Some Herbs In My Garden Have A Sickly Look. What May Have Caused This?

Are the seedlings fall over and the stems are girdled or rotted at soil line?

Are the seedlings clipped off at the soil line?

Are the plants yellow and stunted and the roots have swollen galls on them?

Are the plants wilting and are the roots discolored when you cut-open them?

Are the leaves turning yellow, starting with the older leaves?

Are the leaves yellow and curled and the new growth is distorted?

Are the leaves yellow, plant wilts and stems, crowns or roots are water-soaked and rotted?

Do the leaves have dark, yellow-bordered spots on them?

Are the lower leaves covered with tan, fuzzy growth?

If your seedlings are falling over and the stems are girdled or rotted at the soil line, the most likely cause is a damping-off disease. Damping-off is caused by various soil fungi. Remove and destroy all infected plants. To prevent damping-off let the soil surface dry between waterings, thin seedlings to avoid overcrowding and do not add nitrogen fertilizers until plants have developed leaves.

If the seedlings of your plants are cut off at the soil level, most likely cause are cutworms. These caterpillars can be 1-2 inches long, brown or gray. They feed at night by cutting off young plants and sometimes eating them whole. During the day, they are hidden below the soil surface. Control them by introducing parasitic nematodes to the ground. Using BTK spray on the ground will also control their numbers.

These symptoms usually indicate root-knot nematodes. Other symptoms are plants wilting during bright, hot days. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes.

Likely cause for these symptoms is one of two fungal diseases - Fusarium wilt or Verticillium wilt. There is no cure for these diseases, so infected plants should be removed and destroyed as soon as possible. Don't replant new herbs from the same family of plants in that soil for at least 3 years.

Yellow leaves and stunted plant growth most often indicate nitrogen deficiency. Spray plants and drench roots with fish emulsion to correct. You can also use any nitrogen-rich fertilizer for fast results. Prevent problems by choosing well-drained sites, adding organic matter to the soil to add nitrogen and improve drainage, and by planting in raised beds.

Yellow and curled leaves and distorted growth is caused by aphids. These tiny insects can vary in color, green, pink, black, gray to completely white. They cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and latter leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap, neem oil or pyrethrin should be used with severe infestations.

These symptoms usually indicate one of three fungal diseases - stem rot, crown rot or root rot. These diseases often occur due to poor drainage or overwatering. Remove and destroy infected plants or plant parts. Thin them to ensure good airflow around them. Spray with copper fungicide spray in warm and wet weather. Planting in well-drained soil or raised beds will prevent problems.

Dark, yellow boarded spots on leaves indicate fungal disease - Leaf blight. Spray foliage with fish emulsion or with sulfur to prevent the spread of mild infections.

Tan, fuzzy growth on leaves often indicate fungal disease - Gray mold. Remove and destroy all moldy leaves. Thin plants to ensure good airflow around them and to reduce moisture around leaves. The application of compost tea spray will help in control. Sulfur spray should be used if the disease is severe or the weather is wet and cool.

If the leaves have powdery white patches on their upper surface, most likely cause is a fungal disease - Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.