I am trying to grow some basil for cooking but the leaves are turning brown and black. I have checked and I have found no bugs and I do not over water or under water.
Basil is one of my favorite summer herbs and it is a snap to grow if you get the conditions right.
It is a tender annual that should be planted after the last frost date in your area. Cold temperatures will cause the leaves to blacken and turn to mush. Depending on when you set your plants out, this may be the cause of your problem.
The key to growing basil is to giving it plenty of sun (6 to 8 hours) and well-drained soil. Mother nature usually provides enough water for basil but water deeply weekly during dry spells. Plants grown in containers dry out faster so they will need to be watered more frequently. Avoid splashing the leaves when watering.
Basil requires very little fertilizer. I apply fish emulsion or a 05-10-05 fertilizer diluted to half strength once, maybe twice during the growing season.
For the best flavor and to promote a bushier plant, keep the blooms pinched back. And remember the more of those delicious leaves you harvest, the more the plant will produce!
Fungal problems may also cause black or brown patches to form on leaves, especially if you are experiencing a wet spring. Make sure your plants have plenty of good air circulation and treat them with a commercial fungicide that is safe to use on foods.