Rising Acorn Squash: Tasty Winter Squash

Growing acorn squash is low maintenance and rewarding! Because of their large seed size, sowing acorn squash seeds is a great task for young children to get them involved in the garden. If you’d rather begin with pre-started plants then fear not! Squash seedlings are likely available at your local garden center. The growing process is long, but you’ll enjoy watching the acorn squash plant grow throughout the summer and into the fall. 

This plant originated in Central and North America and was introduced to early European settlers by Native Americans. It was a staple crop and often a part of a three-sisters garden which includes corn, pole beans, and squash all being interplanted for the benefits that they provide each other. 

Acorn squash is very easy to prepare and cook which makes it a great addition to every edible vegetable garden. The flavor has been described as mild and slightly nutty. It requires no peeling, just slice in half and roast cut side down in the oven until tender. Top it with some butter, and a sprinkle of salt, and eat the flesh right out of the rind. Acorn squash is also an excellent stuffable squash since they have a shape that is nearly perfect for stuffing. Half a squash makes for a perfect serving size. (Also, they taste incredible when stuffed with mushrooms and wild rice!)

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Quick Care Guide

Growing acorn squash is a great way to get storable veggies. Source: Gary J Wood

All About Acorn Squash

A growing acorn squash plant loves full sun conditions. Source: jfeuchter

Cucurbita pepo var. turbinata is also known as Des Moines squash and pepper squash. They are a type of winter squash, but are more perishable and have a shorted shelf life than others of their kind. They can also be eaten somewhat immature whereas other winter squash should fully mature before being harvested. C. pepo includes plants such as butternut, spaghetti squash, and pumpkins. Summer squash such as zucchini is a subspecies of Cucurbita pepo. It is said that the name Des Moines squash comes from a popular variety, Table Queen, that was first sold by an Iowa seed company and gained popularity in the 1800s. 

There is some mystery around the Des Moines cultivars and there are claims of it being cultivated in Denmark, however, these claims have been unsubstantiated and it’s more likely that it was cultivated alongside other squashes in North America. 

These plants have large fan-like leaves and thin stems that will either lead to a central growing point (for bush types) or to a vine (for vine types). The flowers are large and yellow and resemble zucchini blossoms. They are also edible and taste amazing when battered and deep-fried. The shape of the squash resembles an acorn with ribs and a dark green rind sometimes with a tinge of orange. 

People grow acorn squash and plant acorn squash seeds because they’re high in Vitamin C. 

Planting Acorn Squash

The best time of year to plant acorn squash seeds is after all danger of frost for the season has passed. Pick a spot in your garden that gets plenty of sunlight and has plenty of space for the plants to bush out, sprawl, or grow up a raised bed trellis depending on the variety that you choose. Keep in mind that the decision to sow directly from seed or transplant out seedlings will depend on the length of your growing season. If sowing acorn squash seeds directly, start planting after the soil temperature is consistently at least 60 degrees. When transplanting seedlings, wait until 1-2 weeks after the average last frost date when nighttime temperatures are in the 50s. Make sure to space plants accordingly. Place one transplant per 2 square feet. Thin direct sowed plants in the seedling stage to this same spacing.

Acorn Squash Care

Squash blossoms are both beautiful and productive. Source: pinkishkaty

Now we’ll discuss the care of the beloved winter squash. Hopefully, this encourages you to add it to your vegetable garden as soon as possible! Following these gardening tips will ensure a bountiful harvest. 

Sun and Temperature

Acorn squash love full sun! They will require at least 6-8 hours of direct sunlight per day. They can tolerate partial shade when grown in a three-sisters situation, but it’s best to grow them around the perimeter so that they are still getting adequate sunlight. Although they love sunlight, they don’t do well in excessive heat. In extreme heat (temperatures above 90 degrees Fahrenheit) when the sun is beating down on them with scorching intensity, the flowers may drop and fruit may fail to form. Acorn squash plants can be grown in zones 3-10, but prefer warmer climates and do best in hardiness zones 5-9 where it isn’t too cold and also isn’t too hot. 

Like most plants in the Cucurbita family, they cannot handle even a light frost (which occurs at 32 degrees Fahrenheit). Acorn squash seedlings will need to be transplanted out 1-2 weeks after the last frost when soil temperatures are consistently at least 60 degrees Fahrenheit. It’s very difficult to protect this plant even with row covers during cold periods so your best bet is to wait until the last spring frost has passed. If you live in an area with a long enough growing season then you’ll be able to sow your seeds directly. Areas with short growing seasons should start plants indoors to give them a head start and then transplant them out. To calculate the length of your growing season determine the number of days between your last frost in spring and your first fall frost date. 

