How to Avoid Common Squash Problems

, written by Benedict Vanheems gb flag

Perfect winter squashes

Squashes are a staple in many gardens, yielding versatile fruits to spark our culinary creativity. They’re rapid, vigorous growers, but that doesn’t make them entirely trouble-free. Read on or watch our video to discover tips and tricks to get your squash safely over the finishing line, ready to harvest...

Keep Your Squash Plants Healthy

By now your squash should be a riot of lush, healthy foliage. Maintain this steady growth by watering very thoroughly whenever its dry – squashes love moist soil and will respond accordingly.

Remove any weeds that manage to poke through, and top up mulches using organic matter such as garden compost to help roots stay cool and moist. To keep plants tidy, cut off any dead, shriveled or yellowing leaves.

Squash bugs (left) and squash vine borers are two major pests to keep a lookout for

Squash Pests

Two troublemakers in particular will often pay your squashes an unwelcome visit - squash bugs and squash vine borers.

Squash bugs feed on sap, weakening plants and threatening fruit production. Protect plants when they are most active early on in the summer by using row covers, then continue to check for eggs at least twice a week. Rub or scrape off the eggs. Adult bugs can be knocked or shaken off plants into a bucket of soapy water, or if you keep chickens, offer them as a tasty treat.

Squash vine borers are found in the eastern half of North America. They burrow into stems, causing them to rot and foliage to wilt. Like squash bugs they’re most active earlier in summer. Row covers can help keep them off or wrap stems in foil to prevent the adult moths from laying their eggs at the base of plants. It’s possible to cut the grubs out by making vertical cuts into the stem using a sharp knife. Once you’re done, bury the stems with moist soil to encourage new roots. Or try growing butternut squash, which is less likely to be troubled by squash vine borers.

Prevent powdery mildew using a dilute milk spray

Powdery Mildew

Powdery mildew is a common fungal disease that forms a white, powdery coating on both sides of the leaves. In the worst cases it will stall growth by preventing the leaves from absorbing enough sunlight.

A common reason behind powdery mildew is irregular watering. This stresses plants, leaving them susceptible to infection, so keep plants well-watered.

If plants do become infected remove affected foliage straight away. A great way to prevent powdery mildew altogether is to mist leaves with a solution of one-third milk to two-thirds water. Spray the milky mixture onto all surfaces, early on a dry, sunny day. Repeat every ten to 14 days throughout the growing season. This milk-water solution can also be used to treat mild infections.

Create a sling to prevent heavy squashes breaking off the vine

Support Your Squashes

Fruits left to swell on the ground can develop blemishes or even rot in wet weather. A simple way to prevent this is to slip a tile or slate under the young fruits as they begin to swell.

Sprawling varieties of squash look stunning trained up vertical supports such as trellising or arches. Be mindful though that vines can potentially tear or collapse under the weight of heavy fruits. Minimize this risk by tying a sling into place for each fruit. Use any old fabric to make them – old pantyhose, as shown in the image above, are perfect.

Harvest squashes with care to make sure they store in top condition

Harvesting Squashes

Summer squash are harvested the moment they reach a useable size. Just cut them free and store in the refrigerator for up to a week.

Winter squash and pumpkins – essentially a type of winter squash – are ready as early autumn passes to mid-autumn. You’ll know they are ready because the skins will have hardened so that they can no longer be scratched or pierced with a fingernail. The stems will also have toughened up and the foliage will be starting to die back.

Cure squashes somewhere warm and dry before storing

Storing Winter Squash

Winter squash need to be cured before storing to drive off excess moisture. If it’s dry, just leave squashes and pumpkins where they are, to cure outside in the sunshine. If it’s wet or turning colder, bring them inside to finish curing somewhere warm and dry – on a slatted greenhouse bench, for example.

