Seedlings must be irrigated and fertigated with micro sprinklers which are linked to a timer. A simple swimming pool timer will suffice. In arid conditions the seedlings should be irrigated as listed in the table below. Fertilizers should only be applied in the second and third week of growth. Most seedlings should be ready for [...]
Plants must be acclimatized to the shock and stress of transplanting into the greenhouse by slowly removing the optimum growing conditions of the nursery. This is accomplished by a process known as “hardening-off”. To harden off seedlings, commercial growers reduce irrigation frequency lower temperatures and stop applying any fertilizers to the seedlings. Care must be taken to [...]
Most vegetable seedlings are sown in commercial seedlings trays. These trays are made of either polystyrene or hard plastic. The numbers of plugs per tray vary from 50 to 300 depending on plant characteristic. The most common tray used is the 200 plug tray made from polystyrene. The trays are 30 cm wide, 70 cm [...]
Seedling growth medium fall into two categories. Those used for commercial seedling trays and mixtures used for propagating seedlings directly in the soil. Commercial seedling growth medium mixtures are relatively expensive if small amounts of seedlings are to be produced. They are also most suited for seed trays. These mixtures are of the types A, [...]
Seedlings must be protected from extreme temperatures. Climates that vary from very cold to very hot and also from very dry to waterlogged conditions are detrimental to seedling production. The table below provides a quick summary of the effect of extreme temperature conditions on seedling production. Any stress a seedling undergoes will have a cumulative [...]
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 [...]
It is a proven fact that the production of seedlings in seed trays will on average provide a better quality seedling which will permit earlier harvesting and higher yields. Most growers buy their seedlings from a reputable seedling grower who specializes in the production of seedlings. They have facilities that are dedicated to seedling production [...]
Proportioner systems Open hydroponic systems lend themselves to two different automation systems i.e. proportioner and injector systems. First let look at what a proportioner does. A proportioner can either be electrical or mechanical device that adds liquid, coming from a tank or other source, into a main line in specific ratio’s. For instance, the ratio [...]
The word ‘chelate’ is derived from the Greek word meaning ‘claw’. Many of the micro elements such as Fe, Mn, Cu and Zn are difficult for the plant to absorb and in some cases, deficiency symptoms may occur if these micro-elements are not made available to the plant in chelated form. A chelate is a [...]
