In a small home garden, space is often at a premium. You may find yourself crowding together plants or allowing them to mingle with their neighbors just to fit them all in. Sometimes it can be difficult to balance the needs and match the effects of two plants on each other. However, cucumbers and tomatoes grow quite well together.
Cucumbers are considered compatible with tomatoes. The two plants are companion plants, mutually beneficial to each other. Companion plants help one another in several ways, including making it more difficult for pests to adapt to the defenses of a single plant and by providing food and shelter for beneficial insects. Both tomatoes and cucumbers dislike growing near potatoes.
Tomatoes and cucumbers share many of the same basic needs. Cucumbers require 50 to 70 days to reach maturity, while tomatoes need 55 to 105 days, depending on the variety. Both are warm-season crops that require good drainage and a soil pH of 5.8 to 6.5. Because both require deep watering and a consistent supply of water to help fruit develop properly, having the two share space in the garden makes sense.
When planting your tomatoes and cucumbers together, you can opt to let the cucumber vines grow along the ground in the space between tomato plants, or train the vines onto the same supports you use for tomatoes. This mingling of plants is called diversified planting, which the Alabama Cooperative Extension System suggests as a strategy to make it harder for insect pests to find and damage specific crops. Because either crop can develop mold problems under moist conditions and crowding, allow plenty of space for air to circulate between plants.
When growing these two crops together, you must consider the potential for disease. While cucumber mosaic virus does affect both tomatoes and cucumbers, the disease is not limited to these two crops -- it affects more than 40 families of plants. Phytophthora blight is a more serious issue, as it can ravage both cucumbers and tomatoes. Rotate crops to prevent infection, leaving a period of three years between repeat uses of a space for cucurbit and solanaceous crops. When you pair tomatoes and cucumbers in the same space in the same year, that effectively gives you double use of one susceptible area before you have to rotate in another crop.