Growth of Spring Vegetable Plant Seedlings in a Phytochamber with a Low Energy Consumption

Ch. STOIKOV1, I. STANCHEVA2 and I. MITOVA1
1 N. Poushkarov Institute of Soil Science, BG-1080 Sofia, Bulgaria
2 BAS, Acad. M. Popov Institute of Plant Physiology, BG-1113 Sofia, Bulgaria

Abstract

STOIKOV, Ch., I. STANCHEVA and I. MITOVA, 2003. Growth of spring vegetable plant seedlings in a phytochamber with a low energy consumption. Bulg. J. Agric. Sci., 9: 651–657

Lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) were grown subsequently in the phytochamber with low energy consumption in 1 kg plastic pots at two varieties of the soil substrate. supporting of needed temperatures in the working regime is realized on the account of the heat evolved from the illuminative bodies and refrigeration is achieved through the heat transfer with the ambient air. Light was supplied by 6 cool white fluorescent lamps (Philips) L = 36W that ensure irradiance 12 klux at a photosynthetic photon flux density of 144 mmol.m–2.s–1 at the leaf level. The total energy consuption was 153 kWh during the experiment with spinach and 142 kWh during the experiment with lettuce. The conditions created in the phytochamber allow normal germination and growth of spinach and lettuce plants during the early stages of plant development when outside average diurnal temperatures as well as minimal temperatures are unfavourable. The plastid pigment content values are close to those measured in the same plant species grown under glasshouse conditions which show applicability of the chamber for growing early spring vegetable seedlings. The peat reached soil substratum is more appropriate for growing early spring vegetables.

Key words: spinach, lettuce, phytochamber, low energy consumption