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Ten Common Tomato Problems

You spend countless hours caring for your tomato plants, trying to make sure they have enough water and light, but suddenly the plant has black splotches, funky leaves, low yield, or something else. What could possibly have happened? All-America Selections put together a list of the 10 most common problems in tomato plants and how to solve them!

Top 10 problems

  1. Blossom-End Rot (BER)
  2. Blossom Drop
  3. Cracked Fruit
  4. Sunscald
  5. Poor Fruit Set
  6. Cat-Facing
  7. Yellow, Spotty, Wilted Foliage
  8. Dark Spots on Fruit
  9. Leaf Roll
  10. Nibbled Fruit

Blossom-End Rot (BER)

Blossom-End Rot is a nasty-looking, black, bruise-like water-soaked area, typically on the blossom side (the side opposite the stem) of the tomato. It is caused by a lack of calcium in the fruit. Some solutions include:

  • Checking the soil pH: most vegetables and fruit, including tomatoes, prefer a pH around 6.5.
  • Avoid planting tomatoes too early: cold, wet soil can damage roots and root hairs, leading to BER.
  • Do not over-fertilize: tomatoes are heavy feeders, but follow instructions on fertilizer labels and avoid too much nitrogen.
  • Irrigate plants evenly: tomatoes like consistently moist – not soggy – soil

Blossom Drop

Blossom drop is identified by flower stems that turn yellow, and the flowers dry up and fall off – leaving a fruitless tomato plant. It typically occurs during extreme temperatures: when it’s either too hot or too cold. Some solutions include:

  • Avoid planting too early: wait to plant tomatoes until nighttime temperatures are consistently above 55 degrees Fahrenheit.
  • Water consistently: it may be best to use drop irrigation to water
  • Fertilize: select a fertilizer ideal for tomatoes, avoiding excess nitrogen.

Cracked Fruit

Cracked fruit looks like 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. Causes include uneven moisture and genetics. Some solutions include:

  • Water consistently: reducing watering near ripeness can also help
  • Mulch: adding mulch helps to maintain even soil moisture

Sunscald

Sunscald looks like white or yellow blisters that develop on the side of the tomato facing the sun, most often occurring on green fruit. It occurs when the fruit is exposed directly to the sun, especially in hot weather. Solutions include:

  • Maintaining healthy plants and foliage: over-pruning plants or lost foliage due to disease exposes fruit to the strong sun rays.
  • Water regularly and consistently: avoid splashing water on the leaves, which can lead to foliar disease.
  • Mulch: mulching helps to maintain soil moisture and to avoid soil splashing on leaves when watering, which can lead to disease.

Poor Fruit Set

Poor fruit set looks like plants producing few to no tomatoes, often occurring on large-fruited heirloom varieties. It can result from blossom drop, high temperatures, extreme humidity, or too much nitrogen. Some solutions include:

  • Stagger planting: staggering planting helps to increase the odds of successful fruit sets throughout the season.
  • Apply fertilizer: apply tomato specific fertilizer according to the directions on the label.

Cat-Facing

Cat-facing is brown creases and folds that form on the blossom end of the tomato creating an unattractive – but still edible – fruit. Environmental conditions like long periods of cool daytime temperatures and nighttime temperatures can cause abnormal development of plant tissue. Some solutions include:

  • Avoid planting too early: wait to plant tomatoes until the temperatures warm to avoid damage to flowers.
  • Avoid excessive pruning: this will help reduce the plants exposure to disease

Yellow, Spotty, Wilted Foliage

This can be identified when the lower leaves turn yellow, or the plant experiences an overall yellowing/wilting of foliage, which can lead to foliage drop. The culprits may be invisible to the naked eye because they may be fungal, bacterial, or viral. Some solutions include:

  • Remove yellow foliage: this helps reduce or eliminate the spread up the plant.
  • Mulch: mulching helps to avoid soil splashing on leaves when watering, which can lead to disease.

Dark Spots on Fruit

This looks like ripe fruits the develop ugly, sunken, black, or brown spots. It is often caused by a nasty pathogen that lurks in the soil with its spores splashing onto the plants. Some solutions include:

  • Trellis the tomatoes: reduce the likelihood of soil splashing on plants when watering.
  • Use drip irrigation: helps to avoid soil splashing on the plant when watering
  • Mulch: mulching helps to avoid soil splashing on leaves when watering, which can lead to disease.
  • Apply fungicides: prevents the spread to other plants

Leaf Roll

Leaf roll is when the tomato leaves curl either up or down, instead of presenting normally. Causes can be tricky to diagnose because many factors can cause it: physiological (cultural or environmental factors); viral infection; or herbicide damage. The solution depends on the cause, but herbicide damage cannot be reversed.

Nibbled Fruit

Nibbled fruit is damage from a garden pest, from deer and birds to hornworms and slugs. Some solutions include:

  • Check plants daily: if you see eggs or pests, promptly remove them.
  • Attract beneficial insects: they can help with the pest problem with minimal pesticide usage

For more information on these common problems, including additional solutions to them, click here.