GROWTH OF PLANTS

Waikato Times, Volume 127, Issue 21176, 27 July 1940, Page 19 (Supplement)

GROWTH OF PLANTS

TIME OF QUICKEST GROWTH Some work has already been done by plant physiologists to determine which particular rays of the sun’s shaft are promoters of strongest growth. A further matter for investigation lies in ascertaining the special hours of the day or night that conduce to quickest growth. There is an instrument devised to record the rate at which plants grow, but this is more for laboratory purposes. How plants respond in growth to the varying intensity of the sun’s light from the time its first beams shoot low across the eastern sky until they fade away beneath the western horizon is an open-air study. General observation would indicate that plants make most growth by night, at least there is more sign of stretch and expansion on mornings. Recently a writer on cricket grounds and lawns asserts that weeds seem to flourish in greater abundance on parts of a ground where the early morning sun first strikes. Another writer, commenting on this observation, claims it to be in accord with the teaching of the scientists that the greatest growth of plants is during the first hour or two after sunrise; consequently the further statement is made that plants in a garden which face the morning sun are feund to be generally stronger and better developed than those in other parts of the garden. It is unquestionable that plants susceptible to night frosts, such as potatoes, are liable to be burnt il exposed to the early sun to a greater degree than those shaded for some

time till the day temperature has risen somewhat. Whether it is true or not, it will be generally admitted that plants appear to make most growth between nightfall and the morning hours of the next day. That this growth, however, has mainly taken place during the first hours of exposure to the early sun’s rays would require to be more accurately proved than by a more general in&peulion after the night's interval.