MEDIA EVALUATED FOR EXTENDED SWEET-POTATO TRANSPLANT PRODUCTION IN HEATED BEDS

Georgia Jet' sweetpotato [Ipomoea batatas (L.) Lam] transplants were p roduced in heated beds to compare aged pine sawdust or builders' sand (traditional media) to fresh pine bark and aged pine bark, or fresh pi ne sawdust (alternative media), with regard to transplant production a nd quality over an extended harvest period. At the first harvest, high est transplant numbers (mean 1400 transplants/m2) were obtained with f resh pine sawdust or fresh pine bark. Media effects on transplant numb ers at the first harvest agree with the results of an earlier experime nt. The greater productivity of fresh pine bark compared to aged pine media and builders' sand at the early-harvest (two harvests) in the pr evious experiment was not confirmed in this experiment. Extended-harve st (four harvests) transplant production was greater with fresh pine s awdust (2030 transplants/m2) than with aged pine sawdust (1380 transpl ants/m2), but was not greater than the number of transplants produced with the other media. Transplant production averaged over the five med ia, decreased from 1060 and 360 transplants/m2 at the first and second harvests, respectively, to 130 transplants/m2 at each of the last two harvests. Differences in mean transplant weights due to media were fo und only at the third harvest. At the first harvest, greater mean leng ths of transplants gown with the fresh pine media (mean 25.7 cm) than with the aged pine media (mean 21.4 cm). Shortest transplants were pro duced with builders' sand at the first harvest (17.8 cm) and throughou t the extended season (17.5 cm). Similar effects of media on mean tran splant length were observed at the early- and extended-harvest periods . Media had no effect on the percentage of intact roots at the end of the 15-week season (mean 71%).