Common Tomato Issues
|
|
By the time August rolls around, tomato plants start showing their weaknesses. Their heath depends on the weather, how much water they receive, soil drainage, soil and soil health. The variety of tomato is also extremely important as some are prone to certain ailments than others. Check those plant labels when buying tomato plants as they should denote the type of tomato: vine (indeterminate) or bush (determinate), when the tomatoes are produced (early, mid, late season), as well as disease resistance. Letters after the name denote disease resistance: the tomato Quick Pick VFFT. It's resistant to Verticillium Wilt (V), both strains of Fusarium Wilt (FF), Tobacco Mosaic virus (T) and Alternaria or Crown Wilt (A).
Happy Tomatoes
- When purchasing tomato seeds and plants, select resistant varieties, which is often listed on the seed packet or plant label.
- Full sun, at least 6 hours of full-tilt sun per day.
- When planting provide adequate space for each plant. Overcrowding and lack of air flow contributes to diseases.
- Keep water off the plant by watering the ground not the plant.
- Mulch as it keeps holds in soil moisture, prevents the splashing of spores from the soil onto the plant.
- Rotate crops.
Tomato Troubles
yellow leaves: lack of nitrogen. Fertilize with high nitrogen: 5-3-2.
purplish leaves: lack of phosphorous: Apply high phosphorus fertilizer: 3-5-2.
green lush plant with no tomatoes: too shady or too much nitrogen. Provide more sun or apply a high phosphorus fertilizer to stimulate flowering.
flowers fall off: it’s either too hot 30C (85)F or too cold below 12C (55F), or a lack of water. Wait for the weather to improve and water if dry.
wilting during the day but recovers at night: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost.
yellow blotches on lower leaves and they curl inwards: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost.
dark centre inside of stem when severed: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
fruit, if any, are small, yellow and don’t develop: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
one side of the plant and/or leaves are yellow, lower leaves wilt: fusarium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
leaves with watery spots that shrivel and brown: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
brown lesions followed by white growth on stems & under leaves: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
concentric brown rings on lower leaves: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops. older leaves yellow, water-soaked lesions: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
cracked, split fruit: uneven watering. Keep soil evenly moist and don’t let plants dry out between watering.
bottom of fruit rotting: blossom end rot. Lack of calcium & water. Apply dolomite lime & pulverized egg shells to soil. Keep soil evenly moist.
yellow, distorted new leaves and buds with clusters of small insects present: aphids. Wash off with a hose or use soap and water spray. Avoid nitrogen fertilizers.
holes in leaves and fruit: tomato hornworm. Inspect plant and either hand pick them off or spray with Bacillus thuringiensis, a bacterium that only kills caterpillars.
purplish leaves: lack of phosphorous: Apply high phosphorus fertilizer: 3-5-2.
green lush plant with no tomatoes: too shady or too much nitrogen. Provide more sun or apply a high phosphorus fertilizer to stimulate flowering.
flowers fall off: it’s either too hot 30C (85)F or too cold below 12C (55F), or a lack of water. Wait for the weather to improve and water if dry.
wilting during the day but recovers at night: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost.
yellow blotches on lower leaves and they curl inwards: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost.
dark centre inside of stem when severed: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
fruit, if any, are small, yellow and don’t develop: verticillium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
one side of the plant and/or leaves are yellow, lower leaves wilt: fusarium wilt. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
leaves with watery spots that shrivel and brown: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
brown lesions followed by white growth on stems & under leaves: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
concentric brown rings on lower leaves: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops. older leaves yellow, water-soaked lesions: tomato blight. Harvest healthy fruit then discard plant. Don't compost & rotate crops.
cracked, split fruit: uneven watering. Keep soil evenly moist and don’t let plants dry out between watering.
bottom of fruit rotting: blossom end rot. Lack of calcium & water. Apply dolomite lime & pulverized egg shells to soil. Keep soil evenly moist.
yellow, distorted new leaves and buds with clusters of small insects present: aphids. Wash off with a hose or use soap and water spray. Avoid nitrogen fertilizers.
holes in leaves and fruit: tomato hornworm. Inspect plant and either hand pick them off or spray with Bacillus thuringiensis, a bacterium that only kills caterpillars.
