|I have planted gerbera daisies in a long window box outside. They are getting a white powdery look to them and they are wilting. They were doing great just a few weeks ago. What can I do to bring them back to healthy appearance?|
|The white powder is most likely powdery mildew, a fungal disease. Powdery mildew fungi spread quickest when the humidity is high and temperatures are between 50F and 90F. To discourage the disease, plant on sites with good air drainage, give the plants plenty of space, water during the morning only, and allow the soil to dry out between waterings. Remove any affected leaves, and if your plant is heavily covered with powdery mildew you should probably remove the entire plant so the infection doesn't spread. For heavy infestations of powdery mildew, sulfur or copper sprays can be applied weekly, starting in July in your area. To obtain these treatments, check your local garden center, and follow the directions carefully.
Gerbera jamesonii or Transvaal daisy is native to South Africa. Gerbera's thrive in full sun and rich soil with excellent drainage. They prefer a thorough watering and then dry soil, followed by a flooding again. The plants need frequent feeding during the growing season and will produce new leaves and flowers if the old leaves and flowers are pinched off regularly.
Gerbera daisies are fussy about watering. Try not to splash water on the crown of the plant. Gerbera daisies like the nightime temperature to be about 60F degrees, and the daytime temperature about 75F. The plant will take full morning sunshine, but appreciates some afternoon shade.
Correcting the environment around your Gerbera daisies should prevent additional problems.