Container Preparation
If your containers have had soil in them, wash with soap and water. Then sterilize them with a bleach solution of 1 part bleach to 9 parts water. Rinse them well and dry before putting your potting soil in them.
If using new terra cotta pots from the nursery, soak overnight in a bucket of water to pre-wet the pot so it does not soak up the moisture from the transplant soil. Before using for planting, wash good with soap and water, rinse well and let air dry for 30 minutes before using for planting.
Do not do this procedure with coir – coconut fiber pots. Throw them away. They are so inexpensive you can afford to replace them.
Some types of containers such as baskets can be used directly by lining with a heavy clear plastic bag with holes punched for drainage and air passage. If you do this, make sure to punch quite a few holes.
Use a drip saucer under individual pots for excess water drainage. These come in both Terra Cotta and inexpensive plastic versions. Make sure to get a saucer large enough for the pot you are using. Line it with some washed river gravel to allow for drainage and air circulation under the bottom of the pot.