Powdery Mildew

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Author Message

Lorraine Ciarallo

From my squash to my boutiful kale, powdery mildew is everywhere. Is the kale trash or can it be rinsed off and eaten? What's the best way to deal with it next season besides buying more resistant seeds. Thank you.

Tuesday 16 August 2011 09:46:35 am

C Zyha

I had the same problem with my kale. I think I planted them too close together and fed the soil a little too well. It made me cry to pull them out. Such potential, gone! They were beautiful and lush. I tried washing them off, but they still smelled of mildew so I composted them. Now of course I'm wondering if I shouldn't have garbaged them instead. sigh.

Tuesday 16 August 2011 06:32:28 pm

Barbara Kuhne

I'm also wondering whether composting squash plants with mildew is a good idea. Does anyone know?

Tuesday 16 August 2011 06:51:22 pm

Linda Gilkeson

Powdery mildew is a problem this time of year on a variety of vegetables and flowers as the cooler, more humid nights make ideal condition for spread. Different species of fungi cause the disease we call 'powdery mildew' so the mildew on squash is different from what you are seeing on kale. Unlike other kinds of fungi, powdery mildew fungi thrive in high humidity, but spores can't germinate in water--so rainy weather or overhead irrigation systems help supress it. You can spray leaves of affected plants with water in the morning every couple of days to wash spores from the leaves and slow the spread of the disease. There are other sprays an organic gardener can use, but water works as well as sulphur, baking soda, etc. so I would stick with water. It is fine to compost mildewed plants and leaves.
There is a complication, however (ain't there always!), because on the kale, spinach and some other plants, the whitish or bluish powdery coating on leaves might be caused by different fungi, which cause 'downy mildew'. These fungi spread in wet conditions.
As you suggested, next year, look for resistant varieties when choosing crops.

Wednesday 17 August 2011 09:19:46 am

EJ Hurst

Can you still eat plants that have had mildew on them?

Thursday 18 August 2011 03:22:27 pm

Linda Gilkeson

Hi EJ,
Squash, apples, strawberries, etc. from plants that have powdery mildew on the leaves are OK to eat. Edible leaves with mildew wouldn't be a good idea--it is never a great idea to inhale fungal spores of any kind and I expect the flavour would be off too.

Thursday 18 August 2011 04:00:51 pm