can literally create your own micro climate, or eco system. Recycling the same water, being fed through the plants and transpired into the atmosphere of your room and then dehumidified and collected back into your tanks and fed back to the plants again, over and over, Eliminating the need to use contaminated tap water, full of chlorine and sodium fluoride and who knows what else, And not having to run hoses to your tanks all the time.

The final vital components of a sealed off grow room are CO2 and oxygen. Many growers believe that plants need to have fresh air in order to survive; in actual fact plants only require two components of what fresh air contains, and these are oxygen and CO2. Firstly, we highly advise the use of air pumps installed high up in the grow room blowing small amounts of fresh air directly into the reservoirs and root balls of the plants. in a sealed room that is full of CO2, the roots of your plants will have a hard time finding oxygen if the air pumps are mounted at ground level, this is why it is very important in any closed room situation to keep the air pump mounted high in the grow space, because if it is placed low down, you will be blowing CO2 into the roots, not oxygen, which will have an extremely detrimental effect on the plants. Aeration to the roots of plants is one of the most overlooked things in horticulture and keeping the roots constantly aerated will boost the performance of any plant to other levels. At the same time making it very difficult for disease to find its way into your water as it will remain rich in oxygen, especially when kept down to optimal temps of 65F/18C. We do NOT advise growing in soil if you’re running a sealed room, roots have a hard enough time finding oxygen in soil as it is, but in a sealed room, without a super aerated hydroponic system, a plant in soil will just not have the oxygen levels required to produce bumper yields.

Next, let's take a look at CO2 levels. Growers all know that plants need CO2 in order to photosynthesize, so we're going to supply this if we're not relying on fresh air ventilation. Growers using standard ventilation can maintain normal atmospheric levels of CO2 in their indoor gardens. If they wish to add more to try and boost growth however, they often encounter a dilemma. What's the point of injecting extra CO2 into your indoor growing environment if it's going to be vented out again before your plants have had a chance to benefit from it? High energy plants in optimum lighting conditions of approximately 10,000 lumens per square foot can happily consume 1,200 to 1,500 parts per million (ppm) of CO2. The outside air we breathe contains approximately 400 ppm, so in basic terms, you can double the growth rate and productivity of a plant by supplying it with the levels of CO2 it requires to be able to harness the massive levels of light we are giving it. Whilst on this subject, there have been studies that are not very well known by many growers around the world, concerning CO2 uptake in high energy plants, you can overdo it, and many, many people actually are over doing it, consistently. When you take CO2 levels in a grow space past a level of 1500 ppm, in most species, the stomata on the underside of the leaf which absorb the CO2, actually start to close up and from that level of 1500 ppm and higher, the further you push the levels, the less and less efficiently the plant will grow, so we advise maintaining the levels, between, 1200 to 1400 ppm for optimum growth rates. Likewise another quick tip for all you closed roomers out there, when using CO2 do NOT believe the hype about raising the temps in your room to silly levels like 90F/32C, expecting improved results, while plants can tolerate higher temps in a CO2 enriched environment, it does not mean they perform better at all, certain species will benefit from a slightly raised temperature and humidity level when exposed to optimal co2 levels, we recommend 26 – 28 degrees centigrade and 60 – 65% relative humidity during flower, but only in certain situations and not always, but don’t push it any higher if you can avoid it. We advise the use of CO2 generators which can produce massive amounts of CO2 by burning LPG propane gas, which is easily available and cheap. These types of generators have an electric ignition so there is no pilot light to be worried about. Some models have water cooling options, you then plug the generator into an infrared CO2 monitoring device with a photo sensor which will perfectly regulate the CO2 levels in the room while the lights are on, and will shut off the CO2 when the lights are off. Trying to guess it with older CO2 dosing equipment, may work, but is not advisable, all equipment in a perfect closed room should be running from sensors to monitor air and other factors to ensure an ideal growing environment: 75-85F (24-28C) temperature, 50% - 65% humidity, 1,200 - 1,400 ppm CO2, constant air movement and aeration, and scrubbed air. Some sensors can be equipped with remote monitoring and notification features so that growers are notified by pager/mobile phone if their grow room environment has slipped out of optimum growing parameters. When combined with computerised interface and cross-links to security systems, growers can instantly find out what's happening to their grow room from almost anywhere in the world. Now, as with sizing up the air con and dehumidification requirements, there is a rough rule of thumb to sizing up a CO2 generator as well. The higher the rating of the Generator, the faster it will fill a given space with the set level of CO2, Generators are usually rated in how many cubic feet of CO2 they can produce per hour, usually each individual burner in the co2 generator will produce approximately 3 cubic feet of co2, we have found that a 4 burner tends to suit an area of up to 15ft x 15ft and an 8 burner covers 25ft x 25ft. Sometimes they are rated in  killer-watts (Kw) an 8kw generator is good for about 150 square feet, a 16kw is good for about 300 square feet, and so on. Burning LPG to create CO2 will produce some heat but this can all be accounted for if we remember to always allow 4000 BTU's of cooling power for every 1000 watts of HID light. Or if burning gas is not for you… you can simply fit a normal CO2 bottle and regulator to one of our CO2 sensors, set the ppm you require and the rest is easy. Also, the use of bottled CO2 can facilitate the killing of spider mites and other pests. In true sealed grow rooms that have no leaks, growers can kill all pests by upping CO2 levels to 10,000 ppm for one hour. Other CO2 augmentation methods are incapable of generating 10,000 ppm for an hour. Only the bottle supply method is capable of providing that concentration of CO2. In particular, when using 10,000 ppm bug-killing tactics, growers must use safety methods that minimise the health problems that CO2 can cause to humans. So these are the vital components within the fresh air which your plants require sorted.

