The following growing conditions are necessary for the best results when growing tomatoes and eggplants together:
- Soil – Both tomatoes and eggplants require well-drained soil with a pH of 5.5 to 7.5. You can test your soil to determine if it meets the requirements. You can add organic compost or manure to add micronutrients to your soil.
- Watering – These nightshades need regular watering for good production. Soak the soil with one-inch of water each week during your growing season.
- Weed Control – The roots of tomatoes and eggplants are close to the surface, so be careful not to uproot the plants when weeding the garden. Applying mulch made from grass clippings or straw can control weeds without damaging the plants.
Since they both belong to the same family, tomatoes and eggplants are susceptible to the same diseases, such as verticillium wilt and fungal diseases. These diseases live in the soil, spreading into the plants, causing yellow leaves and decreased fruit production. By planting these two plants together, they can infect each other.
Both of these plants grow bushy and tall, so allow enough room between the plants for the air to circulate. Also, make sure the sun can reach all parts of the foliage. This will prevent shady, moist areas where fungus can take hold. At the first sign of fungus, apply an organic fungicide to prevent leaf damage.
Pests, such as flea beetles enjoy feasting on nightshades, so these pests can invade both tomatoes and eggplants. If you plant these two plants together, keep an eye out for pest infestation. You can pick flea beetles off the leaves, or try planting trap crops that attract flea beetles and other insects. Applying a layer of mulch to the soil prevents insect that live in the ground from invading your plants.
Consider the height of tomato plants when planting them with eggplants. Tomatoes grow up to 6-feet tall, and can block the sunlight from reaching your eggplants. Position your plants so they receive full sun at least six hours each day. This prevents excessive shade that can cause excessive moisture around the roots and stems of the eggplants.