Inland Northwest Pot size and in ground time.

I live in Eastern Washington State and was wondering if 15gallon fabric pots are a good size for outdoor? And has a date been identified as a good time to put the ladies in the ground? Has anyone had experience with decent supper soil recently? What is the purpose and technique for "cooking" soil prior to placing it in pots? Lastly, is there any less expensive “custom” fabric pot then the 15gallon/$15 type?

Thank you

if you/re going outside, usually around june 10th is a safe bet

15 gallons is small, you'll want at least 100 gallons
you can build it with wood

composting/nutrient breakdown is complex but basically the ph is too low for awhile and the nutrients need to be eaten by the microorganisms first before the plant can use them

Thank you!!