7 Reasons Your Tomato Plants Aren't Setting Fruit—And How to Fix Each

Fresh, just-picked summer tomatoes are one of the most versatile fruits in your garden. They're a juicy addition to sandwiches and salads, easy to preserve in sauces and soups, and tasty when roasted and served over pasta. But when you've planted a plot full of tomatoes and have little (or no) fruits to show for your hard work, it's natural for frustration to set in. To learn more, we spoke to a horticulturist about identifying, preventing, and fixing common reasons your tomato plants aren't setting fruit.

Lack of Pollination

Tomatoes are self-pollinating plants, but they need a little help—typically from insects or a light breeze. "Without pollination, there won't be any fruits. Flowers need to be pollinated within two days, otherwise, the flower will dry and drop," says Alison O'Connor, PhD, extension professor of horticulture at Colorado State University Extension in Larimer County. "On hot, windy days, pollination lacks. If temperatures consistently reach above 85 degrees, many flowers will abort."

The Fix

Plant tomatoes in a spot where they can be sheltered from harsh winds and gently shaded from the hottest part of the afternoon, says O'Connor. If you can tell your plants are lacking pollination, help them along. "Gardeners can try to pollinate the fruits themselves by touching a Q-tip from one flower to another, or gently shake the plant (to mimic wind) to get pollen to disperse," she says.

Extreme Weather

Tomatoes thrive in temperatures between 75 and 95 degrees Fahrenheit, and temperatures outside this range can impede their fruit production. "Tomatoes are a bit of a Goldilocks plant—they don't want it too cold or too hot," says O'Connor. "While they are a warm season plant, meaning they grow best in warm temperatures, it can get too hot." When this happens, tomatoes will terminate their flowers and stop efforts to grow and ripen fruits. If it's too cold, tomato growth can slow.

The Fix

Choose a tomato variety that fits your climate; your local nurseries and Extension Offices should have suggestions. "If you're in a cooler climate that has a short growing season, you'll want to pick tomatoes that you can grow from seed to harvest in a short period of time," says O'Connor. "Some climates are not conducive to growing large heirloom tomatoes because it's too short, so cherry tomatoes are a better choice."

Inadequate Light

Tomatoes are full-sun plants, requiring at least six to eight hours of light every day. "Tomatoes love sun," says O'Connor. "If tomatoes are too shady, they can get leggy (stretched and thin) and will produce minimal, if any, fruit." 

The Fix

Select a planting spot carefully, avoiding areas that could be shaded by taller plants. "A north-facing exposure will not provide enough light," says O'Connor, adding that some afternoon shade is fine. "As landscapes mature, trees may cast too much shade, which may require gardeners to move their vegetable garden to a place with more sunlight. Sometimes transitioning to containers is easiest." If you realize after you've planted your tomatoes that they aren't getting enough sun, replant them as soon as possible.

Lack of Nutrients

Properly balanced fertilizer or soil is essential for a plentiful fruit yield. "Tomatoes are considered 'heavy feeders,' which means they grow and produce best when given regular fertilizer (along with optimal growing conditions and regular water)," says O'Connor. Watch for yellow or purple foliage—yellow indicates a lack of nitrogen, purple indicates a lack of phosphorus—or a small, stunted plant.

The Fix

At planting, consider adding a slow release fertilizer to your soil. A soil test can help you determine which nutrients your soil needs. "If you are growing in raised beds and add organic matter each year, consider getting a soil test from a soil testing lab; over-amending can cause poor plant production," says O'Connor.

When adding fertilizer, follow the application directions on the package. "When a plant is lacking nutrients, it's easy to try to fix the problem quickly and add too much fertilizer," says O'Connor. "Take it slow and steady: If the label recommends fertilizing every 14 days, don't do it once a week—this can cause more problems."

Too Much Nitrogen

While the right amount of nitrogen is key to a tomato plant's growth, too much of this nutrient can encourage the wrong parts of the plant to flourish. "Too much nitrogen will result in a very leafy, green, bushy tomato plant with few flowers and fruit," says O'Connor. "The plant puts all of its resources into leaf and foliage production."

The Fix

Choose a balanced, complete fertilizer with a one to one nitrogen, phosphorus, and potassium (NPK) ratio—like 10-10-10—and follow the application directions. "When it comes to fertilizer, more is not better," says O'Connor.

Too Much—or Too Little—Water

Tomatoes need regular, even watering to ensure a bountiful crop. "For the most part, tomatoes are not drought tolerant, and when they receive too little water, you'll see wilting, leaf curl, poor growth, and a lack of flowers," says O'Connor. Watering too much can cause some of the same symptoms, including yellowing leaves, stunted growth, and wilting."

The Fix

In raised beds or in-ground gardens, drip irrigation systems can provide a steady water supply. "Drip irrigation can be run with timers, which makes it much easier for gardeners, [and] may only need to run two to three times per week," says O'Connor. "Containers tend to need daily watering, but getting into a routine can help—drink your morning coffee while you water. If you're an inconsistent waterer, use mulch to help keep soil moisture levels more consistent."

Disease

Tomatoes can be attacked by a variety of diseases, including early and late blight, fusarium, tomato spotted wilt virus, and Septoria leaf spot. "Diseases can be devastating to tomatoes, and they can be very difficult to diagnose," says O'Connor. "There are also disease mimics, such as environmental injury, nutrient deficiencies, herbicide damage, and insects." All of these issues can limit fruit production or prevent it altogether.

The Fix

Plant disease-resistant tomatoes, like hybrids instead of heirlooms, and provide adequate water and spacing. "When watering, always water at the base of the plant to prevent splashing and getting foliage wet," says O'Connor. "Also, be sure to scout and examine your plants on a regular basis to find early detection of insects, which can spread disease, and the start of any unusual symptoms."

If you do find a sick plant, remove it from your garden so it doesn't affect nearby plants. "It's a painful decision, but the best solution," says O'Connor. You should also avoid putting diseased plants in your home compost pile since they typically don't provide enough heat to eliminate the bacteria. "Throw them in the trash instead," says O'Connor. "If you have a confirmed disease, read about it and how you can prevent it in the future."