To grow winter squash successfully, from sowing the seed to storing it for future use, requires patience, care, and a little bit of know-how. With the right variety, growing conditions, and harvesting techniques, you can enjoy the sweet and savory flavors of winter squash throughout the year. Let’s go over the steps to growing winter squash from sowing seed all the way to storage, including some tips and tricks along the way.

Choosing the right varieties

Winter squash come in a wide range of options in terms of shapes, sizes, and colors. From the traditional orange pumpkins to spaghetti and butternut squashes, the choices are endless. To pick the right variety of squash, it is crucial to go through the descriptions provided on the seed packets or catalogs. This helps in selecting the squash that caters to your desired flavor or intended use. Although most winter squash varieties possess some degree of sweetness, there are some that are sweeter than others. Furthermore, certain types of squash are perfect for roasting or using in pies. If storing squash for winter consumption is your goal, consider varieties with longer storage life.

Some of my personal favorites include:

• Sugar Pie Pumpkin
• Winter Sweet
• Honeynut Butternut
• Sweet Meat
• Fairytale Pumpkin
• Waltham Butternut

Sowing Seeds

Winter squash is typically sown directly into the ground once the soil has warmed up in the spring. However, you can start them indoors if you have a shorter growing season like I do to give them a jump start.

If planting directly outdoors, choose a sunny and well-drained spot in your garden. Enhance the soil by adding compost or organic fertilizer. Sow the seeds 1 inch deep with the pointed end up. Space seeds 4-5 feet apart, with rows spaced at least 6 feet apart. Water the seeds regularly, keeping the soil moist but not waterlogged.

If starting seeds indoors, sow your seeds 3-4 weeks before your last expected frost date. Don’t forget to harden them off before transplanting them into the garden. Once your last frost date has passed and the plant has grown at least one set of true leaves. Follow the same spacing guidelines as direct sown seeds above. Dig a hole slightly larger than the root ball, sprinkle a small handful of slow-release fertilizer or compost in the hole, plant, and water them in. 

Care

Water the plants deeply once a week at the base of the plant. Fertilize with an organic,  balanced fertilizer every 3-4 weeks. I suggest using a phosphorus-rich fertilizer as the plant begins to produce squash.

Winter squash is a sprawling plant that can take up a significant amount of garden space. To maximize your garden space and prevent some diseases, you can provide vertical support. The plant will be heavy as the squash begins to grow so make sure it is something sturdy like a cattle panel. Alternatively, you could allow the plants to vine along the ground if space permits.

While squash plants are typically pollinated naturally by bees or other pollinators, there may be instances where this does not occur. To encourage pollination, I recommend planting flowering herbs or flowers nearby to attract pollinators. In the event that your squash plant is producing flowers without forming squash, it is possible that the flowers were not properly pollinated. You can assist the pollination process by hand pollinating the flowers.

Hand Pollinating Squash

1. Identify Male and Female Flowers: Winter squash plants produce separate male and female flowers. The male flowers have a long stem and the female flowers have a small fruit or bulge at the base of the flower.
2. Choose the Right Time: Male flowers usually appear first, followed by female flowers. Wait until you see a few female flowers open before attempting to hand-pollinate. I also suggest performing this during the morning hours when the flowers are fully open.
3. Collect Pollen: Gently remove the petals from a male flower to expose the stamen, which contains the pollen. Use a cotton swab to collect some pollen from the stamen. You could also snip the stamen right off and use that to pollinate the females. 
4. Pollinate the Female Flowers: Gently brush the collected pollen onto the stigma of the female flowers. The stigma is the sticky, protruding part in the center of the flower.
5. Repeat the Process: Repeat the process for each female flower that you want to pollinate, using a clean brush or cotton swab for each flower.

Pests and Diseases

Similar to summer squash, winter squash is most prone to squash vine borers and powdery mildew.

The larvae of squash vine borer enter the stems, causing damage and often killing the plant. Signs of vine borer infestation include wilted leaves and sawdust-like debris around the base of the plant. Use beneficial nematodes or insecticides, such as neem oil, to control vine borer larvae.

Powdery mildew is a fungal disease that can cause a white, powdery coating on the leaves and stems of squash plants, leading to reduced photosynthesis and stunted growth. To prevent powdery mildew, provide adequate spacing between plants to promote air circulation and reduce humidity. To control powdery mildew, remove affected leaves at the first sign and use organic fungicides such as copper sprays or sulfur.

Harvest

Most winter squash varieties take 80-100 days to mature, depending on the variety and growing conditions. The squash is ready to harvest when it sounds hollow and the skin has hardened to the point where it can’t be easily punctured with a fingernail. Use a sharp knife to cut the squash from the vine, leaving a few inches of stem intact.

Curing

Begin by wiping with a damp cloth to remove dirt or debris and dry thoroughly. The ideal temperature for curing winter squash is around 80°F with a relative humidity of 60-75%. However, it is not always possible to maintain these exact conditions, especially in home environments. In general, it’s best to aim for a warm and dry area with good ventilation, such as a covered porch or a well-ventilated garage, and try to keep the temperature above 70°F. Turn the squash over every few days to ensure even drying.

On average, it will take 10-14 days to cure your winter squash. You will know that your squash has fully cured when the following conditions have been met:

• The skin has hardened further
• Stems are fully dried through
• Uniform color with no green spots
• Tapping on the skin sounds hollow, indicating that the flesh has shrunk away from the rind.

Storage and Preservation

Store cured squash in a cool and dry place, such as a root cellar or pantry. The ideal storage temperature is around 50-60°F. If you do not have a root cellar, locate the coolest place in your home such as a basement or poorly insulated room. Winter squash can last store for 3-6 months or longer if cured and stored properly. Good options for long-term storage include acorn squash, butternut squash, and spaghetti squash.

Preservation Methods

• Root Cellar
• Pressure canning
• Freezing
• Dehydrating