Propagation of cucurbits in soilless media : A thesis submitted as the requirement for the National Diploma of Horticulture (Nursery Management), New Zealand

Abstract

Considerable numbers of cucumbers and other cucurbit plants are produced by nurserymen and growers , both for indoor and outdoor growing, without a great deal of knowledge on the suitability of media or growing conditions for any purpose. In propagation, plants are being grown for a particular purpose, as economically as possible to suit a particular use by a grower. In order to meet these requirements, the grower must understand the needs of the plant and how these may be fulfilled during propagation in order that the plant may suit its intended use. The standard practice in New Zealand and abroad, during the culture of cucurbit crops such as cucumbers and musk melons, is to raise the plants in containers, in which they are grown on for a period prior to planting out. This p riod, from seed sowing to planting out is referred to as the propagation period. Loam based media of the John Innes formulae (Lawrence, 1934) are probably the mot widely used propagating media for cucurbite in this country, although container production ranges from box grown plant to production in compressed peat discs. Good quality loam for use in John Innes composts is not generally freely available and alternative soilless media are being used without any evaluation of their physical or chemical composition. Although studies have been made on a range of environmental factors during the early growth of cucurbit plants, few suggest any carry over effects to the yield. Studies with other glasshouse crops (lettuce, tomatoes and peppers) show that the plant behaviour later in its life cycle can be markedly influenced by imposing certain environmental regimes during the propagation period, which is of a short period, compared to the whole life cycle of the plant. This thesis will review published literature relating to soilless media as an alternative to loam based composts and experimental work will make comparisons between John Innes type media and soillness media used for cucurbit propagation. It is hoped to establish a correlation between propagation effects and the yield both from glasshouse grown plants and those grown outdoors.