Out of all of the winter squash varieties, the acorn squash (Cucurbita pepo var. turbinata) is one of the most recognizable. It’s also one of the easiest to harvest and store. But there are still a few things every gardener should know before growing this hearty vegetable.
In this article, I’ll explain the ins and outs of harvesting acorn squash, including when to pick acorn squash for the best flavour and shelf life. I’ll also offer some expert troubleshooting tips that will help you get the most from the acorn squash in your garden each year.
Acorn Squash Outdoor Vs Greenhouse
Acorn squash can be grown any time there is no frost. Traditional garden-grown squash is beholden to the length of your region’s summer and must be planted early enough in the season for the fruit to fully mature before early winter frosts.
In some cooler climates, there may be just enough time between frost dates to grow acorn squash (which requires up to 100 days to bear ripe fruit). Planting acorn squash in a heated greenhouse can extend the growing season by several weeks in either direction.
Another benefit of planting acorn squash in a greenhouse is that you don’t need to rush to harvest the fruit in the fall. You can allow the squash to fully ripen on the vine without fear of early frost damage.
When Is Acorn Squash In Season
The acorn squash growing season starts after the final frost date in the spring and ends with the first frost date in the fall of the same year. In most cases, it’s best to wait well past any risk of frost before planting tender young plants outdoors. Either start them off undercover, or plant seeds directly in the ground when soil temperatures reach 70 degrees Fahrenheit.
The winter squash, just like pumpkin grows at an astonishing rate in the right conditions. Plant them outside too early and you may subject them to cold shock or worse still kill them off with the slightest frost.
In most regions, the peak harvest time for acorn squash is mid-fall to early winter. In warmer climates or greenhouse environments, though, fresh acorn squash may be available year-round.
How Long Do Acorn Squash Take To Grow
Squash produces mature fruits 80 to 100 days after germination. This equates to about 50 to 60 days between the initial fruit setting and full ripening.
Factors that affect fruit development include chosen cultivars, average daily temperatures, irrigation, and overall plant health. Acorn squash grown in subpar conditions will take longer to produce mature ripe fruit.
How To Tell If Acorn Squash Are Ready To Pick
Harvesting winter squash too early or too late can result in an entire season’s work going to waste. So before removing any fruit from your plants, you must first know how to tell whether an acorn squash is truly ripe or not.
Colour is one of the best ways to tell if an acorn squash is ready to be cut from the plant. A typical acorn squash is dark green with a yellow patch on its underside. When the acorn squash is ripe, this spot turns a deep orange colour. An acorn squash that has turned predominantly orange has been left on the vine too long and is now — unfortunately — overripe.
Tough Skin is another tell-tale sign that your acorn squash has reached maturity in its texture. Ripe squash has a tough, almost impenetrable rind. If you press your fingernail into the fruit’s skin and it easily pierces, the squash is not yet ripe.
Woody Stems are also a sign to indicate the squash’s ripeness. The segment of stem attached to winter squash tends to turn woody or “corky” when the fruit is mature. A soft, green stem is a clear indicator that the squash needs more time to ripen on the vine.
Size is rarely a good indicator that acorn squash is ready for harvest. This winter squash tends to reach its full size early on in the season, so don’t be alarmed if the fruit appears to stop growing long before the expected harvesting time. The squash will continue to mature even while its size remains largely the same.
How To Harvest Acorn Squash
Winter squash should always be cut from the vine rather than pulled or twisted. Use a clean, sharp blade to remove ripe fruit from the plant. Leave at least an inch of stem attached to each squash may prevent stem-end rot. Be careful not to cut or bruise unripe fruit still on the plant during the harvesting process.
After harvesting, inspect each squash for signs of damage. Set aside any fruit with bruising or damaged skin to be consumed as soon as possible.
Many types of winter squash develop a better flavour when left to sit somewhere warm for several days — a process called curing. According to Iowa State University, however, this is not true of acorn squash. Instead, curing will actually decrease the quality and shelf life of acorn squash.
Any acorn squash that you will not use immediately should be stored in a dry, well-ventilated location that stays between 50 and 55°F. Place the squash in a single layer away from fruit like apples and pears, which release ethylene gas. Acorn squash should keep for up to 2 to 3 months in these conditions.
Will Acorn Squash Ripen Off The Vine
Acorn squash, just like pumpkin, melon and cantaloupe, should be left to ripen on the plant under the sun. Any fruit harvested before they are ripe will have a lacklustre flavour and likely won’t keep for long in storage.
It’s generally safe to leave acorn squash on the vine for a few weeks after it fully ripens. In other words, it’s better to err on the side of harvesting too late rather than too early. However, leaving your squash in the garden for longer than necessary also increases the risk of weather or animal damage.
Some beginner gardeners mistakenly think that leaving a few inches of stem attached to harvested acorn squash will allow them to continue ripening. While it’s true that you should leave at least an inch of stem attached to each squash to improve fruit quality and storage, this will not extend ripening past harvest.
There may be times when frost is on the forecast yet your squash plants still have unripe fruit left on the vine. I recommend covering the plants if possible rather than harvesting the fruit prematurely. Placing an insulating tarp over in-ground squash plants will typically offer adequate protection from early frost and allow the fruit to fully ripen.
Do Squash Plants Keep Fruiting
Acorn squash is an annual vegetable with a relatively long growing season. Because of this, you shouldn’t expect to get more than one harvest out of a single plant. By the time you harvest the first squash of the season, all other fruit on the same plant should be nearly ripe as well.
Once your acorn squash plants stop producing, you can remove them from the garden. I prefer to discard yard and garden waste into a general compost pile that can be reused in future years. However, any plant matter that shows signs of disease should be discarded separately — e.g., via burning or your household garbage bin.
FAQ’s Acorn Squash Harvest
Iowa State University – Harvesting and Storing Winter Squash
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.