Another thing to mention is pests and disease, airborne or otherwise. Nothing can get into your room to cause your plants harm, as there is no way into your room. Unwanted heat and odours will not be expelled from the room either. We highly recommend running ozone generators to combat any spores or fungi that could occur within the sealed space and to utilise some blue light throughout the entire growth cycle. Metal halides and daylight lamps are abundant in UV light which whilst causing no harm to your plants, actually benefits them in many ways and will also keep at bay things like powdery mildew and botrytis. The larger commercial grade air con units we stock can be fitted with UV air cleaners to ensure there are 0 spores or contaminants in the air at all times.

The Use of Activated Carbon filters (scrubbers) should always be used in a sealed grow space, place your filter wherever you like in the room, attach an inline fan of the correct size to it, and just have it on 24 hours a day, pulling air through the filter and blowing back into the room again, this creates no positive or negative pressure and you are not exhausting any air, you are literally just scrubbing it clean of any unwanted air-borne contaminants and helping to control odours. We suggest placing the filter on the floor as this helps to mix any unused CO2, which is heavier than air, back to the top of the room, to fall back on to your plants.

With all the previously mentioned items in conjunction with hydroponic systems and lighting systems, we can help you create a room which can easily be kept at the exact levels of temperature, humidity and CO2 required to make your plants go absolutely bonkers 365 days a year, seriously, you will not believe the results that are achievable, no matter what the outside conditions may be. And once you get your head around the concept of closed environment growing, it really is a simpler way to do things, because you are relieving yourself of so many problems that growers have been combating for so many years.

Now, lastly, after 3 years of helping people with sealed set ups, gaining feedback and troubleshooting various problems we have discovered a few valuable things which we would like to share with you all, firstly, make sure you buy quality air-conditioning if your running anything larger than a small hobby sized set up, cheap ones underperform and eventually break, also, when your lights are off it is good practice, however not an absolute necessity, to run a very small amount of ventilation, it is not always needed but can help a lot in some situations, to refresh just a tiny bit of air in the room between light cycles, it will help to avoid co2 getting too high during the night, it will also give a slightly negative room pressure which will assist the stomata in staying open and ready for co2 absorption when the lights come back on, it will also evacuate any mild levels of toxicity from co2 burners that may build up in the room and will also assist in a bit of extra oxygen for the root system, but we must firmly state, we mean tiny levels of extraction, like a 100mm RVK fan and filter is all that is necessary. We have had a lot of feedback from many people also claiming that to drop the co2 back to atmospheric levels for the last week or two during flush has a very positive effect on the end product resulting in a much higher quality crop, we recommend this whole heartedly. And the last thing we cannot emphasise enough, is that you do a very thorough job of insulating and sealing your room, the more well insulated you are, the more effectively and efficiently the room will run, and use lots of air movement and circulation fans on the walls and floors to keep the air moving everywhere in the room to get even co2 and temperature throughout and avoid microclimates forming in areas with less circulation, it’s also important that things like sensors for ac’s and climate controllers and co2 sensors are giving you a true reading, this is much easier to be sure of when you have good air movement around your room.

So there you have it; a truly perfect room where you are the one dictating what is happening inside your Garden instead of the outdoors doing so. We can help anybody in sizing up any size space. It is relatively easy to calculate the air con, dehumidification and CO2 requirements for a room of any size from a few lights all the way to 50 lights! Any questions or queries regarding Closed Environment Agriculture just come into our shop or give us a ring and we will be more than happy to talk you through anything you want to know on the subject. We love it and do it all day!

Call us now and speak directly to our fully trained staff and we will be glad to guide you through the different configurations.

01483 596484.

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