I think that substrate temparature during growing season is very important.
Please see the paper given below:
http://hortsci.ashspublications.org/content/30/5/1029.short
What do you think what would be cheap pot insulation techniques (or best pot material itself) in commercial blueberry production in containers.
Or what other alternatives there can be to simulate optimum in-ground conditions (with regard to temparature) in pot growing?
Mine have grown very well where average soil temperature would be upper 70s in summer. So that’s low to mid 20s C. In fact 16C seems too cold to me. You can’t maintain that in most climates in summer without excessive expense.
Piling soil around the edges of the pot would be as good as anything short of burying the pot. You can only do so much by insulating the sides with the top open.
Unless your climate is real hot just shading the pot from direct sun will do the job. Double potting works. Aluminum foil on the outside also works.
Interesting article. Its going to be necessary to lower the temperature of the growing medium for the blueberries in a hot climate in order to achieve good growth and production since the soil in a container should warm faster and reach a higher temperature than soil in the ground.
Pot in a pot production like that used in some large commercial nurseries may help moderate soil temp.
Lighter color pots would moderate soil temperature
Heavy mulch on top of and around the plants would help moderate the soil temp too.
Overhead irrigation would moderate soil temperature
Shade cloth would help moderate the temp, but may impact production and would be expensive
I use overhead irrigation (micro sprinklers) to water about 1000 blueberry plants in containers in my nursery area. It works great since the pots are placed very close together but it may not be practical if the pots were further apart.