Various methods exist for making a homemade hydroponic system. These range from the very simple hand-watered reservoir systems to the more complex waterworks grids or vertical walls constructed out of polyvinyl chloride (PVC) tubing. Among these varieties, the principles of hydroponics remain essentially the same: water-loving plants are suspended in an inert substrate like gravel, perlite, mineral wool, vermiculite, or coconut husk, with roots immersed in grow trays or fed with wicks in a mineral-nutrient, aerated solution. The process can generate higher yields of nutrient-specific produce; it eliminates soil, reduces irrigation, attracts fewer pests, and can produce indoors or outdoors year-round.
The first step in creating a homemade hydroponic system is to choose which method you prefer, and how easy or complex you wish to make it. You could choose to put planters on packing foam floats in a fish tank reservoir, or create an individual bucket or buckets, each equipped with a water pump and an aquarium heater. You might even construct a water-fed shelving system of PVC tubes cut with holes to support individual planters or cups. The general idea is to suspend your planter in a supporting vessel and allow water to infiltrate your planter through holes that still keep in your planting medium. You can run the water by hand or automatic pump, making sure to infuse the planter substrate with oxygen bubbles, and to maintain water flow against evaporation or stagnation.
After researching the various techniques available and choosing the most appropriate one for your space and energy requirements, it's time to get building. Consider, for example, a hydroponic gardening method that combines the nutrient film technique and deep water technique. The nutrient film technique (NFT) continuously feeds water through the system in order to generate plenty of oxygen for the plants. The deep water culture (DWC) technique keeps water level high to immerse roots continuously in the system. This homemade hydroponic system can be constructed using two 10-foot (about 3 m) PVC tubes connected by two elbow joints and capped on the open ends.
Using a hole saw, drill holes of about 4 inches (about 10 cm) to 6 inches (about 15 cm) along the top of the tubes every foot (about 30 cm). At the end of the system, insert a small aquarium pump of about 60 gallons per hour (GPH), or 227 liters per hour (LPH); run its hose out and across to the other PVC tube. The water should circulate throughout the system and ensure a uniform spread of oxygen for the plants. Add a couple of airstones to help in aeration. An aquarium heater helps to regulate temperature.
Add planters, or drill holes around the bottom thirds of large plastic cups, and fill the tube with nutrient-water mixture. Add plant and substrate to the cups, and immerse until the bottom of each cup is under water. Make sure to monitor your homemade hydroponic system for leaks or other changes. Add to the basic design outlined here to create other rows and tubing configurations. Grow lights add even more control over growth conditions.
Plants that do well in hydroponic grow rooms include typical salad varieties: lettuce, tomato, spring onions, radishes, and green vegetables. Herbs are also popular. The size of the plant will depend upon the space allowed for their roots; this makes larger plants less suitable for hydroponic gardening. Remember to arrange and space your homemade hydroponic system to allow plants to receive enough light, and you'll soon be harvesting without digging a weed.