Tomatoes are among the most beloved and rewarding crops for home gardeners and commercial growers alike. Their versatility in the kitchen, nutritional benefits, and the satisfaction of growing your own fresh produce make them a staple in vegetable gardens worldwide. However, despite their popularity, tomato plants are susceptible to a wide range of problems that can significantly impact plant health, fruit quality, and overall yield. In 2026, understanding these common challenges and implementing effective solutions remains essential for achieving a bountiful harvest.

Whether you're a seasoned gardener or just starting your tomato-growing journey, encountering issues like blossom end rot, fungal diseases, pest infestations, and environmental stress is almost inevitable. The good news is that most tomato problems are preventable or manageable with proper care, timely intervention, and knowledge of best practices. This comprehensive guide explores the most common tomato problems faced by gardeners in 2026 and provides detailed, science-backed solutions to help you grow healthy, productive tomato plants throughout the growing season.

Understanding Tomato Plant Health

Before diving into specific problems, it's important to understand what healthy tomato plants look like. Healthy tomato plants have softly fuzzed, medium-green leaves. The stems should be sturdy and upright, flowers should set fruit successfully, and the developing tomatoes should be firm and free from blemishes or discoloration. Any deviation from this baseline—such as yellowing leaves, spotted foliage, wilting stems, or damaged fruit—indicates a problem that requires attention.

In Maryland, tomato plants are susceptible to several diseases, pests, and, at times, unfavorable weather conditions that can disrupt their growth, productivity, and/or eating quality. This reality applies to tomato growers everywhere, making it crucial to develop skills in identifying and addressing problems quickly.

Blossom End Rot: Causes and Comprehensive Solutions

What Is Blossom End Rot?

Blossom end rot is a physiological disorder of tomato in which the tissue of the blossom end of the fruit (the portion of the fruit opposite the stem) breaks down and rots, thus reducing yield. This condition is one of the most common and frustrating problems faced by tomato growers.

Initially, water-soaked spots (resembling small bruises) appear, most often on the bottoms of fruits. Spots enlarge, becoming dark brown to black, sunken and leathery. A nasty-looking, black, bruise-like, water-soaked area, typically on the blossom end (the side opposite the stem) of the tomato. The area grows and becomes sunken and leathery. In severe cases, half the fruit may be affected, rendering it unmarketable or inedible.

The Science Behind Blossom End Rot

Blossom-end rot is caused by a calcium deficiency in the tomato plant. However, this doesn't necessarily mean your soil lacks calcium. Although blossom end rot means that the plant does not have enough calcium within the developing fruit, it does not mean that there is a lack of calcium in the soil.

Blossom end rot is the result of a localized calcium deficiency in the fruit; however, this may not necessarily indicate a calcium deficiency in the soil or in other parts of the plant. Blossom end rot can occur even when calcium levels in the soil are adequate. The problem lies in the plant's ability to transport calcium to the developing fruit.

Calcium only moves in the plant via the xylem and moves with the transpirational water flow from the roots, up the plant and into developing leaves. Calcium has no ability to flow from the leaves via the phloem to the developing fruit. This means that consistent water uptake is essential for calcium transport to fruits.

Factors Contributing to Blossom End Rot

Several environmental and cultural factors can impair calcium uptake and transport:

  • Inconsistent watering: Fluctuations in soil moisture are a primary cause of blossom end rot
  • Root damage: Injury to roots can limit the plant's ability to absorb water and nutrients
  • Excessive nitrogen: Heavy applications of nitrogen fertilizer can interfere with calcium uptake
  • Environmental stress: Hot weather and environmental conditions that cause plants to grow too rapidly
  • Soil chemistry imbalances: The amount of calcium available to the plant decreases rapidly when there is too much potassium, magnesium, ammonium and sodium in the soil
  • Waterlogged or cold soils: Waterlogged or cold soils can inhibit calcium uptake

Preventing Blossom End Rot

Prevention is the most effective approach to managing blossom end rot. Here are evidence-based strategies:

Maintain Consistent Soil Moisture

The most effective way to prevent blossom end rot is to maintain uniform soil moisture. In other words, avoid allowing the soil to dry out in between watering. Maintain a consistent supply of soil moisture. During the growing season, especially as the fruit is developing, tomatoes need at least 1 inch of water per week, supplied as rainfall or irrigation.

