Produktion av lövfällande träd och buskar i täckrotsystem

To grow deciduous trees and shrubs as containerized seedlings is as yet a relatively untried growing method in Sweden and Europe. This paper is a report on the basic conditions of growing containerized seedlings in container system. A containerized seedling is defined as a plant which has some kind of growing media surrounding the roots when it is planted out. The volume of the containers is usually between 50 - 700 cm3 and the plants are grown for one or two growing seasons. Porous peat, or a peat mixture are most frequently used as a growing media. One advantage of having containerized seedlings is that their root systems are kept relatively intact, and that root growth can thus continue undisturbed after planting. The method also has certain technical advantages. On the Swedish market today we find about 10 different container systems. The choice of system must be decided by several factors: the type of plant, the plant nursery, the working environment, the customers demands etc. Growing in container systems makes it possible to use green-houses. During germination and the first growth it is necessary to have some kind of climate regulation in order to obtain a successful growing result. To obtain a good result one has to master the handling of the seeds. Most seeds of deciduous trees and shrubs have some kind of seed dormancy. The causes of dormancy and how to interrupt it is treated here because seed from different species have to be treated in different ways. The sowing method is decided after the germination percentage has been estimated: either sowing directly in containers or replanting seedlings into the containers. For an optimum utilization of the greenhouse area and other resources, it is imperative that empty containers be avoided. There is not much literature to be found about climate regulation and the influence of environmental factors since trees and shrubs are usually grown outdoors. It is difficult to make recommendations when there are differences between species and when the environment must be changed during the growing season. Rearing seedlings can be divided into three parts; germination, growth and cold hardening. During germination it is most important that moisture and a temperature around the seed are regulated in order to obtain a good growing result. Even during growth the greatest benefits are derived from correct regulation of the water supply and of the temperature. The tolerance for nutrients is quite high as long as the dosage is kept within reasonable limits. In the late summer when the plants are outdoors is cold hardening starts naturally when the days shorten and the temperature sinks. Nitrogen fertilization should be cut down gradually during July and August to stop growth. While each species should be studied individually, there is at the end of this paper a short growing recommendation for 10 species, based on literature studies and own research