Late Blight
|
|
If your tomato plants are not looking healthy, they could be suffering from a disease called Late Blight (Phytophthora infestans), which also affects potatoes. This disease has been around for a while as it was responsible for the infamous Irish potato famine in the 1800’s.
Late blight is quite common in summer. The obvious symptoms appear first on the lower, older leaves. Foliage develops large, brown blotches that soon turn droop, turn a light tan and become crispy. On the stems it appears as brown splotches. The tomato fruit develop dark brown circular spots that become mushy.
As the disease progresses, a white fungal growth appears on affected areas. This disease works quickly and soon entire plants succumb. The best thing to do is to pull out and discard infected plants and certainly don’t compost them.
Fog and morning dew promotes this disease, which we can do little about, however it is prudent not to get the foliage wet when watering. To prevent this disease, water in the morning, rotate crops, especially between tomatoes and potatoes crops. Wait at least a couple of years, preferably four, to ensure there is no cross contamination.
Late blight is quite common in summer. The obvious symptoms appear first on the lower, older leaves. Foliage develops large, brown blotches that soon turn droop, turn a light tan and become crispy. On the stems it appears as brown splotches. The tomato fruit develop dark brown circular spots that become mushy.
As the disease progresses, a white fungal growth appears on affected areas. This disease works quickly and soon entire plants succumb. The best thing to do is to pull out and discard infected plants and certainly don’t compost them.
Fog and morning dew promotes this disease, which we can do little about, however it is prudent not to get the foliage wet when watering. To prevent this disease, water in the morning, rotate crops, especially between tomatoes and potatoes crops. Wait at least a couple of years, preferably four, to ensure there is no cross contamination.
Cracked Tomatoes
|
Uneven watering is the reason why cracks appear in tomato fruit. Dry soil followed by a thorough soaking makes the tomato fruit to grow too fast; too fast for its own skin. Thin skinned tomato varieties are especially prone to this condition. Try to keep the soil evenly moist.
Container grown tomatoes benefit greatly from having a large drainage tray underneath them. A 3 inch layer of mulch on top of the soil, even ones in containers, helps to keep soil moisture more constant. |
Blossom-End Rot
|
Blossom-End Rot appears on the bottom end of the tomatoes. It becomes flattened or sunken, brown and leathery. This is not a disease, but a lack of calcium in the soil. The two main reasons why the plant cannot absorb calcium are inconsistent watering and soil that’s too acidic.
Inconsistent watering, especially drought, prevents the distribution of calcium throughout the plant. Tomato plants grown in containers often suffer this malady as keeping the soil consistently moist is tricky during the heat of the summer. |
Soil that is too acidic also prevents calcium absorption. Tomatoes prefer a pH of 6.2 to 6.8. Add dolomite lime to increase soil pH and as an added bonus, the lime also contains calcium. Work the lime into the soil, following the manufacturer’s instructions, then water well. Crushed eggshells mixed into the soil is also a great idea. Add them to your compost bin and apply the finished compost to your veggie beds and containers yearly.
To prevent this condition check soil pH in spring and apply dolomite or dolopril lime according to direction. Apply a mulch, keep soil evenly moist, avoid soil from drying out, avoid high nitrogen fertilizers as it ties up the calcium in the soil and avoid hoeing close to roots. If growing in pots, make sure the container is larger enough that it doesn’t dry out repeatedly and include a good sized drainage tray.
To prevent this condition check soil pH in spring and apply dolomite or dolopril lime according to direction. Apply a mulch, keep soil evenly moist, avoid soil from drying out, avoid high nitrogen fertilizers as it ties up the calcium in the soil and avoid hoeing close to roots. If growing in pots, make sure the container is larger enough that it doesn’t dry out repeatedly and include a good sized drainage tray.
Verticillium Wilt
|
|
Wilting tomato plants may not be thirsty; they may be infected with the fungal disease, verticillium wilt. A good indication that the wilting is due to this disease and not a lack of water is moist soil (duh). Often only one side of the plant is affected and the plants recover at night.
