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

and place slabs on top. The nutrient solution is pumped from the reservoir below the table and delivered to individual plants via spaghetti tubes attached to emitters. The solution flows into the growing medium where it comes into contact with roots. Excess nutrient solution drains from pots onto the table and is carried back to the reservoir. Make sure the table is set up on an incline so it drains evenly. Pockets of standing water on the table contain less oxygen and promote rot.
Individual Blocks
    Individual blocks in this rockwool system allow gardeners the possibility of removing or changing plants if necessary. Nutrient solution is pumped via spaghetti tubes from the reservoir below and distributed via emitters pressed into rockwool cubes.
Vertical Top-Feed Systems
    Vertical gardens can increase overall yield more than ten-fold over a flat garden. Substrate bags, tubes, or slabs are positioned vertically around an HID. Short plants are placed in the medium and fed individually with a drip emitter. The runoff drains through the growing medium and back to the reservoir. The solution is re-circulated once it returns to the reservoir.
    Use rockwool or coco mixed with lightweight vermiculite as a growing medium to lessen weight when substrate is wet. Irrigate constantly to keep roots supplied with water and nutrients from a well-aerated solution.

Top-feed slabs of rockwool fit in individual containers. Spaghetti tubes irrigate plants from the top.

This cutaway drawing shows how nutrient delivery is simple and easy with a top-feed bat system. Aerated nutrient solution is metered via emitter onto a grow cube. Aerated solution percolates down through the medium. Channels in the bottom of the tray speed drainage back to the reservoir.

Nutrient solution from this bat of Canna coco drains into an open trough and is carried back to the reservoir. Salt buildup from the nutrient solution is easy to scrub out of the open trough.

Ebb and flow tables catch nutrient solution runoff and direct it back to the reservoir.

This new vertical garden uses rockwool as a growing medium and compact fluorescent lamps.
    Vertical hydroponic systems save space, but require more maintenance. These systems can also be tricky to fine-tune so they operate at peak capacity.
Nutrient Film Technique (NFT)
    Nutrient Film Technique (NFT) hydroponic systems are high performance gardens that perform well when fine-tuned. This relatively new form of hydroponics supplies aerated nutrient solution to roots located in gullies. Seedlings or cuttings with a strong root system are placed on capillary matting located on the bottom in a covered channel. The capillary matting stabilizes nutrient solution flow and holds roots in place. Constantly aerated nutrient solution flows down the channel, or gully, over and around the roots, and back to the reservoir. Irrigation is most often constant, 24 hours a day. Roots receive plenty of oxygen and are able to absorb a maximum of nutrient solution. Proper gully incline, volume, and flow of nutrient solution are key elements in NFT gardens.
    Gullies or channels are covered to keep humidity high in the root zone and light from shining on roots. Root hairs responsible for most water and nutrient uptake cover the growing tips of advancing roots. These roots are submerged in turbulently flowing nutrient solution and the tops are intermittently in humid air. The nutrient solution is constantly aerated as it flows down the inclined gulley.
    The slope of the gulley is adequate to prevent water from stagnating. Often a filter is necessary to prevent debris from blocking gullies and pump.
    Although high performance, NFT systems offer practically no buffering ability. In the absence of a growing medium, roots must be kept perfectly moist by the nutrient solution at all times. If a pump fails, roots dry and die. If the system dries out for a day or longer, small feeder roots will die and grave consequences will result. The system is very easy to clean and lay out after each crop. Only growers with several years experience should try an NFT system if working alone. With help, they are easier to master.
    Double reinforced bottom makes gullies durable and rigid when supporting large plants, root systems, and large volumes of nutrient solution. Some NFT gullies have ribs below to provide support and prevent warping and movement. The ribs also function as drainage channels and direct nutrient solution evenly along the bottom of the