The desire to maximize garden space often leads home growers to explore companion planting, the practice of growing different crops near each other for mutual benefit. A frequent query involves combining tomatoes (Solanum lycopersicum) and strawberries (Fragaria × ananassa), two of the most popular garden crops. While gardeners hope this pairing will save room, the scientific requirements and biological vulnerabilities of these two plants suggest this combination is not advisable. The potential for shared diseases and competing resource needs outweighs any perceived space-saving benefits.
Why Combination Planting Is Not Recommended
Horticultural experts strongly advise against planting tomatoes and strawberries in close proximity. This recommendation stems from two primary categories of risk that compromise the health and yield of both plants. Attempting to grow them together sets up a conflict that is difficult to resolve without sacrificing the vigor of one or both crops.
The first issue involves their fundamentally different needs for soil composition and moisture, creating a constant struggle for optimal growing conditions. The second, more severe problem is a shared susceptibility to soil-borne pathogens, which can quickly spread and devastate an entire planting area.
Conflicting Environmental Needs
One significant obstacle to co-planting is the difference in the ideal soil conditions for each crop. Tomatoes perform best in a soil environment with a pH range of approximately 6.2 to 6.8, which is slightly acidic to neutral. Strawberries thrive in more acidic soil, with an optimal pH often cited between 5.5 and 6.5. Compromising on a single pH level to suit both crops will result in one, if not both, suffering from nutrient deficiencies.
The water and nutrient demands of these two plants also create difficult management challenges. Tomatoes are heavy feeders that require deep, consistent watering, especially during the fruiting stage. They need a steady supply of moisture to prevent fruit splitting and blossom end rot.
Conversely, strawberries have a shallower root system and prefer less intense watering, as prolonged wet conditions can encourage fungal issues. Trying to meet the high water and nutrient demands of the tomato plant typically results in overwatering the strawberries, making them susceptible to root rot and other moisture-related problems.
Shared Vulnerability to Pests and Pathogens
The most compelling reason to keep these two species separate is their shared vulnerability to a destructive soil-borne fungus. Both tomatoes and strawberries are susceptible to Verticillium wilt, a disease caused by the fungi Verticillium dahliae and Verticillium albo-atrum. This pathogen invades the plant’s vascular system, blocking the flow of water and nutrients, which leads to wilting, yellowing of leaves, and stunted growth.
Planting tomatoes and strawberries together creates a concentrated reservoir for this fungus, allowing it to rapidly build up in the soil. The pathogen can survive in the soil for years as microsclerotia, making the area unusable for other susceptible crops. If one plant becomes infected, the close proximity ensures a swift spread to the other, potentially wiping out the entire bed.
Beyond this specific fungus, the crops share other common pests that thrive in the same conditions. Pests like spider mites and cutworms can easily jump between the adjacent plants, leading to a higher overall pest pressure. Separating the plants geographically is a strategy in preventing the establishment and spread of these shared biological threats.
Recommended Companion Plants for Each Crop
While tomatoes and strawberries should be kept apart, both benefit greatly from being paired with other, more compatible plants.
For tomatoes, basil is an excellent companion, as its strong scent helps repel pests like tomato hornworms and is believed to enhance fruit flavor. Planting carrots or garlic nearby is also beneficial; carrots help break up the soil, and garlic deters spider mites.
Strawberries also have many beneficial planting partners that help improve yield and deter pests. Bush beans are a great choice, as they release nitrogen into the soil, acting as a natural fertilizer. Herbs like thyme and borage also make good companions; thyme helps deter common strawberry pests, and borage repels damaging insects while attracting beneficial pollinators.