PEAT IN CONVALLARIA GROWING

Growing of Convallaria pips for forcing has a centennial tradition in Germany. Consequently there is plenty of empirical knowledge for today's use. It can be said, however, that scientific research is rather scarce in view of the long tradition and quantity of lily-of-the-valley growing. RICHTER (1957), BUNGER (1961), STEFFEN (1961) a.o. have shown, that root stocks grown in sandy loams rich in humus develop stronger than those from soils with less humus. After ZWEEDE (1930) presented the phases of development of Convallaria, it was learned that in certain limits it is possible to regulate the development of different growth phases with growing and storage technique (HARTSEMA and LUYTEN 1933, RICHTER 1957, MAATSCH and HERKLOTZ 1962). The knowledge and control of pests and diseases of Convallaria is deepened (RICKERT 1961, FRANZ 1963). In Finland LANNENP'A'A (1930) and REIJONEN (1962) a.o. have published their own experiences of lily-of-the-valley propagation. Today the great amount of handwork, some phases of growing require, and nematodes are the main problems of the propagation of lily-of-the-valley and growing of pips for forcing. Developing of growing technique and control methods of nematodes has therefore been one of the objects of research at the Department of Horticulture, where Convallaria propagation has been one of the research projects since 1965.

Encouraged by the results professor, Ph.D. PUUSTJARVI (1962, 1962a, 1965, 1965a, 1965b, 1966) obtained in his research work with peat as a growing substratum for greenhouse and field crops, peat was included in our experiments, preliminary results of which is given here.

The influence of growing medium in propagation of Convallaria, and production of pips for forcing was followed in a series of experiments, where there were four growing substrata: 1) sandy loam in good growing condition, 2) the same mulched with fertilized peat*; peat mulch was five cm thick, and it was spread on plots after planting, 3) fertilized peat, 4) peat basin, i.e. 20 cm thick layer of fertilized peat in a plastic film basin. The grade of decomposition of peat was peat mould. Race of