Irrigate plants evenly. Tomatoes like consistently moist—not soggy—soil. Consider installing a drip irrigation system on a timer to ensure consistent watering throughout the growing season.

Test and Amend Your Soil

Before planting tomatoes, have your local garden center or Cooperative Extension conduct a soil test. They can give you recommendations to adjust your soil. Check the soil pH. Most vegetables and fruit, including tomatoes, prefer a pH around 6.5.

Have your soil tested periodically to determine if there is sufficient calcium in the soil. If not, add calcium (e.g., bonemeal or lime). However, be cautious: Do not add lime without having your soil tested first.

Use Appropriate Fertilizers

Use fertilizers low in nitrogen, but high in superphosphate, with numbers similar to 4-12-4 or 5-20-5; this will reduce the chances of blossom-end rot. Do not over-fertilize. Tomatoes are heavy feeders, but follow instructions on fertilizer labels, and avoid too much nitrogen.

Protect Plant Roots

Avoid deep cultivation around the plants as much as possible after fruit set, especially in dry weather. Scraping the soil lightly with a hoe is usually sufficient to control weeds in the home garden. Root damage can severely limit water and nutrient uptake.

Apply Mulch

To reduce moisture evaporation from the soil, apply a layer of mulch or pine straw around the plants. Mulching helps maintain consistent soil moisture and temperature, both of which are crucial for preventing blossom end rot.

Choose Resistant Varieties

Select tomato varieties resistant to BER, like Mountain Rouge and Early Resilience. Larger slicer-type tomatoes are usually more prone to blossom end rot than cherry tomatoes, so consider growing smaller varieties if blossom end rot has been a persistent problem.

Treating Existing Blossom End Rot

If blossom end rot appears on your plants, take immediate action:

  • Remove affected fruit: If you see fruit with BER, you should remove the affected fruit. Once a fruit develops BER, it will not regrow or repair the infected area. Remove the fruit; otherwise, the damaged area will serve as an entry point for disease-causing bacteria or fungi
  • Correct watering practices: Immediately establish a consistent watering schedule
  • Apply calcium solutions: If your plants develop BER, drench the soil around their roots with a calcium solution containing 4 pounds of calcium nitrate or calcium chloride per 100 gallons of water (or 4 level tablespoons per gallon of water)
  • Note on foliar sprays: Spraying the plants with calcium has no effect on BER, as calcium cannot move from leaves to fruit

Tomato Blight: Early and Late Blight Management

Understanding Tomato Blight

Blight is one of the most serious fungal diseases affecting tomatoes. There are two main types: early blight and late blight, each caused by different fungal pathogens but both capable of devastating tomato crops.

Early Blight

On tomato foliage, Early blight first appears as circular irregular black or brown spots on the older leaves of the plant. As these lesions enlarge a series of dark concentric rings develop in the center of the spot creating a distinct target pattern. This distinctive "bullseye" appearance is characteristic of early blight.

Over time the tissue surrounding the early blight lesions can yellow and cause the leaves to drop. Severe infestations of this disease can cause 100% defoliation of the plant. Defoliation caused by early blight can reduce fruit yield and can leave the fruit open to sunscald injury.

Late Blight

Late blight is the disease historically associated with potatoes and the Irish potato famine of the mid-1800's. This disease remains a serious threat to tomato crops today.

Infected tomato fruits develop shiny, dark, or olive-colored lesions, which may cover large areas. Complete defoliation (browning and shriveling of leaves and stems) can occur within 14 days from the first symptoms, making late blight particularly devastating.

A combination of daytime temperatures in the upper 70s °F with high humidity is ideal for infection. Fungal spores are spread between plants and gardens by rain and wind.

