抄録
A simple water-culture for leafy vegetable using controlled-release fertilizer and rockwool was tested in this study. The recommended application is N. 0.5g pot-1 (plant-1) with 70 day and 100 day types. The concentration of nitrate, phosphorus and potassium from the controlled-release fertilizers was sufficient for plant growth and each varied within the range of the standard culture solution (Enshi-shoho) . The fertilizers would be able to be used for water-culture methods which store nutrient solutions and they would be adequate for the double-cropping of leafy vegetables such as lettuce growing for about 40 days. However, it seems that the concentration of ammonium from the fertilizers was excessive and the concentrations of Ca and Mg would be insufficient for plant growth, though they never induced excess or deficiency symptoms.
