I think it depends more on where the ground and pots are located, and the soil in those places - plants near the house get more radiant warmth, and pots tend to dry out more, so if your soil gets waterlogged that's bad. I had exactly the opposite experience in SoCal because the pots soil dried out faster than I could water them. Also, pot soil is usually made for plants, but ground soil usually needs some love and attention. :]