Start by cutting back some of the foliage so you can clearly see the fruits. Now cut them free with a sharp pair of pruners, retaining some of the main stem either side to leave a T-shaped stalk. Cup fruits when carrying them; never hold a fruit by its stem or it might snap off, exposing the flesh to infection.

After diligently bringing your squashes to harvest make sure to enjoy your just desserts!

Cured squashes have a very hard, dull skin protecting dense flesh of the most intense flavor. Store them on racks in a cool, dry place, but before you do that, for extra protection you can opt to give the skins a quick wipe over with a mild bleach solution – about one part household bleach to 10 parts water. This serves as a final barrier to rots and molds.

Squash will store anywhere from a month for spaghetti types, to six months for varieties of hubbard and buttercup squash.

I’m full of expectation for my pumpkins – I’m anticipating a satisfying soup and perhaps a decadent pumpkin pie. What squashes are you growing this summer, and where do you plan to store them? Let me know in the comments section below.

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Show Comments


"Hello Benedict, My guess is that you don't eat pumpkin skins but still, bleach? on your food? After all that effort to grow organic..."
Vera on Wednesday 2 September 2020
"Hi Vera. It really is a very dilute solution and you could use a vinegar solution instead if you wanted to avoid this altogether. The dilute bleach solution is just a belts-and-braces task, to help eke out a bit more storage life from the stored pumpkins. You could, of course, omit this step altogether."
Ben Vanheems on Friday 4 September 2020
" Hi BEn, The winter squash (Red Kuri)have failed this year! All the flowers mainly male, curled up and fell off after a few days. Is this the result of mildew? as the the leaves lookabit grey. Your views would be appreciated"
Glyn Davis on Monday 14 September 2020
"Hi Glyn. It is normal for the male flowers to fall off, as once they have flowered they won't turn into fruits, so they naturally just drop off. The female flowers should whither and fall off once the fruit has been set. If there were no fruits forming then this is a sign of either very poor pollination or poor growing conditions. The leaves definitely shouldn't have been grey, so would be an indicator of the latter, hence no fruits. "
Ben Vanheems on Thursday 17 September 2020
"Cheers Ben ,Thanks for your update"
Glyn Davis on Thursday 17 September 2020
"I know you can eat pumpkin leaves (I used to eat them as a child), but now I'm growing them I have no idea how or when to harvest them. Mine are crawling everywhere, putting down 'droppers', and are flowering/finished flowering, just beginning to produce the bulbs(?). (By the way, how do you stop them from taking over the entire garden?? Help!!!"
lara on Saturday 2 January 2021
"Yes, the younger leaves of pumpkins (but not the growing tips) can be picked off to eat. They need preparing to remove the spiny parts, and there are videos on YouTube etc that show you how to do this. The leaves are particularly popular in many African and Indian dishes, and great for soups, stews, curries etc. Search our other articles on growing pumpkins and squashes for more on how to control them. You can simply stop the vines sprawling any further and/or hem the growing stems in with sticks etc, to 'steer' them in the right direction. "
Ben Vanheems on Monday 4 January 2021
"Male flowers hold caterpillar inside the young male flowers. The caterpillars eat the pollen, I think as the pollen stick become brown. These male flowers also drop themselves. I don't see any butter flies around. How to overcome and which bug is doing this?"
Ganesan Adaikan on Tuesday 30 March 2021
"I'm not sure which bug that could be. You could try checking our squash pest guides to narrow it down. Head to the top of this page and click on the 'Pests' tab, then search for pests by Squash pests."
Ben Vanheems on Tuesday 6 April 2021
"Here in the US we fight with both squash vine borer and squash bugs. So far, I've kept up with removing them and their eggs. My delicata squash is doing so well! It's delicious roasted, I cannot wait for harvest time. Thanks for the great articles, Ben!"
Jamie on Wednesday 21 July 2021
"You're very welcome Jamie. I'm so pleased you are managing to stay one step ahead so far - keep it up!"
Ben Vanheems on Thursday 22 July 2021

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