Oboegirl
Newly Registered
Posts: 9
Joined: Wed May 27, 2015 9:10 pm

Need help with white powder mold

Every year powder mold gets our zucchini and squash. I hate to use chemicals but we have had very few zucchini the last couple of years. We tried Serenade last year but it didn't really help. We have tried moving the plants to a different area but I would like to do something to stop the mold from taking hold. Any suggestions?

Thank you,
Oboegirl

bri80
Senior Member
Posts: 282
Joined: Sat Nov 19, 2016 5:12 pm
Location: Portland, OR

Where are you located? What is the weather (temp, humidity) like, typically? How much do you water?

If you're talking about powdery mildew, my experience is healthy, strong plants don't succumb to it. Stressed, weak plants do. Sometimes this happens just because it's the end of the growing season and the plant is weak from putting out so much fruit. But if it's in the middle of the growing season, and you're not getting many fruits, your plant is stressed/weak for some reason.

A lot of times, I think it's due to UNDER watering. People think, "It's a fungus, caused by too much moisture on the plants, so I'll water less." Squash have very shallow root systems that spread laterally along with their foliage, so they're only taking water from the top few inches of soil. If that soil dries out, the plant is dehydrated, stressed, weakens, and succumbs to powdery mildew. The gardener thinks, "Well, there must have been too much moisture for some reason." and the cycle continues next time.

So without more details about how you are growing your plants, it's difficult to say, but I would focus on these things and see if you just don't have a problem this year (at least until the end of the growing season):
1) Give them enough space. They get huge. They need space.
2) Water more frequently but not as deeply. Use soaker hoses if you don't want to get the foliage wet.
3) Make sure you add a large amount of high-quality, slow-release organic fertilizer to the soil before you plant. I recommend any of Down to Earth's seedmeal-based fertilizers (you can order them from various places online if you can't find them locally, I use the vegan blend). Add lime if your soil needs it, and spread at 1-1.5 gallons per 100sq ft. Dig it into the soil with some compost, then plant.

I think you'll find you'll have super healthy, strong plants that don't succumb to disease until AFTER they've given you more zukes than you can eat.

Oboegirl
Newly Registered
Posts: 9
Joined: Wed May 27, 2015 9:10 pm

Hi, Thank you!

We are in southern Wisconsin. This year when we planted our zucchini we added Espoma Gardentone, bone meal, compost and earthworm castings to the holes. The past two years it seems like we get lots of flowers and a few tiny fruits and then the powder hits (midseason) and the fruit dies. We had 6 plants and maybe got 2-3 zucchini the whole season. We water every morning with a wand and try to keep the moisture from getting on the foliage. The first year we did have them planted very close together (4x4 style) and last year we gave them more space. This year we planted 4 per box. Also, I'm questioning the source of my plants. We buy them from a local greenhouse at the beginning of each season and I needed some more herbs so I went back yesterday and noticed that all their zucchini babies were already covered in mold. I'm wondering if I should pull the plants I already bought from them and try a different source. We had late winter and only got our plants in the ground a couple of weeks ago. Last year we tried the milk and baking soda spray and didn't get a very good yield. Thank you for your suggestions and if you have more advice I'm all ears!

Oboegirl

bri80
Senior Member
Posts: 282
Joined: Sat Nov 19, 2016 5:12 pm
Location: Portland, OR

I would suggest just growing them from seed. I just planted my summer squash and they have just emerged, you should have plenty of time (I'm not sure about winter squash varieties for where you're located, you'd have to ask someone with local knowledge). Nursery seedlings are often weak and maltreated. Seed-grown in your own garden is way better, any time you can do it.

Also, your description of tiny fruits dying makes me think your flowers are not getting pollinated. Zucchini/summer squash requires pollinated female flowers. I do it by hand, because I don't trust the bees to always be on it. Locate your female and male flowers - female flowers have a small bulb underneath the flower on the stem - this is the immature fruit. Male flowers are on long, non-bulbous stems. Pick off a male flower, remove the petals so you can get to the pollen in the middle, and spread it around inside the female flower, makes sure you get pollen from the male all over various parts in the center of the female. Or use a feather or something to transfer the pollen. I bet you'll see better results.

bri80
Senior Member
Posts: 282
Joined: Sat Nov 19, 2016 5:12 pm
Location: Portland, OR

I should mention that the flowers only open for a few hours in the morning, so you have to pollinate in that window.

Oboegirl
Newly Registered
Posts: 9
Joined: Wed May 27, 2015 9:10 pm

Thank you, I'll definitely try that! I've got tons of bees in my area but I'll try anything I can at this point. I appreciate your help.

Oboegirl.



Return to “Organic Gardening Forum”