Abstract
A lengthy (4-yr) nursing period is necessary for raising containerized seedlings of the spruce tree Picea jezoensis Carr, and here we sought to devise a method to shorten this long nursing period. We examined 84 treatments and identified the optimum conditions for shortening the nursing period: four environmental conditions, three types of multi-cavity containers, and seven types of growing media. When we raised containerized seedlings using 300-cc multi-cavity containers with 100% coco-peat as the growing medium in a glass greenhouse in which high-pressure sodium lamps were equipped to create 18-h-long-days, the height and root color dia. of 77% of the containerized seedlings were > 20 cm and > 4 mm respectively, which is a tentative 2 nd standard size of containerized Picea glehnii seedlings, and these results were achieved within 2 yrs. We also observed that the promoting growth effects on the seedlings were similar among provenances in the glass greenhouse equipped as described above. This technique thus has the potential to significantly shorten the nursery period of containerized Picea jezoensis seedlings.
