Sorry I'm so late in responding....
Mary, if you're going to bury the pots in the gardens, is there any reason you don't just plant right in the ground? If you're concerned about providing the optimum planting mix for them, I have found that I can just amend small sections in the ground where I want to plant. That being said, I see no reason why it wouldn't work to bury pots. I would go with the deeper pots rather than the shallow ones though. Keep in mind that terracotta pots will crack if left outside in the winter. The freeze/thaw cycles seem to be really hard on them.
