The Effect of Cell Size On Organic Transplants for Field Establishment

Trends towards sustainability have motivated a new interest in producing healthy transplants. Transplant production of bedding plants, vegetables, pot crops, cutflowers, tissue culture materials, trees and seedlings have become a worldwide business. Transplants are fast replacing traditional bare-rooted transplants or direct seeding in horticulture industry. However, the significance of transplanting stage based on root mass and shoot size is documented only in relatively few crops, and this information is even more limited for organic transplants. The objective of this study was to establish early stand in the field to take advantage of early demand and premium price. Therefore, an experiment was conducted to investigate the optimal transplant (plug) size for transplanting in the field immediately after the last frost in the spring. Amaranth (Amaranthus spp.) and Bok Choy (Brassica chinensis) organic vegetable seeds were sown in plug tray cells of 288 (6.4 c.c), 242 (10 c.c), 162 (20 c.c), 128 (28 c.c), 98 (35 c.c), and 72 (56 c.c) containing coir substrate. These transplants were transplanted in the field beds at the same time. The transplants grown in larger cell size were significantly larger with higher root mass and density than the transplants of same age grown in smaller cell size. The larger transplants established easily and quickly, and were ready for early harvest than the smaller transplants. However, the transplants grown in larger cell size needed more greenhouse space, substrate and fertilizers.