Preventing and Managing Blight

Cultural Practices

  • Improve air circulation: Allow extra room between the plants, and avoid overhead watering, especially late in the day
  • Water properly: Water at the base of plants to keep foliage dry and reduce humidity around leaves
  • Choose resistant varieties: Selecting varieties that have resistance to diseases such as early blight and Fusarium wilt is one of the most effective prevention strategies
  • Practice crop rotation: Crop rotation is another means to help reduce disease in tomato plantings. Each year, plant tomatoes in a new location away from areas where tomatoes, eggplant, potatoes, or peppers have been grown in the past, since these vegetables all have similar disease problems
  • Maintain proper sanitation: At the end of the growing season, all tomato refuse should be removed and discarded. It is recommended not to use infested vegetable plants in any form to add to a mulch bed or compost bin

Site Selection and Planting

Locate your garden where it will receive morning sun. Morning sun helps dry dew from leaves quickly, reducing the time that foliage remains wet and susceptible to fungal infection.

Purchase certified disease-free seeds and plants. Destroy volunteer tomato and potato plants, as well as nightshade family weeds, such as Carolina horsenettle or black nightshade, which may harbor the fungus.

Fungicide Applications

When cultural practices alone aren't sufficient, fungicides can be used as a preventive measure. Apply fungicides according to label directions, focusing on prevention rather than waiting until disease symptoms appear. Organic options are available for gardeners who prefer non-synthetic treatments.

Common Tomato Pests and Control Methods

Tomato Hornworms

Tomato hornworms are large, green caterpillars that can quickly defoliate tomato plants. These voracious feeders can strip a plant of its leaves in just a few days if left unchecked. Look for large, dark green droppings on leaves as a sign of hornworm presence.

Control methods:

  • Hand-pick hornworms from plants in the early morning or evening when they're most active
  • Encourage natural predators like parasitic wasps, which lay eggs on hornworms
  • Use organic insecticides containing Bacillus thuringiensis (Bt), which specifically targets caterpillars
  • Inspect plants regularly, checking the undersides of leaves where hornworms often hide

Aphids

Aphids are small, soft-bodied insects that may be green, pink, or black, usually found on the young growth of the plant. Aphids suck plant sap and excrete sticky honeydew. Leaf curling, distortion, yellowing are common symptoms of aphid infestation.

Control methods:

  • Introduce beneficial insects like ladybugs, lacewings, and parasitic wasps that feed on aphids
  • Spray plants with a strong stream of water to dislodge aphids
  • Use insecticidal soap or neem oil for organic control
  • Remove heavily infested leaves or plant parts
  • Avoid over-fertilizing with nitrogen, which promotes tender new growth that attracts aphids

Whiteflies

Whiteflies are tiny, white flying insects that congregate on the undersides of leaves. Tomato spotted wilt virus (TSWV) is spread by tiny insects called thrips, which acquire the virus by feeding on one of many infected weeds or ornamental hosts, and then spread it to the developing tomato plants. Similarly, whiteflies can transmit viral diseases while feeding.

Control methods:

  • Use yellow sticky traps to monitor and reduce whitefly populations
  • Introduce natural predators such as parasitic wasps and predatory beetles
  • Apply insecticidal soap or horticultural oil
  • Remove and destroy heavily infested leaves
  • Practice good weed control to eliminate alternative host plants

Spider Mites

Tiny yellow or white spots (stippling); spots can coalesce to cause yellow blotching; leaf undersides may appear dirty. Spider mites can be seen on leaf undersides with the naked eye or using a hand lens. Spider mites suck chlorophyll from leaf tissues, resulting in yellow discoloration.

Control methods:

  • Spray plants with water to increase humidity and dislodge mites
  • Apply insecticidal soap or horticultural oil
  • Introduce predatory mites that feed on spider mites
  • Avoid using broad-spectrum insecticides that kill beneficial predators

Flea Beetles

Tiny round holes (shot holes) in the leaves are the telltale sign of flea beetle damage. These small, jumping beetles are particularly problematic on young plants.

Control methods:

  • Use floating row covers to protect young plants
  • Apply diatomaceous earth around the base of plants
  • Keep the garden area free of weeds and debris where beetles overwinter
  • Use organic insecticides if populations become severe

Additional Common Tomato Problems

Fruit Cracking and Splitting

Concentric cracks that appear in a circle around the stem-end of the tomato, as well as radial cracks that form perpendicular to the tomato stem. Primarily affecting the fruit cosmetically, diseases can also develop in areas with open cracks.

