Tomato Transplants Are Yellowing

Season and Temperature

• Tomatoes are sensitive plants and require warm midspring starts. They yellow and die in frost or temperatures below 55 to 60 degrees Fahrenheit. If outdoor temperatures still fall below this mark, move the seedlings back indoors for protection. Put them outdoors only after temperatures rise to 65 degrees F. Transplant seedlings in the morning to keep the process cool and moist; transplanting at midday leads to root drying and possible death.

Light

• Tomato plants need full, bright sunshine all day. The foliage yellows, wilts and dies in the shade, which also restricts long-term blooming and fruiting. Move the seedlings into sites with six to eight hours of full sun every day, quick drainage and good air circulation. Use stakes and trellis systems to tie up the seedlings and increase sun exposure.

Nutrition and Soil

• Tomatoes may yellow from lack of nutrition, and specifically lack of nitrogen in the soil. Amend the soil before planting with 4 to 5 inches of organic compost to prevent yellowing, and incorporate 8-32-16 or 6-24-24 fertilizer for rooting. Dig compost into the soil around the plants to amend it after planting.

Fertilizer and Water

• New seedlings are sensitive to strong chemicals, and burn to yellow with aggressive or incorrect fertilizer applications. Amend the soil for planting, but avoid further amendments or feedings until midseason. Water the tomatoes with 2 inches of water every week to keep them healthy and growing.