Water and Humidity

Since acorn squash plants are particularly susceptible to powdery mildew and downy mildew, it is a best practice to water them early in the day and water at the base of the plant to prevent wetting the foliage. As a general rule squash plants require moist, well-draining soil. Water your plants deeply once per week. It is easiest to place young plants along drip irrigation lines to ensure that they receive this deep watering without wetting their leaves. Acorn squash leaves may wilt slightly in the heat of the day, but fear not, this is not a sign of underwatering. They will perk back up once the sun begins to set and the heat of the day has passed. If you witness wilted leaves early in the morning before it is hot outside, then you may consider increased watering. The general guidance when you grow acorn squash is to keep the soil moist, but not soggy. 

Soil

Acorn squash prefers well-drained soil that is rich in organic matter. A layer of compost at the beginning of the growing season will help accomplish this. These plants can create a complex root system that can inhabit the top 8-12 inches of soil. Working compost into this top layer of soil will get your plants off to a great start. You can grow acorn squash in a 5-gallon bucket as long as the same soil requirements are met, although it’s worth noting that their root system generally spread wider rather than deep so container growing is not the best option. Give this plant about 2 square feet between it and other plants.

Fertilizing

When you grow acorn squash, its complex root system and large size makes them natural heavy feeders. For this reason, they can benefit greatly from a good all-purpose fertilizer. They can be fertilized every 3 weeks during the growing season. Once the plant begins to set fruit then you can switch to a fertilizer low in nitrogen and high in potassium and phosphorus for good fruit development. A liquid fertilizer watered around the drip line of the plant is optimal. 

Pruning & Training

Pruning for acorn squash is not necessary other than removing dead or yellowing leaves. Cut them back at the base of the stem to prevent them from taking away valuable water and nutrients from the healthier parts of the plant. When pruning away damaged or diseased leaves, be mindful not to cut through the main stem of the plant. Otherwise, this plant can take pruning at many locations without inhibiting its growth. 

There are two main varieties of acorn squash: bush varieties and vining varieties. The bush variety will remain stout and, well, bushy. They resemble zucchini in terms of growth habits. The vining varieties more closely resemble butternut and can be trained to climb up a trellis. This may be useful if you’re limited on garden space. This will allow you to grow acorn squash vertically and make the most of all the square footage available in your vegetable garden. 

I’ve had the most success with growing winter squash on a cattle panel trellis. Cattle panels can be purchased at your local feed store or ordered online. They generally come in 8ft or 16ft lengths and can be bent to create an arched trellis, or cut with bolt cutters to create a flat vertical panel. Plant your acorn squash seeds or starts at the base of the trellis and once it is tall enough to do so, weave it through the first few spaces on the cattle panel. The squash plant will take it from there! They will sense the panel and put out tendrils to latch onto it and begin to climb on their own. 

If you’re growing vertically then you may need to support the weight of the fruit once it begins to mature to prevent it from bringing down the entire vine. You can support them by creating a cradle out of old pantyhose or an old t-shirt. These vines can generally withstand the weight of the fruit without much support, but it may put your mind at ease to support it. 

With the bush variety, you may consider adding a barrier between the squash and the soil as it begins to mature. Without a barrier, like a piece of slate, the squash may rot on the side that rests on the ground. This is an issue in areas that are especially moist and wet while the fruit is maturing, otherwise, this shouldn’t be an issue. Follow these growing tips and you’re sure to have a successful squash season.

Propagation

Acorn squash can only be grown from seeds and cannot be propagated from cuttings or other methods. To give your acorn squash seeds the best start plant five or six seeds in a mound about an inch deep and loosely cover with soil. Once they emerge, thin weaker seedlings when they’re about 3-4 inches tall and have their first true leaves. You can save seeds from season to season, however, members of the Cucurbita family very easily cross-pollinate so if you’ve planted other members of this family nearby then any seeds that you save may turn out to be a franken-squash rather than true to type. 

Harvesting and Storing

This halved acorn squash reveals its seed chamber. Source: Smitten with Kittens

Now that we’ve grown our squash, let’s make sure that we’re ready to harvest and store it properly. Here are more gardening tips for growing this lovely plant.

Harvesting

As mentioned above, the blossoms can also be harvested and eaten. If you choose to do this, make sure to harvest only the male blossoms as you’ll want to leave as many female blossoms as possible to turn them into mature fruit. 

It’s important to harvest acorn squash before the first hard frost. Although they are referred to as winter squash they do not do well in cold temperatures. They are called so because, unlike summer squash, they will form a thick skin that allows them to more easily be stored over winter rather than eaten fresh in the summer. Other squashes like this include spaghetti, butternut squash, and pumpkins. 

You’ll know that they’re ready to harvest when the ribs are dark green, the skin is firm to the touch and the stem begins to turn brown. They continue to ripen slightly after they are harvested and there is no danger in eating an immature fruit. The deep green color of the skin, the browning on the stem, and the dying back of the vine/bush are all great indicators. 

Once you’re ready to harvest grab a pair of sturdy pruners. It is not recommended to try and pull this fruit from the vine with your hands as you may damage the vine and jeopardize the remaining fruits. Cut the stem about 2-3 inches above the fruit. Leaving some of the stem intact will help lengthen the time that you’re about to store it long term. After harvesting, if there is no acorn squash further down the vine then you will be able to prune back this section so that the plant can focus on ripening any remaining fruit.  