While uneven moisture is the prime culprit for causing cracks in tomatoes—especially during times of rapid fruit growth—many tomato varieties are simply genetically prone to cracking.

Prevention strategies:

  • Water plants consistently. Mulch tomato plants to maintain even soil moisture
  • Reduce watering as tomatoes near ripeness
  • Pick nearly-ripe tomatoes early if heavy rain is forecasted, allowing the fruit to finish ripening indoors
  • Select varieties bred for crack resistance, like Buffalosun, Sunset Torch, and Chef's Choice Orange

Sunscald

White or yellow blisters develop on the side of the tomato facing the sun. Sunscald occurs most often on green fruit. The area may become papery, grayish-white, and flattened. Black mold can grow on the damaged area, causing fruit to rot.

Sunscald occurs when the fruit is exposed directly to the sun, especially in hot weather. Over-pruned plants or lost foliage due to disease exposes fruit to the strong sun rays, blistering the fruit's skin and wall of the tomato.

Prevention strategies:

  • Avoid excessive pruning that removes protective foliage
  • Maintain healthy foliage through disease and pest management
  • Provide shade cloth during extreme heat
  • Choose varieties with good foliage coverage

Blossom Drop

Flower stems turn yellow, and flowers dry up and fall off—leaving a fruitless tomato plant. Blossom drop also affects peppers.

Blossom drop typically occurs during extreme temperatures: when it's either too hot or too cold. Tomatoes prefer daytime temperatures between 70 to 85 degrees Fahrenheit. When summer temps soar over 90 degrees for several days in a row, and nighttime temps remain above 72 degrees, the pollen of self-fertile tomato plants can become non-viable.

Prevention strategies:

  • Wait to plant tomatoes until nighttime temperatures are consistently above 55 degrees Fahrenheit
  • In hot climates, plant tomatoes where they receive a bit of afternoon shade. During heatwaves, cover plants with a 30% shade cloth
  • Water consistently, using drip irrigation
  • Choose early-maturing varieties for extremely hot areas, like Red Torch and Sparky XSL

Leaf Curl and Leaf Roll

Mature tomato plants suddenly curl their leaves, especially older leaves near the bottom. Leaves roll up from the outside towards the center. High temperatures, wet soil and too much pruning often result in leaf roll.

This is a common occurrence in mid-summer and is associated with high temperatures and moisture stress. Some tomato varieties, including heavily pruned determinate-type varieties, are more prone to leaf roll. It does not harm plant growth or yields.

However, Leaves curling upward as if rolling in toward their center can be caused by the tomato yellow leaf curl virus. The disease is transmitted by whiteflies, which can bring it from nearby weeds or other infected crops. It's important to distinguish between environmental leaf roll and viral infection.

Fusarium Wilt

If entire leaves are turning yellow, a likely culprit is Fusarium wilt, caused by the fungal organism Fusarium oxysporum. Lower leaves turn yellow and then brown; leaf and stem wilting with some recovery at night.

Management strategies:

  • Remove infected plants, choose resistant varieties, and sanitize your garden tools. If you have continual problems, try soil solarization
  • Resistant varieties: 'Celebrity Plus', 'Supersweet 100', 'Early Girl', 'Jolene', 'Plum Regal'
  • Practice crop rotation to reduce soil-borne pathogen populations

Septoria Leaf Spot

Septoria leaf spot is a soil-borne fungal disease that only infects tomato leaves and stems. The spots enlarge to 1/8-inch in diameter and are distinguished by a dark brown edge with a white or gray center. The disease spreads from the older leaves upward and can totally defoliate a plant in a short period of time.

Management is similar to blight control: improve air circulation, avoid overhead watering, practice crop rotation, and remove infected plant debris.

Bacterial Diseases

The two most common bacterial diseases of tomatoes in a home garden are bacterial spot and bacterial speck. The bacteria overwinter on crop residue and are seed-borne.

Prevention focuses on using certified disease-free seeds and transplants, practicing crop rotation, and maintaining good garden sanitation.

Damping-Off

The fungi Pythium and Rhizoctonia cause damping-off of tomato seedlings. Seedlings fail to emerge from the soil in the greenhouse, or small seedlings wilt and die soon after emergence or transplanting.

