soil temperature variation with depth in a bulb garden
Alberto Castillo (Wed, 20 Nov 2013 11:51:04 PST)

The Dutch bulb industry is based on experiments like Gastil's. Of course the info will not be made public as it implies commercial success. It is the reason why they can grow in cold barren Holland hundreds and hundreds of different bulb types unfailingly.

Gastil, you can cool your summer soil temperatures by putting a shadecloth cover and it will do wonders.