What is Full Sun?
Most lettuce packets will say ‘grows best in full sun.’ It’s important to define what full sun means in gardening. Any place in the garden that receives 6 hours of direct or dappled sunlight a day is considered full sun. Often gardeners will have areas that get full sun in the morning, and others that get full sun in the afternoon. Since lettuce enjoys cool sunlight, it tends to do best in morning full sun.
During high summer in the northern hemisphere, the sunlight reaching the earth is direct and intense, creating the warm season. During spring and autumn months, the light is spread over a larger area, and it isn’t as concentrated. Lettuce grows best in this spring and autumn due to less intense sunlight and cooler temperatures.
Shade to Prevent Bolt
There are several ways to provide lettuce plants with shade during the rights times of the day or season. Often the most robust plants come from areas of the garden that are protected from intense midday sun and heat. They include:
- Dappled Light
- Companion Plants
- Shade Cloth
- Sunscreen Fencing
Choose a location beneath a tree or canopy that receives only dappled sunlight during the hottest parts of the day.
Plant lettuce amidst taller companions like broccoli, tomatoes, or asparagus. These companions will allow light in while the plants are small and the weather is cool. Then as it warms they will grow tall providing shade for sensitive lettuce plants.
Shade Cloth is easiest to accomplish if lettuce is planting in rows. Easy row covers can be made with PVC and garden shade cloth. Raised beds are also easy to outfit with shade covers. If an overhead cover isn’t an option, consider running a small fence along the south side of the lettuce crop. Whether made with shade cloth or wood, it will provide some breaks from the constant light and reduce stress.
Providing shade is the most practical way to reduce sun stress in lettuce plants, but keeping them cool also helps. A cool spray of water on hot days does the garden good.
While mulching doesn’t provide shade, it does help to keep the soil surface and the roots of your plants moist and cool. This method goes a long way in protecting lettuce plants from too much sunlight and possible bolt.