Hydroponics is a process of growing food crops without soil using a nutrient solution. Within a greenhouse, hydroponically growing food crops is fast, productive and better for the environment than growing outdoors using chemical stimulants, weed and pest controls. The initial cost to setup a hydroponic system large enough to grow food crops in a greenhouse may be high, but most of the system components can be reused for many crops and several growing seasons.
Good food crops for hydroponic growing include: tomatoes, peppers, lettuces, herbs and spinach. Growing special varieties of your favorite plants when they cannot be grown outdoors is a significant advantage of hydroponic growing in a greenhouse.
Assemble your ebb and flow hydroponic system and plant stand making sure that the plant stand is sufficiently strong to hold the plant trays when they are filled with nutrient solution. Place the system inside your greenhouse.
Place the water pump into the reservoir and connect the tube between the plant tray and the reservoir. If you are re-using your hydroponic system, be sure that the drain is clear and the tubes clean.
Connect the timer to the water pump.
Follow instructions on the nutrient solution container to correctly dilute it for the food crops you are growing and the plant's stage of development---seeds, seedling, leaf production, blooming and producing fruit. Add to reservoir.
Add plants into the growing tray and fill the tray with growing medium usually pebbles, rock wool or vermiculite. Larger food crop plants like tomatoes and peppers should be placed in their own containers. Leaf crops may be placed in the growing medium or into pots. Remember that the pots or growing medium must let the plant roots contact the nutrient solution.
Set up a vertical crop support system using netting or trellises for tall growing food crops like tomatoes and cucumbers. Most commercial netting and trellising systems come with a stand or you can attach the ends to lateral beams in the greenhouse.
Set the pump timer for several cycles per day. Some food crops need to have nutrient cycles every 30 minutes, others can be done once per hour. If you are not sure, check the plants roots. If they are drying out, increase the number of cycles. On the other hand, if there is still solution in the plant tray, decrease the number of cycles.
Monitor greenhouse temperatures and open vents when the temperature exceeds 90 degrees Fahrenheit.
Add additional light from grow lights if your greenhouse plants will be getting less than 12 hours of diffuse light per day.