Marijuana Cultivation/Fundamentals/Dirt vs Hydroponic
Dirt vs Hydroponic
This selection is very fundamental to how you will grow from here on in. That said, it is possible for a skilled grower to achieve similar results using either method. The myths surrounding this choice are many. There are those who claim that hydroponic (or hydro) bud has a bad, chemically, metallic taste or that soil grown marijuana isn't potent. Although there is plenty of bad tasting hydro and weak soil grown marijuana these differences are caused by poor practices elsewhere in the growing process and not whether soil or hydro is used as the growing method. For instance, hydro growers are often commercial growers who are trying to output as much marijuana in as short a time as possible. These growers do not take the time to purge and cure their plants at the end of the flowering cycle and after harvest. This is rumored to cause the bad taste. It is entirely possible to make this same error with a soil grow.
Dirt carries a number of benefits and pitfalls. Dirt is easy to acquire and easy to maintain it is literally all over the ground. Dirt allows you to mix your nutrients into the potting soil rather than having to carefully mix up nutrient solution with each watering. Dirt retains moisture for a period of days so if you go on vacation no special steps will be needed. Dirt buffers the roots of a plant from nutrients and PH fluctuations. This is both good and bad. When you add nutrients they are delivered slowly and it may take longer before the effects of doing this become apparent. It is very easy to over water in a soil grow. This is a common beginner mistake. You should always allow the soil to dry completely to the touch before watering again. This is needed to allow oxygen to get to the roots.
The ideal PH for soil grows is 6.5 and can be taken by measuring the runoff when you water. The best way to maintain the PH on a soil grow is to maintain the PH of the water you are using. This range allows the uptake of manganese. The utility of this nutrient in plant growth is debated but what is not debated is that manganese is not available to the plant at the ideal hydro PH.
If a PH or nutrient imbalance occurs in a soil grow it may be corrected by flushing with lots of water or using a flushing agent such as clearex. In a pot it should be at least three times the capacity of the pot. Outdoors in the ground you should flush with water thoroughly with a hose or bucket.
Hydroponic systems range from very simple to very complex. Essentially the only thing that differentiates a hydro system from a dirt grow is that in a hydroponic system a solution of nutrients and water delivers all nutrients to the plant and the physical medium that the plant grows in is inert with no nutrient content. The advantage of hydroponic methods is that they provide more rapid nutrient availability to the plant. This allows the plant to drink as much nutrient as it likes and produces larger plants in a shorter period of time and smaller space. Popular methods include:
Ebb and Flow
An ebb and flow system uses a timer to activate a pump that periodically floods the plants grow medium with nutrient solution and then drains the solution out.
Often these system are designed using two plastic tubs, one sitting in another. The bottom tub contains the nutrient solution reservoir, the water pump, and an air stone (more oxygen means healthier roots) and the top tub or tray contains the plants. A single hole in the top tub allows the pump tubing into the tub, when the pump shuts off or in the event of a pump failure the water drains right back down the hole it came out of. It is usually best to put another hole where it will drain down to the bottom tub at the highest level you want the water to reach. This prevents flooding. A system like this can run at different intervals depending on the grow medium you use but a common choice is 15min on and off cycles, or 30 minute on and off cycles.
Be very careful with a system like this. If a pump failure is not detected plants can die in a very short time period.
PH and Nutrient problems can be corrected in the reservoir without the need to fiddle with the plants themselves.
Deep Water Culture
Deep water culture is a very popular technique where one bucket is fitted into another. In the bottom bucket is placed an airstone (limewood or porous stone) and in the top bucket holes will be drilled to allow nutrient solution to flood the bucket to a certain level. The airstone provides oxygen to prevent the roots from rotting even though they are submerged. This is a very simple system to build but requires a pot for each plant.
Correcting PH and nutrient problems is a matter of changing the solution and rinsing the plant medium with clean water.
Nutrient Film Technique (NFT)
Nutrient film technique involves plants potted so their roots dangle down into a thin film of constantly running nutrient solution. This technique can work well for large scale hydroponic growing operations but if the nutrient film is interrupted it can be devastating. A separate reservoir is maintained in this technique and it is not commonly used in practice.
