A simple layout of a nursery using raised seedbeds on which the common 200 plug seed tray will fit can be seen below. Each of these seed trays, made from polystyrene, is approximately 700 mm by 300 mm. The width of the stands should be at least 1400 mm if the seed trays are to be placed in their length across the stands. It has been found that by placing the trays in their length across the stands, the space inside the nursery is used optimally. Nutrients are added into the system via a venturi valve which can be activated through a solenoid valve linked to a timer. Depending on the size of the nursery, each set of seedling stands may have a solenoid valve which can be activated separately depending on the growth stage of the seedlings. However with small nurseries this amount of control is not necessary. The irrigation pipes need not be thicker than the common 20 mm PVC pipe. Use 360° sprinklers at 1.0-1.5 m intervals. Never use the type that sprays a fine mist. Rather use those types that spray a small droplet. During windy conditions the mist will never reach the trays while the chance is greater that a small droplet will fall on the tray. It does not matter is the sprinklers spray onto the ground of sprays over the seedling trays, rather over spray than cause many dead spots where seedlings die due to a lack of water.
I studied agriculture at the University of Stellenbosch in South Africa in 1984 and completing my M.Sc Agric. in 1998. . My love for "Controlled Environmental Agriculture" (CEA), started in my third year when I was exposed to the Welgevallen Research Station. There Prof. P.C.Maree showed us what hydroponics consisted of. It was awesome. There were no large tractors involved, no dusty fields, no uncontrollable storms to destroy your crop (well that is what I thought). Since then I put hydroponics to much better use, not just farming. We solved pollution problems by cleaning mines effluent with hydroponics and aquaculture. They were used to remove toxic metals to produce clean water (which we sold and make more money of than the produce). What I learned from 1987 I tried to compile in this website and I hope it is from some value to the serious commercial farmer that wants to take the journey into Commercial Hydroponic Farming.
Seedling susceptibility to various climate conditions is important to growers, especially those wanting to venture