Many of you may already know this but I thought I'd share this tip with you as it is new to me.
When planting into teracotta pots (un-glazed ones) make sure you soak the pot in water beforehand. If you don't, you run the risk of the pot absorbing the moisture away from the soil on your first watering making the soil "shrink" away from the sides of the pot. This will create a gap between the pot and the soil and each time you water thereafter the water will drain quickly through the gap and rob the soil and plant of moisture.
