What has gone wrong with my squash, cucumbers, and peas?

January 9, 2013 1:22 PM

Oh no! My winter squash, cucumbers, and peas are failing. Can anybody tell me why and what, if anything, I can do about it? Pictures inside.

In November, my sweetheart and I planted some winter veggies in our community garden. All was well and everything was growing great. The peas in particular were happily producing as much as we could eat, and after some early insect damage from some kind of pentatomid hemipteran everything else was as well. Most of the garden is still doing great; the brussels are sprouting, the carrots are nearing harvest size, etc. However, after coming back from a trip over Christmas, the squash and cukes and peas are all dying back. Here are some pictures of the damage:

Squash/Cucumber Bed
Squash Leaf Closeup
Pea Row
Pea Shoot Closeup

Can anybody tell me what's going on here? Everything else in the garden is fine and the weather has been mild and moist. The affected plants are all in the same corner of the garden but that area is not substantially different from the rest of the plot (it's not in a bowl or anything like that and it gets the same sun). I haven't noticed any insects and the plants are still flowering and trying to produce fruit, especially the squash. Is this a disease of some kind? Some pest I am unaware of? A watering issue? It seems to be getting slowly but progressively worse; can my plants be saved? What should I do?

posted by Scientist to home & garden (15 answers total)

Powdery mildew is my guess, based on that squash leaf. I always had trouble with it when I grew pumpkins & squashes.
posted by lyra4 at 1:24 PM on January 9

Can you get a shot of the underside of a squash leaf?
posted by KathrynT at 1:27 PM on January 9

The peas might just be done but the others definitely look like some kind of mildew. Mild and moist is perfect weather for it unfortunately.

I have had success in the past taking a couple of leaves into my local garden store and asking what they thought it was. You need one of those good shops run by gardeners who know about local conditions and things. I'm also happy to throw fungicide or insecticide onto my plants if it keeps them happy so would generally buy whatever based on their recommendation, but even getting a clear identification can help you look up possible alternative treatments if you don't want to go that way.
posted by shelleycat at 1:30 PM on January 9

Did New Orleans get hit by that odd storm system that spawned tornadoes all over the South right around Christmas (before it came up and dumped a bunch of snow on me in PA)? The squash and cukes are warm-weather crops and would've suffered if it ever got near freezing.

My theory doesn't explain the peas, though.
posted by jon1270 at 1:36 PM on January 9

I agree... Peas look done. Is that summer squash, or winter squash? Even if it's not particularly cold in Louisiana, it may be responding to or compromised by the shorter days. I would contact your local extension office or organic farmers association.
posted by jrobin276 at 1:55 PM on January 9

For the most specific regional information, you might contact your local cooperative extension (there are cooperative extensions all over the country, run by big state land grant universities). The LSU cooperative extension appears to have a "Plant Diagnostic Center" or "Plant Doctor" in each parish who is available to take calls, look at samples, and identify problems for you.
posted by ourobouros at 1:57 PM on January 9

These guys: http://www.lsuagcenter.com/en/administration/about_us/extension/
posted by jrobin276 at 1:58 PM on January 9

+1 for powdery mildew, renowned for destroying cucurbits. Very sorry to say as much, but you may have to pull everything and trash it outright -- no composting, as compost pile temperatures will not kill the spores (which travel on the wind).

Baking soda, diluted milk, and neem oil are often used as preventative measures for powdery mildew and other fungal plant diseases, so you may want to give those a shot before giving up hope. I've tried sulfur and copper fungicides with middling success, albeit at earlier stages in the disease, and have heard good things about Serenade but never used it.
To help prevent similar problems in the future, only water the base of the plant rather than using a sprinkler or watering from overhead (best practice in gardening anyway), space your plants as wide as possible, and grow disease-resistant/tolerant varieties if possible.

You may still be able to wrest a squash or two from your garden, if the fruit is already fully formed and currently ripening on the vine. Any harvest you get from these plants -- which are popping out fruit because they feel they're in danger of shuffling off this mortal coil, last chance to reproduce! -- is 100% safe to eat, although it may be rather bland since the plant is highly stressed and unable to photosynthesize tasty sugars as efficiently as it should.
posted by divined by radio at 2:01 PM on January 9

Winter squash are called that because they're left to mature and stored for use in the winter. They still grow in the summer. Curcurbits need a LOT of warmth and sunshine.
posted by elsietheeel at 2:08 PM on January 9 [2 favorites]

The squash leaves don't look mildewy to me. But the colour of the squash leaves isn't as green as I would expect, even the smaller newer leaves. Nutrient deficiency? Touch of cold weather?
A quick google yields this which would point towards a possible magnesium deficiency -- you're seeing chlorosis and drop of older leaves.
The peas, too -- they should be a little brighter green than they are, and they definitely don't have powdery mildew (you would see it covering the leaves). It looks like they're finishing early but due again to a possible nutrient deficiency?
posted by bluebelle at 2:09 PM on January 9 [1 favorite]

On closer inspection and after comparing with other images online, I am agreeing with the powdery mildew diagnosis. It's a shame that it struck while I was away, as it now looks pretty advances. Still I have culled the worst leaves and will return with a baking soda spray mentioned here and elsewhere on the net as being possibly of some use, and I'll just have to see. Sadly, the forecast is for another ten days of drizzly weather at minimum, so little hope of drying it out.

I'm toing for now with the hypothesis that the peas are just finished. I expected more from them, but they were good while they lasted. At least the rest of the garden is doing well.

Thanks for the advice everyone, it has been invaluable. If anybody has further suggestions I'm all ears.
posted by Scientist at 2:27 PM on January 9

2nding milk. Worked a treat for my mildew.
posted by stephennelson at 3:16 PM on January 9

Gentleman farmer here...if you see leaves start to go pale and the soil is black, like in your photos, your soil is likely saturated and the plants are drowning. Once that happens you'll be plagued with mildew and other diseases as noted above. I'm guessing that there was some considerable rain while you were out of town. I did see some blooms though, so just let that plot dry out a bit and watch it grow and harvest some beauties.
posted by snsranch at 5:50 PM on January 9

The soil is indeed saturated. It has been raining for days and days and will continue to rain for days and days. I hope that the rain will stop and the weather will dry up before the mildew just kills all my squash to death, but I am honestly not optimistic.
posted by Scientist at 7:24 PM on January 9

Maybe work on improving soil drainage after this lot is done to help prevent similar problems next year. I'm not sure what would be the best thing to work in there because it depends on what soil you already have and what the rest of the area is like, but that local extension service thing mentioned above will totally be able to help you.

Vegetable are fun and frustrating at the same time.
posted by shelleycat at 12:33 AM on January 10