Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

gully.
    Many NFT systems are hybrids. For example, the nutrient solution in some hybrid NFT systems is delivered via spaghetti tubing to each plant. More irrigation sites help each plant receive proper irrigation. The nutrient solution flows through a small basket of growing medium before it runs down the gulley, over the roots, and back to the reservoir. Yet another hybrid NFT system employs spray nozzles inside the gulley. The nozzles spray nutrient solution on and around roots to keep the root zone environment at 100 percent humidity. The nutrient solution flows down a PVC pipe, over roots, and back to the reservoir.
    Too often, these hybrid systems are poorly planned and designed. Many times they are constructed from white four-inch PVC pipe. The thin white walls of the PVC pipe allow enough light to illuminate roots that they turn green or rot more easily. I have also seen systems with nozzles inside the PVC pipe. If a nozzle plugged inside the pipe, there was no easy way to access the nozzle for maintenance.
    Nutrient solution is pumped from the reservoir into gullys via a manifold and tubing at the upper end. The table is set up on an incline so the nutrientsolution flows quickly over roots to create an environment packed with air and available nutrients. A catchment drain directs the nutrient back into the nutrient reservoir.
Aeroponics
    Aeroponic systems use no growing medium and offer the highest performance possible. Roots are suspended in a dark growth chamber without growing medium where they are misted with oxygen-rich nutrient solution at regular intervals. The humidity in the chamber remains at or near 100 percent 24 hours a day. Roots have the maximum potential to absorb nutrient in the presence of air. Humid air and nutrient solution are all that fill the growth chamber. Plants are most often grown in net pots full of growing medium and suspended from the top of the system.

Gullies with rounded corners are very popular in Australia. Growers who use them say the nutrient solution flows more smoothly.

Many gullies are flat on the bottom. Capillary matting is placed on the bottom under the growing cubes. The capillary matting anchors roots and helps direct nutrient solution evenly over roots.

Small net pots are preferred for most NFT systems. Larger net pots are used in NFT systems as well as top-feed hydroponic systems.

Nutrient solution in this hybrid NFT system is delivered via nozzles attached to a PVC pipe inside the main growing tubes.

Stagnant nutrient solution and salt buildup stifle root development. Soon roots turn dark and rot Note burned and discolored leaves that signify salt buildup.

    Roots in this NFT system are strong and healthy. This system produced a heavy harvest of buds on robust plants.

Long root systems develop quickly on cuttings in this Rain Forest aeroponic system.

Rooted clones and seedlings grown in aeroponic systems develop exceptionally fast. To grow clones, simply insert clone stems into the growth chamber and turn it on. The roots will grow in a perfect environment to develop roots.
    Aeroponic systems require greater attention to detail. There is no growing medium to act as a water/nutrient bank, which makes the system delicate and touchy to use. If the pump fails, roots soon dry, and plants suffer. Systems that use delicate spray nozzles must be kept free of debris. Imbalanced nutrient solution and pH can also cause problems quickly. This is why it is important to purchase quality components or a ready-made system from a qualified supplier.
    The Rain Forest ( www.generalhydroponics.com ) is very popular. Nutrient solution is actually atomized into the air creating 100 percent humidity. Nutrient solution is dripped onto a spinning plate. The solution atomizes, mixing with the air as it spins off the plate. The spinning plate is located above the water in the reservoir.
Growing Mediums
    Soilless growing mediums provide support for the root system, as well as hold and make available oxygen, water, and nutrients. Three factors contribute to cannabis roots’ ability to grow in a substrate: texture, pH, and nutrient content, which is measured in EC, electrical conductivity.
    The texture of any substrate is governed by the size and physical structure of the particles that constitute it. Proper texture promotes strong root penetration, oxygen retention, nutrient uptake, and drainage. Growing mediums that consist of large particles permit good aeration and drainage.