Use of controlled-release fertilizer in limited amount of soil and sand medium for netted melon cultivation using a root-proof capillary wick was investigated. The first experiment consisted of 3 lots of soil medium. 1) 3L medium used throughout the cultivation period (A); 2) 6L medium used throughout the cultivation period (B); 3) 3L used until pollination stage, then a partitioning board removed to increase the growth medium to 6L (C). Average of one fruit weight was 1.4 kg in A and B, but only 1.2 kg in C. Brix° value was 13.1 in A, 13.6 in B and 13.4 in C, respectively. The stem diameter at the time of pollination was largest in B in which there was fruit cracking that was also observed in C, but not in A. The root dry weight was highest in A. These results indicate that the restricted medium of 3L presents a potential for good fruit production. The second experiment consisted of 4 lots with 3L medium each: 1) soil and fertilizer medium as in experiment 1; 2) sand and fertilizer medium as in lot 1); 3) sand and slower release fertilizer; 4) sand and half of fertilizer at planting and an additional fertilizer bag placed on the wick at time of pollination. Although cracking fruits occurred 75% in 3) and 37.5% in 4), there was no cracking of fruits in 1) and 2), in which fruit weight in the latter was 1.5kg and brix° value of 14.5 was obtained. These results indicate that controlled-release fertilizer is useful for fruit production
of netted melon in sand medium of 3L with a high potential for reuse.