This is a great article on transplanting from about.com gardening
Success Tips for Transplanting and Moving Garden Plants – Water!
When You Water Can Be as Important As How Much
By Marie Iannotti, About.com Guide
Summer is never the best time to move or transplant garden plants. The sun is too intense and the heat is relentless. However, sometimes you have no choice but to move your plants during the hot months. You can successfully transplant garden plants at any time of the year if you follow a few simple guidelines:
- Water the garden plants to be dug and/or transplanted the day before your do it. This insures that the whole plant will be hydrated, leaves and all, when it’s time to transplant.
- Dig and/or transplant when it is overcast or during the cooler evening hours.
- Water the plant immediately before digging or removing from its pot. Soak the root ball so that the soil will adhere to the roots, when it is dug from the garden.
- Never leave the roots exposed to sun, heat or wind. Don’t remove all plants from their pots and place them in the garden. Remove just prior to planting.
- Water the hole before you place the transplant into it.
- Place the transplant into the hole and fill it halfway with water. Allow the water to settle the soil around the roots and then finish filling the hole.
- Lightly firm the soil around the transplant.
- Once again, water the whole plant, leaves and all.
- If possible, shield the new transplant from direct sunlight for 3-5 days. Use a floating row cover or lean a board in front of the transplant to block direct sun.
Check the plant daily for the first couple of weeks. Transplants will need watering every day, if not more. If it is wilting, water the plant. Depending on the weather and the plant, you may need to water twice a day until it becomes established. The larger the plant and/or the less roots to top growth ratio, the more water will be needed.
All of this may seem extreme, but the shock of being uprooted is stressful to plants anytime of year. In the heat of summer, this extra precaution is vital to easing the transition for your transplants.