6 Reasons Why Your Tomato Plant is Wilting and What to Do About It

When it comes to drama in the garden, tomatoes are stars. On the perfect stage, they grow with wild abandon, producing pounds of fruit, but when something is amiss, tomato plants can wilt with gusto. It's not unusual for a tomato plant to appear vigorous and thriving one day and then be a limp collection of stems and leaves the next. Wilt is a sign of stress that needs to be addressed quickly to save the plant. Unfortunately, wilt is often not curable, but it can be prevented. This guide will help you find the cause of wilt in your tomato plant and then take steps to remedy the problem.

1. Drought Stress

Tomatoes have greater water needs than many other garden vegetables. When their water needs are not met, tomatoes will slow their growth and wilt. Tomatoes battling through prolonged drought wilt in the heat of the day and then revive in the cooler nighttime temperatures, only to wilt again the following day. 

Tomatoes require 1 to 2 inches of water per week to thrive. Plants growing in fast-draining, sandy soil grow best when they receive about 2 inches of water a week. Tomatoes planted in well-drained loam or slow draining clay, grow best with about 1 inch of water.

What to do:

Properly water your plants. Too much water is just as problematic as too little water. Before turning on the hose to water your tomato, sink your finger into the soil at the base of the plant. If the soil is moist 2 inches below the surface, don’t water and check the soil again the next day. Water when the soil 2 inches below the surface is just dry to the touch.

When you water, water slowly over a longer period of time. This helps the water seep down deeper in the soil, which encourages plants to develop a deep root system. Always deliver water to the base of the plant; avoid getting the foliage wet, which can encourage some tomato diseases to flourish.

2. High Heat

Tomatoes grow best when the air temperature is below 90°F. Multiple days of temperatures in the nineties combined with dry soil can cause plants to wilt in the afternoon and then recover at night, only to wilt again the following day.

What to do:

Care for the plant well until the high heat passes. Water the plant deeply every few days and fertilize your tomatoes as needed to provide necessary nutrients to maintain strong, healthy growth.

3. Nearby Walnut Trees

Tomatoes growing in the vicinity of walnut trees struggle to survive, often wilting near the end of their life. Juglone, a chemical exuded from the roots of walnut trees, is toxic to tomatoes and many other plants. Walnut tree roots reach far beyond the tree canopy and so does toxic juglone.

What to do:

Grow tomatoes in containers. For best results choose a pot that contains at least 5 gallons of soil. Raised beds are not an option in juglone impacted areas. The toxic juglone will move into the raised bed soil. Removing the walnut tree is not a solution either. Juglone exists for many years in the tree’s decomposing roots.

4. Fungal Wilt Diseases

A well-watered yet wilted tomato plant can indicate one of two common plant diseases caused by fusarium or verticillium. These fungi enter the plant through its roots and block the movement of water and nutrients. Within a few days the infected plant will turn yellow and wilt. Fusarium and verticillium wilt fungal spores overwinter in the soil and infected plant parts and can affect tomato, pepper, eggplant, and potato plants year after year. A telltale sign of fungal wilt is brown streaking just under surface of stem tissue.

What to do:

There is no cure for fusarium and verticillium wilt. Remove and discard infected plants as soon as they are noticed; Do not add them to the compost pile. Avoid destructive fungal wilt diseases by planting resistant varieties. ‘Celebrity,’ ‘Mountain Pride,’ and ‘Quick Pick’ all have resistance to fungal wilt. Crop rotation is another tool in combating fungal wilt. Develop a 4-year crop rotation schedule by planting tomatoes in a new garden spot every year for 4 years and then circle back to the first planting area.

5. Southern Blight

This fungal disease is most often found in southern regions, but can crop up in northern regions during periods of warm, wet weather. Look for signs of southern blight at the base of a wilted tomato plant. If you see cottony white mold in the base of the stem accompanied by tiny light brown fruiting structures, your plant is likely infected with southern blight.

What to do:

There is no cure for southern blight. Remove and discard infected plants as soon as they are noticed. You will need to grow non-susceptible plants in the space for at least 2 years afterwards to avoid spores in the soil infecting new plants. Prevent this blight from taking hold by planting tomatoes seedlings at least 3 feet apart to allow for good air circulation between plants.

6. Bacterial Wilt

Bacterial wilt impacts a tomato plant so fast that it might not have time to turn yellow before it wilts and dies. Identify bacterial wilt as the cause of plant death by cutting open the main stem. If the center of the stem, called the pith, is brown or even hollow, the bacterial wilt is likely the cause of death.

What to do:

There is no cure for bacterial wilt. The disease exists in the soil for many years. Plant tomatoes in a different location for at least 4 years to allow the bacterium to die off naturally.

Tips for Growing Wilt-Free Tomatoes

Healthy tomato plants shake off disease threats and produce pounds of juicy, flavor-rich fruit. Promote healthy tomato plants with these 5 easy strategies.

1. Grow tomatoes in full sun. The planting location should receive at least 8 hours of direct sunlight a day.
2. Select a plant location with well-drained soil. The best soil crumbles easily when dry and clumps together slightly when wet. 
3. Provide 1 to 2 inches of water per week. When it doesn’t rain, water tomato plants by delivering water directly to the base of the plant.
4. Provide nutrients by incorporating well-decomposed compost in the planting area or fertilize plants with a commercial vegetable plant product.
5. Stake plants at planting time. Staked plants dry faster after rain or heavy dew, limiting disease growth.