Why Didn't My Lettuce Develop Well?

Have the seedlings rotted near the soil line and fell over?

Is the plant yellow and stunted and wilts during bright, hot days but recovers at night?

Are there any slender, tough-bodied, segmented worms in the soil around lettuces?

Are the young leaves yellow and distorted?

Are there any oval, light-green to brown insects on the plants?

Are there any clusters of small, sucking insects on the leaves?

Are the leaves yellow?

Has the temperature been above 80°F?

Has it rained a lot lately or were you watering excessively?

Are the leaves pale and the plant stunted?

Are the young leaves dwarfed, curled or twisted?

are the leaves mottled and ruffled?

Do the leaves have yellow or light green spots?

Do the leaves have dark or water-soaked spots?

Did the leaf margins turn brown and dried?

Has the temperature dropped below 35°F?

Does the whole plant collapse or rot?

These symptoms indicate damping-off disease. Keep soil moist, but not soggy. Thin seedlings and spray with compost tea as soon as the first true leaves open to help prevent problems.

Those worms are called wireworms. Adults are dark-colored, elongated click beetles. Apply parasitic nematodes to the soil to control them and avoid planting where the sod was the previous year.

Root-knot nematodes cause enlargements or galls on roots. Control pest nematodes by applying chitin or parasitic nematodes to the soil.

The insects are called tarnished plant bugs. When they feed, they inject a toxin into plants that causes distorted growth. Trap them with white sticky traps. Treat plants with a commercial pyrethrin spray or dust in the evening if the infestation is heavy.

Small insects are aphids. For light infestations, knock pests off plants with a blast of water. Spray plants with insecticidal soap to control or with neem or pyrethrin if the infestation is heavy.

Big vein is a disease that causes light green or yellow, crinkled leaves with lighter, enlarged veins. Infected plants are stunted. Destroy infected plants. Prevent problems by not planting in cold, wet soils or where the big vein has been a problem in the past.

Excessive heat will cause leaves to turn yellow and become tough and bitter. Prevent problems by planting heat-tolerant cultivars and providing partial shade for plants in the heat of the summer.

Waterlogged soil produces the yellow leaves and stunted plant look by damaging roots. Keep soil moist, but not soggy. Plant in raised beds if drainage is a problem.

If the weather is not extremely hot and the soil isn't waterlogged, the problem is probably nitrogen deficiency. Spray plants and drench roots with fish emulsion or fish-meal tea to alleviate symptoms.

Leafhoppers cause pale leaves and stunted look. Treat infested plants with insecticidal soap in the evening or with a commercial pyrethrin spray or dust if the infestation is severe.

Aster yellows cause these symptoms. There is no cure for infected plants, destroy them. Control leafhoppers because they spread this disease.

Mosaic virus causes mottled leaves. Destroy infected plants as soon as possible. Control aphids that spread the disease.

Downy mildew cause yellow or light green spots on leaves. Spray plants with sulfur in the evening to prevent further infection and thin plants to increase air movement.

Various bacteria or fungi cause leaf spot diseases. Destroy badly spotted plants or leaves. Thin plants to increase air movement and avoid wetting leaves when watering.

Temperatures below 35°F cause outer leaf margins to turn tan and leaves to blister. Protect plants with row cover if low temperatures are predicted.

Tipburn is a condition that causes leaf margins to turn brown and dry up. To prevent problems, keep the soil moist, but not soggy and do not allow it to dry out.

These symptoms can indicate the diseases Bottom rot, Lettuce drop or Gray mold. Bottom rot first infects the lower leaves that touch the ground. Lettuce drop affects outer leaves first. Gray mold also starts at the bottom of the plant and turns it into a slimy, brown mess. Destroy infected plants or leaves and thin remaining plants to increase air movement.

If the leaves have holes in them, the culprits might be Flea beetles or caterpillars. Flea beetles make small holes and caterpillars large holes. Use pyrethrin in case of flea beetles and BTK in the case of caterpillars.