Aeroponics is a relatively new technique. A fine mist of highly oxygenated nutrient solution is sprayed onto the roots of the plant which are suspended in air rather than bound in soil or another medium. One benefit is that the roots do not have to establish a taproot that pushes through the soil, this allows it to use it's energy to grow rather than push. The nutrients that are sprayed into the air are also recollected and reused into the system that is enclosed. This helps reduce the amount of evaporation. This is also important in regards to the fact that you do not want light hitting your roots, it can send the plants into shock. Light can also be a problem by allowing mold or bacteria to propagate. Choose containers that are light proof.
Wick systems and Hempy buckets are very similar. In a wick system a pot with medium has a wick placed down it that extends down into a reservoir and draws up nutrients via capillary action as they are needed or water evaporates. This is much like the way a lantern or wick lighter works, drawing flammable fluid up the wick to be burned until it is exhausted.
The hempy bucket is named after the forum poster who claims to have developed it although the concept may date back further. A simple 2.5 to 5 gallon bucket has a 3/4 inch hole drilled about 2-2.5 inches above the bottom. Depending on the medium and size of the medium used it may not be needed but it is common to glue a piece of plastic screening over the hole on the inside of the bucket. This bucket is then filled with a mixture of perlite and vermiculite (popular mixes are 3 parts perlite to 1 part vermiculite and 1 part vermiculite to 1 part perlite).
The bucket is then watered with full strength nutrient solution every 3-4 days, you water until nutrient comes out the hole in the bottom. This flushes out any built up nutrient salts with every watering assuring that you have a perfect balance.
A hempy is as simple as hydroponics gets and is capable of producing the same yields and quality output as other more complex hydroponic systems. Because it allowed to mostly dry between waterings and pulls nutrients up via perlite wicking the roots are very well oxygenated. Since fresh nutrient is added every 3-4 days there is no reservoir to become imbalanced. Although it looks like dirt the perlite/vermiculite medium is completely inert, it contains no nutrients and provides no PH or nutrient buffer. Plants can drink all the nutrient they want just as in other hydroponic systems.
The hempy system has the advantage that because it is simple there are fewer mistakes to be made. Also important is the fact that the hempy bucket has no pumps of any kind that can fail without you noticing. Hempy buckets can be used in a greenhouse outdoors with no power at all. Like a soil grow the medium retains moisture so you can leave the bucket for up to a week with no adverse affects.
The downfalls compared with other hydroponic systems are that plants must be moved one by one in buckets if moved. You also must water a hempy bucket by hand every 3-4 days and with a large number of plants that can become very labor intensive. For instance, for someone who could not carry a five gallon bucket filled with water a hempy installation of more than 3-4 plants would probably be unmanageable unless the water source was very close by. Because you flush out the nutrient solution and any unused nutrients in it every few days the hemp bucket also requires more nutrients than other hydroponic methods.
Continuous Drip System
Another popular technique is the continuous drip system. With a continuous drip a reservoir (often large outdoor garbage cans or 5 gallon buckets) are used with a pump to push nutrients and water through a hose. Some guerrilla growers don't use a pump because they don't have the pressure of a hose to actuate it. The hose will have holes or drip emitters placed at the base of each plant as to get the water right where its needed (the roots).
Consideration and Pitfalls
It is important with any hydroponic system to remember that there is no buffer. Plants will respond very quickly if there are no nutrients and/or water or the pH of the nutrient solution is incorrect. Roots need high oxygen levels or they will rot. And of course remember that plants need space to grow and should never be planted where their roots will intermingle.
Ideal pH level with hydroponic systems is between 5.8 and 6.3 depending on the nutrients that are used, however a consistent pH of 6.0 is very common. The best way to handle a pH adjustment depends on whether you are using a reservoir or not. In a hempy bucket the best solution is to flood with nutrient that is corrected. This will push out the imbalanced nutrient. With a reservoir pH can be adjusted in the same manner as the water with a pH up and pH down solution.