Storing

To store acorn squash for the long term first you’ll need to sort through them. Any squash without their stem, with any soft spots or any type of damage to the outer rind, should be eaten immediately as they will not store well. Leaving the stem attached is an important step as the lack of an intact stem will allow moisture to get inside and rot your acorn squash. They can go through a process of curing outside, in a cool dry place, around 55 degrees Fahrenheit such as a root cellar, garage, or basement. Leave them for a few days until the stem has hardened completely. 

Acorn squash is one of the most perishable winter squashes. If you’d like to take an extra step to ensure a longer shelf life then you can wipe them down with a solution that is 1 part household bleach to 10 parts water which will discourage rot and mold growth. Generally, they can keep for 3-4 weeks but can last even longer in ideal conditions. 

Troubleshooting

As squash get towards over-ripe, they start to turn yellow but are still edible. Source: Franco Folini

Although this is a relatively low-maintenance and straightforward plant to grow, there are a few pest issues to address. Read on to find out how to stay ahead of them! 

Growing Problems

As mentioned above, acorn squash plants do not appreciate extreme heat. and prolonged temperatures above 90 degrees Fahrenheit can cause the flower to drop, and then the fruit fails to form. In times of intense heat, you can provide your plants with shade cloth to help ease the stress put on them. Watering your plants in the morning will also help keep them cool throughout the day.

Like most members of the squash family, acorn squash plants have both male and female flowers. The male flower has a long thin stem and the female flower has a tiny acorn squash shape at the bottom that will turn into a viable acorn squash once it is successfully pollinated. If you notice that the tiny acorn squash is shriveling up then you likely have a pollination issue. If the female flowers fail to get pollinated then they will shrivel up and die rather than producing fruit. Attracting pollinators to your garden with companion plants such as dill, chamomile, nasturtium, and other flowering herbs is beneficial. When all else fails you can easily hand pollinate to ensure fruit production by taking a q-tip and brushing it on the inside of a male flower and then moving it to the inside of a female. 

Pests

Unfortunately, like many members of the Cucurbita family, acorn squash also has many common pests that are specialized in destroying this plant. Among these insect pests, cucumber beetles, squash vine borers (SVB), and squash bugs are the most common. SVB, as their name suggests, bore into the vines where they lay their larvae. This prevents the plant from taking up water and it will eventually wilt and die. These pests are found in the eastern United States. Once they have bored into the vine it’s possible to bury another section of the vine in the dirt to get it to root, but this has varying degrees of success depending on the damage that has already been done. Bt spray can be used to destroy vine borers and can even be injected into the stem to kill their larvae. 

Crop rotation can be a good preventative measure because it prevents overwintering pests from emerging alongside your newly planted seedlings. Clearing away plants at the end of the season will help prevent them from overwintering in the first place. Once your plant is done for the season, cut at the base of the plant as close to the soil level as possible. The roots can be left in place to add organic matter to your soil while the rest of the plant material should be discarded. It is not recommended to compost plants if you suspect a potential pest issue. 

With most of these pests, the best defense is a good offense. Be vigilant and inspect your plants often. Squash beetle eggs are particularly easy to spot. They lay their eggs on the undersides of the leaves and they appear small oblong and bronze. It’s easy enough to squish them between your fingers. Adult bugs can be picked from the plant and dropped into a bucket of soapy water to kill them. They also make an excellent snack for your chickens. 

Diseases

Overwatering can cause the perfect conditions for fungus to take hold, especially in hot and humid climates. If too much moisture splashes onto the foliage during watering then this can contribute to issues with downy mildew. 

Downy mildew is often mistaken for powdery mildew but it appears as yellow leaf spots on the tops of the leaves with black spore masses on the underside of the leaves. In contrast, powdery mildew appears as more of a white flour-like powder on the leaves. 

To prevent these issues, always bottom water your plants, neem oil may also be sprayed as a preventative measure to reduce the colonization of spores on foliage. In advanced cases of this mildew, it may be best to remove and destroy infected plant material to prevent it from spreading to nearby healthy plants. After removing infected material, spray neem oil or a liquid copper fungicide onto the remainder of the plant and nearby plants to reduce the risk of further spread. 

Frequently Asked Questions

Ripe acorn squash have deep green flesh and the vines may be yellowed at harvest time. Source: apple_pathways

Q: How long does it take for acorn squash to grow?

A: 80-100 days from seed, 50-70 days from fruit set. 

Q: How many acorn squashes will one plant produce?

A: It depends on the variety but they can produce anywhere from 5-25 lbs of squash.

Q: Do I need a trellis for acorn squash?

A: You don’t need one per se, but it’s a great way to make the best use of your gardening space. 

Q: Is acorn squash hard to grow?

A: This is a great beginner plant that can become prolific under the right conditions. 

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