Happy summertime. I hope you’re all enjoying waterfalls and (soon) watermelons. This month’s column features tips for growing squash, as well as ways to reduce voles from devouring your harvest.
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What’s the best way to grow summer and winter squash?
Growing summer and winter squash (which include zucchini and pumpkins) can be tricky. Fortunately, they’re worth a little extra effort because they’re so delicious and prolific.
First, the basics: All squash are heat-loving plants and intolerant of cold weather. They can be started indoors in a heated space and then transplanted after the danger of frost has passed, or they can be directly sown in the garden once it’s reliably warm. I tend to start a few zucchinis and summer squashes inside for transplant, then do a second succession directly in the ground. For winter squash, I always direct sow. I’ve noticed that the plants grow much larger and are more robust when planted this way. Despite the name, winter squash ripen in the fall and are harvested before the frost. They keep through the winter, which is when most people eat them, hence the name.
Squash are heavy feeders, meaning they thrive in soil with high fertility. If you don’t have rich soil, you can add an organic fertility source before planting squash and/or apply a liquid fertilizer throughout the growing season. Be careful with adding too much nitrogen, which can lead to a proliferation of male flowers but fewer of the female flowers that are needed for the fruits you want to harvest. Compost or composted manure are great choices, along with a balanced organic fertilizer such as Plant-Tone, which contains nitrogen along with other macro- and micronutrients.
As with all garden veggies, be sure not to plant squash in the same spot year after year. Not only does this deplete soil of the nutrients those plants need, but it also increases the chances of pest issues. Because many pests overwinter in the soil, they’ll be only too delighted to encounter their favorite food source again and again.
Finally, squash flowers are pollinated by insects, especially both native and domesticated bees. Keep an eye out for buzzing helpers carrying pollen from male to female flowers on your squash plants, as this is necessary for them to grow fruits.
How do I minimize squash bugs and mildew interruptions?
I’ll tackle powdery mildew first, then get into pest issues. This is a fungal pathogen that infects the leaves of plants, and squash plants are particularly susceptible. Moist and cool conditions are ideal for powdery mildew. Sometimes, these conditions are unavoidable, such as on overcast days after thunderstorms. Other times, we unknowingly welcome powdery mildew by watering late in the day, watering on top of plant leaves and/or planting squash in semishade conditions.
To minimize powdery mildew, be sure to plant squash in full sun. If you’ll be overhead watering (with a water wand, watering can or sprinkler), do this early in the day so that the sun can quickly evaporate any moisture from the surface of the leaves. If possible, don’t let water touch the surface of the leaves; you can do this by carefully aiming your water wand or watering can right at the base of the plant, or by using a drip irrigation system.
If, despite your best efforts, you end up with powdery mildew, don’t despair! Plants can outgrow this issue if they have enough fertility, moisture and sun. A mild case of powdery mildew won’t actually decrease yields significantly. As soon as you see signs of powdery mildew, clip off and discard the infected leaves.
One simple, effective preventative treatment for powdery mildew is diluted milk spray. A mix of 30% milk and 70% water can be sprayed on in the middle of the day (in direct sun) every 10 days or so and has been shown to be as effective as chemical pesticides.
Now, on to a little botany lesson. All summer and winter squash are in the genus Cucurbita, and there are three main species that we cultivate: pepo, maxima and moschata. Two other species are cultivated elsewhere in the world, but for your Western North Carolina garden, it’s likely that you’ll be dealing with one of these three. All types of squash have their ancestry in Mesoamerica and South America, where they’ve been cultivated for thousands of years.
Most summer squash varieties are in the pepo species, with the notable exception of a delicious viney type called tromboncino, which is in the moschata species. Winter squashes and pumpkins, on the other hand, are mostly in the maxima and moschata species, with the notable exceptions of delicata and acorn squashes. Maximas include blue hubbards, buttercups and kombuchas. Moschatas include butternuts and cheeses. If you’re not sure what species you’re working with, a quick internet search can answer the question.
Why all this scientific mumbo-jumbo? Well, it turns out that plants in the moschata species tend to be resistant to squash vine borers, as well as several other pests. If you’re really struggling with vine borers, choosing moschata varieties can be a saving grace. Even though I love the flavor of maximas like buttercups, I always plant a larger section in moschatas because they are much more reliable.
Other pests that dine on squash plants include squash lady beetles, which look like orange, oversized ladybugs; “squash bugs,” which look like stink bugs; and both striped and spotted cucumber beetles, which are pale green with black stripes or spots.
Along with generally providing ideal conditions that lead to strong, vigorous plants, the best way to deal with these pests is, unfortunately, hand picking. Midday is the best time to spot these pests, as they’ll be most active. Carry a container of soapy water with you and pop the bugs into it, where they will perish. Be sure to look on both the tops and undersides of leaves for mature insects and eggs. Use your fingers to squash the eggs with a rubbing motion.
We’ve got voles in our garden. What do you suggest?
Oh, the varmints! They do keep us on our toes. I, too, deal with voles in my garden. And while I haven’t found any foolproof method to completely eliminate them, I do have some tips for curbing their populations (and the damage they do).
First, traps are much more effective when they’re partially buried. Voles don’t like being seen, so making the traps seem like welcoming, dark little caves can go a long way. Another way to take advantage of voles’ shyness is to minimize overgrowth and ground cover in your yard or garden. Keep the lawn mowed short and maintain an exposed border around garden beds (with tightly packed mulch instead of any bushy growth of weeds or crops). If you have brush piles, make sure they’re far away from your growing spaces.
Voles dislike both spicy chilis and coffee, so sprinkling these household items around your yard or garden can help deter the pests. You can mix a few spicy chilis with a teaspoon of biodegradable soap and a quart of water in a blender. Strain this liquid and spray it around the bases of plants.
Alternately, you can sprinkle some cayenne powder down in the holes where you transplant crops so that the voles encounter that spicy flavor before tasting your plants’ sweet roots. Coffee grounds can be sprinkled around plants to help protect them or mixed into a planting hole. Don’t overdo the grounds, though, as too many can tie up nitrogen and inhibit plant growth. About a tablespoon or two per plant is plenty.
I can’t think of voles without fondly remembering our old cat, Tigger, RIP. For about four years we were blessed with his hunting prowess and voracious appetite, which kept our vole population down. There’s no way to know if a cat will be an effective vole killer, but it’s worth having one around to give them a chance.
Other vole predators include owls, hawks and coyotes. You can encourage birds of prey to help you out by creating habitat for them. Perches and boxes are easy to build and invite natural predators to take care of the voles for you, all while filling their own bellies. What a beautiful balance!