To prevent damping-off, take these precautions: Start seeds indoors in sterilized potting mix and use new or clean containers. Do not start seeds in soil that has a high nitrogen level. Add nitrogen fertilizer after the seedlings have produced their first true leaves. Allow the surface of the soil to dry between waterings.

Cold Injury

This is cold weather injury commonly seen in the early spring when tomatoes, a warm-season crop, experience nighttime temperatures below 35°F. Symptoms include light tan or gray blotches on leaves and stunted growth.

Protect plants with row covers, cloches, or wait until temperatures are consistently warm before transplanting.

Herbicide Drift Damage

Leaves curled, twisted, strappy, distorted, stay small in size. Usually occurs when weed control spray drifts onto nearby plants. Some herbicides can drift many feet from the site of application. Most common with phenoxy-type herbicides (2,4-D) which are used commonly in lawn and agricultural herbicide applications.

Be extremely cautious when applying herbicides near vegetable gardens, and avoid spraying on windy days.

Seedling Problems and Solutions

Most tomato seedling problems come from overwatering, underwatering, insufficient light, or nutrient deficiencies. If you catch them early, almost all seedling problems are fixable.

Yellow Leaves in Seedlings

If the seedling is getting plenty of light (16 hours of light/day is good), transplant it to a larger container with fresh potting soil that contains nutrients. Yellow leaves often indicate nitrogen deficiency or insufficient light.

Purple Leaves in Seedlings

This is very common in new tomato seedlings and transplants. This is caused by a lack of phosphorus and possibly other stress factors. Plants recover when roots are fully established in the garden.

Proper Seedling Care

If you are starting your own tomatoes from seed, there are several keys to preventing disease in tomato seedlings: Use clean potting soil rather than garden soil. You can purchase high-quality soil from most stores.

Carefully control your watering regime. Dryness and water-logging can both make it difficult for plants to take up soil nutrients. I water the seedlings once a day or less, taking my cue from how dry the soil looks (i.e., if the soil is light in color, then water; if it is dark it is still moist and doesn't need more water).

Environmental Stress and Weather-Related Issues

Excessive Rainfall

Too much rain can have devastating effects on tomato plants, leading to reduced yields, lower quality produce, and increased susceptibility to diseases. One of the primary effects of excessive rainfall is waterlogged soil, which can cause the roots of the tomato plant to rot, leading to a decline in plant growth and productivity. Additionally, excessive moisture can create an ideal environment for fungal diseases to thrive, which can further exacerbate the problems faced by the plant.

Excessive moisture can cause the tomatoes to become misshapen, develop cracks, or become more prone to disease. Ensure proper drainage in your garden beds and consider raised beds in areas prone to heavy rainfall.

Heat Stress

High temperatures can cause various problems including blossom drop, sunscald, and leaf roll. Provide afternoon shade during heat waves, maintain consistent moisture, and choose heat-tolerant varieties for hot climates.

Integrated Pest and Disease Management

Follow the links to learn how to manage these problems using integrated pest management and other best practices. Integrated Pest Management (IPM) is a holistic approach that combines multiple strategies to manage pests and diseases while minimizing environmental impact.

Key IPM Principles for Tomatoes

  • Prevention first: Choose resistant varieties, practice crop rotation, and maintain plant health
  • Regular monitoring: Inspect plants frequently to catch problems early
  • Cultural controls: Proper spacing, watering, and sanitation
  • Biological controls: Encourage beneficial insects and use biological pesticides
  • Mechanical controls: Hand-picking pests, using barriers and traps
  • Chemical controls: Use as a last resort, preferring organic options when possible

Best Practices for Healthy Tomato Plants in 2026

Site Selection and Soil Preparation

Tomatoes (Solanum lycopersicum) can be grown on almost any moderately well-drained soil type. A good supply of organic matter can increase yield and reduce production problems.

Choose a location that receives at least 6-8 hours of direct sunlight daily, has good air circulation, and well-draining soil. Amend soil with compost or well-rotted manure to improve structure and fertility.

