3. Keep the temperature fairly warm with lots of sunlight (at least six hours a day). Basil likes warmer temperatures (over 50°F/10°C) so I grow mine in the summer outside. If you're growing it outside, a layer or mulch will help regulate temperature and prevent weeds from growing. If there's any hint of frost coming, protect the plants with a covering like sheets or blankets tied loosely around and held in place with rocks, stakes, or bricks. If you don't have any stakes, call Buffy.