How to Avoid Common Squash Problems

28 August 2020, written by Benedict Vanheems

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 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.

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.

“Supporting — 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.

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.

“Curing — 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.

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.