Crop Rotation

Tomatoes and related vegetables, such as potatoes, peppers, and eggplants, should not be planted on the same land more than once in three years. Ideally, any cover crop or crop preceding tomatoes should be members of the grass family. Corn, an excellent rotation crop with tomatoes, supplies large amounts of organic matter and does not promote the growth of disease organisms that attack tomatoes.

Proper Spacing and Support

Do not crowd tomatoes. Good air circulation around plants is vital in keeping the foliage dry and preventing diseases. Provide sturdy stakes or cages to support plants and keep fruit off the ground.

Watering Techniques

Water at the base of plants using drip irrigation or soaker hoses to keep foliage dry. Water deeply and consistently, providing about 1-2 inches per week depending on weather conditions. Mulch around plants to conserve moisture and regulate soil temperature.

Fertilization

Base fertilizer applications on soil test results. Use balanced fertilizers and avoid excessive nitrogen, which promotes leafy growth at the expense of fruit production and can contribute to various disorders.

Sanitation

Remove any diseased looking leaves as soon as possible. At season's end, remove all plant debris and either dispose of it or compost it properly (hot composting only). Clean and sanitize tools, stakes, and cages before storing for next season.

Variety Selection

One of the smartest ways to protect your crop is to choose tomato varieties bred for resistance to common diseases in your area. Whether you prefer slicers, paste, or cherry tomatoes, many disease-resistant options—hybrids, heirlooms, and open-pollinated types alike—are available.

Look for varieties with resistance codes on seed packets or plant labels. Common codes include V (Verticillium wilt), F (Fusarium wilt), N (nematodes), T (tobacco mosaic virus), and A (Alternaria/early blight).

Diagnostic Tips for Identifying Problems

When trying to identify tomato plant diseases, use these steps: Identify the affected part of the plant — Is it the tomato itself, the leaves, stems, flowers or roots? Note differences — When you compare your tomato plant to a healthy plant, how does yours differ?

Diagnosing them in the garden can be tricky—look closely at the patterns of disease, including which part of the plant shows signs first, how leaf spots develop, the size and location of spots or yellowing, fruit infection, and stem lesions.

Take clear photos of symptoms and consult your local Cooperative Extension office if you're unsure about a diagnosis. Many extension offices offer plant disease diagnostic services.

Resources for Tomato Growers

For additional information and support, consider these resources:

  • Cooperative Extension Services: Your local extension office provides research-based information specific to your region
  • University Extension Publications: Many land-grant universities publish comprehensive guides on tomato production and problem-solving
  • Online Communities: Connect with other gardeners to share experiences and solutions
  • Gardening Organizations: Groups like the National Gardening Association offer extensive resources
  • Seed Companies: Many seed catalogs provide detailed variety information including disease resistance

Conclusion

Growing healthy, productive tomato plants in 2026 requires knowledge, vigilance, and proactive management. While tomatoes face numerous potential problems—from physiological disorders like blossom end rot to fungal diseases like blight, and from insect pests to environmental stresses—most issues are preventable or manageable with proper care.

The key to success lies in understanding the underlying causes of common problems and implementing integrated management strategies. Start with the fundamentals: choose disease-resistant varieties suited to your climate, prepare soil properly, maintain consistent watering, provide adequate spacing for air circulation, and practice good sanitation. Monitor your plants regularly to catch problems early when they're easiest to address.

Simple practices like mulching to block soil splash, pruning for airflow, and watering at the base can help manage or even prevent most tomato leaf problems. Gardeners have battled these challenges for generations—long before modern fungicides—and time-tested habits still go a long way.

Remember that even experienced gardeners encounter problems. The difference is that they've learned to identify issues quickly, understand their causes, and apply appropriate solutions. Keep detailed records of what works in your garden, including which varieties perform best and which management practices are most effective. This knowledge will help you refine your approach year after year.

With the information and strategies outlined in this guide, you're well-equipped to tackle common tomato problems and enjoy a bountiful harvest. Whether you're growing a few plants in containers or managing a large garden plot, the principles remain the same: provide optimal growing conditions, prevent problems before they start, and intervene promptly when issues arise.

For more detailed information on specific topics, consult resources from university extension services, horticultural societies, and other reputable gardening organizations. Happy growing, and here's to a successful tomato season in 2026!