Common Summer Garden Problems


This time of year, the summer planting season is winding down and we are now into weeding and maintenance mode.  The big push to get plants in for summer colour is done. Now it’s time for filling in empty spots and popping in fresh colour. Vegetables are flourishing and it’s time for fall planting of veggies. But in the meantime, we are faced with some seasonal issues like powdery mildew!

Powdery mildew is a fungal disease that occurs when conditions are optimal. White or gray spots appear seemingly overnight on plants that looked previously healthy. The perfect storm for powdery mildew is, dries foliage, high humidity and low light. Powdery mildew will often cover the entire plant, stems, flowers and sometimes fruit. In advanced cases it can cause plant defoliation, curling and browning of leaves, premature bud drop and reduced flower quality. It will not necessarily transfer to other plants, but if the conditions are right, most trees and plants can succumb to powdery mildew. Fortunately, it is rarely fatal to the plant, and control is relatively easy.

If you notice signs of powdery mildew you have a few options to try. Making sure that plants have sufficient light and good air circulation will be the best way to help prevent powdery mildew. Skim milk mixed 1 part milk to 2 parts water is a natural way to fight this fungus. Enzymes in the milk help break down the fungus without harming beneficial bugs, mammals or humans. It is important to only use SKIM/FAT FREE milk as the higher milk fat content does not have the same effect and will often smell sour if used. Both options are effective but need to be used carefully as it can damage new tender growth.

Some other commercially available organic controls for powdery mildew are;

  • Bonide Liquid Copper Fungicide – Available in a ready to use spray, or concentrate, that contains Copper Octanoate (copper soap) and is effective on powdery mildew, black spot, downy mildew and early blight. Safe for edible crops:
  • Serenade Disease Control is a biological product which means it contains live strains of Bacillus subtiis that actually help destroy the fungus. It is also available in a ready to use or a concentrate, and is safe for organic gardening and edible crops up to the day of harvest:
  • Neem Oil is another organic measure for powdery mildew, rust, blackspot, aphids, whiteflies and a host of other insects and pests. It can also be used as a dormant spray to help control overwintering of eggs and insects.

Powdery mildew will not kill your plant, but it can lessen your success and make control difficult. Proper sun exposure and prevention are your best defense against this problem. So go poke around your garden and see what you can see!  Happy Gardening 🙂


Listed below are a few home remedies that you could try.

  • Baking soda and water combined with dormant oil and insecticidal soap (1 Tbsp baking soda, 1 tsp dormant oil, 1 tsp insecticidal or liquid soap-not detergent- to 1 Gallon of water).
  • Potassium Bicarbonate eliminates powdery mildew once it has started, as Potassium Bicarbonate is a contact fungicide that kills the spores quickly. This option is also organic.
  • Mouthwash, 1 part mouthwash to 3 parts water
  • Cider vinegar 2-3 Tblsp to a gallon of water