Look for yellow blotches on the lower leaves that may curl inwards. As the disease progresses, the leaf veins turn brown followed by dead spots. This fungi prevents water from translocating throughout the plant and contains a toxin that kills and starves plant tissues as it spreads. Plants not only wilt and discolour, they become stunted and fruit, if any, are small, yellow and don’t develop. A good indication of this disease is inside the stem. If it has a dark centre when severed, it is verticillium wilt.
Tomatoes are not the only vegetable prone to this disease. All members of the tomato family are vulnerable: potatoes, peppers and eggplants (aubergines). Once a plant is infected toss it in the garbage as there is no control.
Look for yellow blotches on the lower leaves that may curl inwards. As the disease progresses, the leaf veins turn brown followed by dead spots. This fungi prevents water from translocating throughout the plant and contains a toxin that kills and starves plant tissues as it spreads. Plants not only wilt and discolour, they become stunted and fruit, if any, are small, yellow and don’t develop. A good indication of this disease is inside the stem. If it has a dark centre when severed, it is verticillium wilt.
Tomatoes are not the only vegetable prone to this disease. All members of the tomato family are vulnerable: potatoes, peppers and eggplants (aubergines). Once a plant is infected toss it in the garbage as there is no control.
Early Blight
|
This common fungus first appears as dark spots on foliage that become a circle within a circle (concentric). Soon the entire leaf turns yellow, die and fall off. Stems and fruit are also affected. Fruit have black shiny lesions. To prevent early blight, grow resistant varieties, rotate crops and keep foliage dry. There’s no sure-fire control so discard the plant and don’t compost it.
|
Preventing Diseases
One of the major ways tomatoes plants become infected with disease is by contaminated soil. This is why it is important not to grow tomatoes in the same place year after year and any of their relatives: potatoes, peppers and eggplants.
When a plant becomes seriously infected, harvest any decent tomatoes, then discard the plant. Remove all the plant parts from the area so they don’t re-contaminate the soil. Don’t put them in the compost.
Rotate your crops. Don’t plant tomatoes, potatoes, eggplants and/or peppers in the same bed for at least 4 years! This is why I had to make another veggie bed, just so I could rotate my crops more efficiently.
Plant tomatoes in well-drained soil and don’t overwater as this encourages this disease. Just one day of saturated soil will incur infection especially if combined with cool soil: 13°C (55° F).
Plant resistant varieties. When purchasing tomato seeds and tomato plants look for the initial V at the end of the tomato’s name: Tomato - New Yorker (V). This indicates that the variety is resistant to verticillium wilt. That doesn’t mean it will not become infected if it is grown in contaminated soil. And, if all else fails, solarize the soil.
When a plant becomes seriously infected, harvest any decent tomatoes, then discard the plant. Remove all the plant parts from the area so they don’t re-contaminate the soil. Don’t put them in the compost.
Rotate your crops. Don’t plant tomatoes, potatoes, eggplants and/or peppers in the same bed for at least 4 years! This is why I had to make another veggie bed, just so I could rotate my crops more efficiently.
Plant tomatoes in well-drained soil and don’t overwater as this encourages this disease. Just one day of saturated soil will incur infection especially if combined with cool soil: 13°C (55° F).
Plant resistant varieties. When purchasing tomato seeds and tomato plants look for the initial V at the end of the tomato’s name: Tomato - New Yorker (V). This indicates that the variety is resistant to verticillium wilt. That doesn’t mean it will not become infected if it is grown in contaminated soil. And, if all else fails, solarize the soil.
But Wait...There's More...
For more information on growing vegetables click on the links below:
- Spring Veggie Gardening
- Crop Rotation, Succession and Companion Planting.
- Taming Tomatoes
- Speeding Up Tomato Harvests
- Tomato Tips
- Tomato Troubles
- Tomatoes Seedlings to Plants
- Growing Potatoes
- Harvesting
- Winter Veggie Gardening
- Building a Potager (French Kitchen) Garden
- How to Build an Easy Veggie Garden Trellis
- Plant Pests Part 1
- Plant Pests Part 2: Controlling Insects
- Slugs & Snails
- Growing Seeds Indoors
- Growing Seeds Outdoors
- Soil Building
- Compost Tea
- Composting
- Fertilizing & Feeding Plants