These steps apply to vegetables you get in packs at the garden center, as well as annual and perennial flowers.
1. Dig a hole. Make the planting hole as deep as the plant's container and about double the diameter.
2. Water the plant. Give it a drink before planting, because until the roots start growing, they can't draw water from the soil.
3. Remove the plant from the pot. Place your hand on top of the pot, with your fingers around the plant's stem. Turn the pot upside down and gently squeeze it or push the plant out from the bottom with your other hand. If you must tug it out, pull it by its leaves rather than the stem (if a leaf comes off, no harm done; damage the stem, and the plant will not survive).
4. Check the roots. If the roots have wrapped around and around the plant, gently pull a few loose with your fingers.
5. Place it in the hole. Set the plant in the hole at the same depth it was in its pot, generally where the stem meets the roots. Tomatoes are an exception to this rule—plant them deeper.
6. Replace soil and then water. Backfill the hole with the soil you removed and press gently to ensure that the roots have solid contact with the soil. Be sure the soil stays consistently moist until you see the plant start to grow.
Key to success: Transplant on an overcast day to give the plants a chance to adjust to their new home without being withered by direct sun.