Strong plants are less susceptible to infection. Ensure your herbs have plenty of air and space to grow on without exhausting their water or nutrient supplies and provide shade if the sunlight is too strong. Remove infected or severely damaged plants immediately. Burn diseased material and do not reuse spent compost.
These and other tools are used throughout the garden and can carry fungal and bacterial infections from one plant to the next. Try to clean the blades of your pruners at the end of each day using a cloth soaked in domestic disinfectant. When pruning diseased material, wipe the blades before moving on to the next plant.
This need not just include synthetic pesticides, which could be harmful to wildlife. Careful use of foliar feeds and preventative natural extracts can be helpful. If using a licensed chemical product, identify the pest before application following the manufacturer’s instructions—your herbs are, on the whole, an edible crop.
This disease is exacerbated by dry soil and humid air. Infected leaves may become yellow and distorted. Control by removing infected material and reducing overhead irrigation. On non-edible crops, use a licensed fungicidal spray.
Most commonly seen on mint, small orange-brown fungal spore pustules occur on the stems and leaf undersides, sometimes accompanied by leaf distortion in the spring. Destroy infected plants and do not reuse the potting compost.
This does not always indicate a pest or disease. Natural and synthetic pesticides and herbicides can cause damage, even in very small doses. Sprayed green waste can be composted but it is only reliably safe to use after a number of years.
This occurs to young seedlings and can look like wilting. The cause is a fungal infection that thrives in damp, airless, low-light conditions. Prevent it happening by only using clean materials and germinate seeds in light, airy conditions at the correct temperature.
Ants are not really a problem in the herb garden, but they can be an irritant. They are, however, a useful indicator as they scurry over the stems of plants where an aphid colony is developing. The ants \"farm\" the aphid honeydew and protect them from other predators.
Too much rain, irrigation, or poor drainage will severely damage and even kill many herbs, but it is easy to mistake the superficial symptoms for drought. Inspect the root system to determine which is the problem. Some plants will recover with repotting.