Articles
THE CLIMATE WITHIN NON-HEATED SHELTERS
The strong variation recorded during the year tends to hide the relations that must exist between the temperature observed under various shelters and the precocity of a same variety of strawberry plant.
As far as precocity is concerned, the period extending from the setting of the shelter and the beginning of the flowering appears to be determinative whatever the year.
During this period, the strawberry plants – either under shelter or in the open air – need a sum of day-temperature superior to 5°, with an average of 400 degrees-hour if they are to flower.
Since the period between the beginning of the flowering and the mid-harvest does not vary – 40 odd days – the aspect "precocity of the harvest" is already acquired at flowering-time.
An important gradient of earliness appears in the cultures of strawberry plants grown under a huge plastic tunnel.
Its economic importance is sharply marked at a time when prices go rapidly down.
Temperatures should be studied at various places of such shelter and the result should lead to experiments in order to find the best means of improving the temperature.