Yes, wilting is normal for vegetable plants on days with hot temperatures and full sun. When it gets super hot from 90-100˚ F days in the Front Range of Colorado, lots of plants in the vegetable garden start drooping and wilting, despite having been watered in the morning.
Don't worry, this is normal! (Well, maybe not this crazy heat, but it's normal for plants to wilt on super hot sunny days.)
Plants wilting in the sun is common, and it is caused by the plant losing more water through its leaves than it can absorb through its roots. Plants are smart, and so they wilt to conserve moisture by reducing their surface area exposed to the sun.
Cucumbers above show how wilting is simply due to the hot sun. In the above left photo, you see them wilting in the 89˚ F late morning sun, and on the right is the same cucumber plants later on the same day, after the clouds moved in for the afternoon. Once the sun went behind the clouds, the cucumber plants perked up and looked happy. While this garden bed had been recently watered, on hot sunny days cucurbits will often wilt on due to their shallow roots, which helps to conserve moisture. This is normal and they will likely recover once the the sun gets lower in the sky, clouds roll in, and/or the temperatures drop. You can prevent this by putting shade cloth over your plants on super hot sunny days, but that's a lot of extra work and expense, so not everyone can do this.
All cucurbits – including squash, zucchini, pumpkins and cucumbers – with their shallow root systems, are particularly prone to wilting. Don't fret! As long as the soil is moist, they will recover once the temperatures have dropped later in the day.
Yes, it is normal for vegetable and flower plants to wilt in the sun. This Marigold above is wilting in response to a very hot sunny 100˚F day in Colorado.
This young pepper seedling, above, while it looked fine in the morning, is now wilting in response to a very hot 100˚F sunny day in Colorado.
Some gardeners use shade cloth on super hot days to help prevent wilting and dropping blooms.
Why are my pumpkins wilting in the heat?
While it could mean that they need water (or it could also be caused by bacterial wilt, squash vine borers) most often wilting is normal in the middle of a hot day. If you just watered earlier in the day and the soil is moist, it is completely normal for cucurbits like squash, cucumbers, zucchini and pumpkins to wilt in the heat. These plants have shallow root systems, and wilting caused by heat stress is the way the plants try to conserve moisture by reducing its surface area exposed to the sun. Shade cloth can help if you are able to provide it, though most gardeners do not have the luxury of time and cost to put up shade cloth structures. Just make sure to keep the soil moist as inadequate or inconsistent moisture can cause oddly shaped or poor-tasting fruit. If possible, water your squash, pumpkins and cucumbers with a soaker hose or drip irrigation to keep the soil consistently moist (but not soggy!) and the foliage dry.
So if you have wilting veggie plants, don't fret, it is perfectly normal for vegetable plants to wilt in the heat of the day – even if they are sufficiently watered. If the soil is moist, your vegetable plants and flowers will recover as soon as the sun starts to get lower in the sky and it cools off in the evening. Check your veggies in the evening to make sure that is the case, and also be sure to water if the soil is dry!
But, if it's not just the sunny heat, there are other reasons for Squash Wilting »
Happy gardening! Stay cool out there.
