Protect your plant by preparing the herb garden before you plant the basil. A week before transplanting, turn the soil well and mix in plenty of nutritious compost. On the day of planting, sprinkle a moisture-retaining polymer soil additive into the planting hole before inserting the plant roots and covering the plant base with topsoil. The polymer reduces the amount of water you need to keep your herbs from burning in the sun. Pack compost and mulch around the plant to keep the roots moist, allowing the plant to continue to thrive in the heat.
Think ahead to the hot summer months when you lay out your garden to protect your plants from burning. Snake a flat soaker hose through the area around your newly planted basil plants. Cover the hose and the dirt around each plant with shredded newspaper, and water the entire area until the newspaper is soaked. Keep water trickling through the hose when daytime temperatures remain in the mid-90s or higher. The newspaper reduces the evaporation rate and deters weeds in addition to keeping the plants from burning in the sun.
One way to keep your basil from burning under the sun is to plant it in a movable container. Set your plants out in a box or pot with at least 6 inches of soil and compost mix. When temperatures spike, put the container in an area that receives shade for part of the day. Remember to water the container every other day because potted plant roots have no access to groundwater. Once the daytime temperatures drop below 95 degrees, move the container back into full sun.
Keep your basil plants in pots that can be moved into the house when the summer temperatures and sun bake your plants. Place the plants in a window where they continue to get plenty of sun but suffer less from the drying heat. When returning the plants to the outdoors, make the move gradual by placing them in partial shade where they will stay cooler. Change their location once each week, placing them closer to full sun with each move. Keep the soil moist with daily watering to reduce the shock from warmer and dryer conditions.