Effects of Medium Shape, Fertilization Methods and Plant Density on the Growth of Pansy Grown in Medium Hardened by Heat Fusion Polyester Fiber without Polyethylene Pot

To develop bedding plant production system without polyethylene pots (PP), problems that may be encountered with compacted medium hardened by heat fusion polyester fiber were investigated. Effects of medium shape, fertilization methods and plant density on the growth of pansy in medium without PP were investigated. To improve water usage on compacted medium, a watering space (6×6×depth 3cm) was made on the upper part of the compacted medium (9×9×depth 9cm). In the early stages of the experiment the amount of water supplied per pot (weight after irrigation-weight before irrigation) of medium with water space was 10–25% greater than that of medium without a water space. However, from the mid to late stages of the experiment, the difference gradually declined. The amount of water supplied per pot was similar between with and without water space especially on cloudy or rainy days. The growth of pansies on medium without PP was remarkably greater with water space than without water space. On 10g/liter basal fertilizer treatment, pansies had severe symptoms of fertilizer damage. The growth of pansy on 10g/liter basal fertilizer was inhibited compared to that of 5g/liter basal fertilizer. Spacing treatment was conducted whenever plant density was half. Height of pansy grown with spacing treatment was significantly lower than that without spacing treatment. PP had no effects on growth when pansy was grown without spacing treatment. However, when pansy was grown with spacing treatment, pansy grown without PP had significantly greater growth than with PP. Algal growth on the medium increased with increasing irrigation rate or nutrient rate. Combination of spacing treatment and medium without PP decreased the rate of algal growth on medium.