The Leaves on my Cabbage Crops are Changing Color. What is Causing This?

Have the leaves fully changed color?

Have the leaves turned purple?

Have the leaves turned yellow?

Is the whole plant stunted?

Are the stems twisted?

Are the cabbage roots enlarged and clublike?

Are the cabbage roots covered with irregularly shaped galls?

Are there colored spots on the leaves?

Are the spots V-shaped, yellow and appearing on margins of the leaves?

Are the spots yellow-brown and concentrically ringed?

Are the spots pale and is there a white growth on the undersides of the leaves?

Are the leaf spots white-bronze?

Have the tips of your cabbage leaves turned brown?

Purple leaves indicate a phosphorus deficiency. Since phosphorus is not readily available in cool spring soils, spray the plants with seaweed extract to fix the problem.

Yellow leaves and stunted plant growth most often indicate nitrogen deficiency. Spray the plants and drench the roots with fish emulsion to fix the problem. You can also use any nitrogen-rich fertilizer for fast results.

The likely cause for these symptoms is a fungal disease - Fusarium yellows. Leaves of the infected plants will drop off and leave the bare stem. There is no cure for Fusarium yellows, so infected plants should be destroyed as soon as possible. In the future, try planting resistant cultivars like "Applause," "Green cup" or "Red Danish."

Curled yellow leaves are often caused bu aphids. These tiny insects can vary in color, green, pink, black, gray to completely white. They cluster under leaves where they feed on plant sap. Leaves get distorted and later drop from the plant. You can control them by washing them off the cabbage with water spray.

Enlarged and clublike roots are most likely caused by fungal disease - club root. Remove and destroy any infected plants. Keep the pH level of the soil at 7.2 or above to prevent club root fungi activity.

Cabbage roots covered with irregularly shaped galls are caused by root-knot nematodes. Destroy severely infested plants. Solarizing the soil should reduce the number of nematodes in the ground. Planting winter wheat cover crop will also help in prevention.

If the cabbage roots are riddled with slimy, winding tunnels, the cabbage is infested by cabbage maggots. these 1/4 of inch larvae feed on cabbage roots and transfer bacterial and fungal diseases. Remove and destroy infected plants. Solarizing the soil will help reduce maggot infestations.

Yellow, V-shaped spot most likely indicate a bacterial disease - black rot. Infected leaves will die and drop off. Destroy infected plants. Spray copper if the weather is wet and if you had problems with black rot in the past. In the future, you can plant resistant cultivars such as "Blue Boy," "Bravo," and "Fortuna."

Yellow-brown and concentrically ringed spots are caused by fungal disease - alternaria blight. This disease attacks lower leaves first. As the disease progresses leaves and eventually the whole plant will die. Spray plants with copper at the first signs of disease.

White, cottony growths on the undersides of the leaves are caused by fungal disease - downy mildew. Control by spraying plants with a baking-soda-and-soap spray (1 teaspoon baking soda, 1 teaspoon liquid dish soap, 1-quart water) or copper.

White-bronze spots on the leaves are caused by thrips. Thrips are tiny, yellow to black flying insects. They hide under the leaves. Severely infected plant parts should be removed and destroyed. Control thrips by introducing lady beetles or lacewings, their natural predators. Insecticidal soap helps in severe infestations.

Brown to gray spots on the cabbage leaves may indicate a fungal disease - black leg. Other symptoms include stems with sunken areas that enlarge over time. Dead leaves will stay attached to the plant. Spray the plants, especially the stems, with copper at the first sign of disease.

Excessive heat or calcium deficiency may have caused browning of the cabbage leaf tips. Keep soil moisture constant and side-dress plants with compost to provide balanced nutrition.

Poor growing conditions could have caused your cabbage leaves to start changing color. You should plant cabbages in an area that receives full sunlight in a site with fertile, well-drained soil and a pH level between 6.0 and 6.8. Keep soil evenly moist at all times.