SOME EFFECTS OF CO2, AIR TEMPERATURE AND SUPPLEMENTARY ARTIFICIAL LIGHT ON THE GROWTH OF YOUNG TOMATO PLANTS

A.E. Canham
During the last three winter seasons, experiments have been carried out with young tomato plants grown at two levels of atmospheric CO2 (normal and 1000 v.p.m.), two air temperature régimes (national "blue print" temperature and 2.2°C above "blueprint") and two levels of light (natural daylight and daylight supplemented with artificial light), in factorial combination. Supplementary light was the most effective single factor for improving the rate of plant growth, the time to first flower and the early crop.

Significant interactions between air temperature and CO2 level were obtained which were not consistent from one season to another, and in the second year there was a second-order interaction between all three factors. Generally, however, the effects of higher CO2 levels were not large enough to be statiscally significant and the effects of increased temperature levels were even smaller.

The results confirm earlier recommendations that supplementary light is an effective way of reducing the propagating time of young tomato seedlings, and is more effective than CO2 enrichment.

Although in most cases the effects of CO2 and artificial light were cumulative, the evidence is not strong enough to recommend the use of CO2 as well as supplementary light in commercial practice. The use of higher temperature levels likewise cannot be recommended.

Canham, A.E. (1974). SOME EFFECTS OF CO2, AIR TEMPERATURE AND SUPPLEMENTARY ARTIFICIAL LIGHT ON THE GROWTH OF YOUNG TOMATO PLANTS. Acta Hortic. 39, 175-182
DOI: 10.17660/ActaHortic.1974.39.17
https://doi.org/10.17660/ActaHortic.1974.39.17

Acta Horticulturae