Summer squash is fairly easy to grow and produces quite an abundant harvest. There are many varieties to explore beyond zucchini. Some of my favorite varieties include Dark Star, Staightneck, Cocozelle, and Costata. The days to maturity for most varieties is 40-55 days so depending on your climate, you may be able to have two rounds of harvest. Because they produce so much in such a short time, they are a great candidate for secession planting! 

Sowing Seeds

Seeds can be started indoors or direct planted outdoors. If starting seeds indoors, start them 3-4 weeks before your last frost date. Sow the seeds 1 inch deep with the more narrow end pointed upward. Keep the soil moist and cover it with a dome.

They need some heat to germinate so place them on a heat mat or in a warm area of your home. After germination, place them under a grow light, keeping the light as close to the plants as possible without touching them.

Planting

If direct sowing outdoors, wait until the danger of the last frost has passed as they are not cold tolerant, I typically wait 1-2 weeks.

Summer squash plants get fairly large so space the plants 2-3 feet apart in rows 3-4 feet apart. They like full sun so ideally plant in a location that receives 6-8 hours of sunlight. They also prefer well-draining soil so consider amending with compost or organic material to improve drainage. 

Consider growing vertically to maximize your garden space! Before planting the squash, insert a sturdy stake to tie the squash to. As the plant grows, carefully secure the main stem to the stake with ties. Cut off the lower leaves as the plant grows taller.

Care

Squash are heavy feeders, meaning they take a lot of nutrients from the soil. Feed them with an organic fertilizer every 3-4 weeks during the growing season. A simple 10-10-10 fertilizer works great assuming your soil is healthy. It is important to water at the root of the plant and not overhead. Overhead watering can lead to fungal diseases. 

Pollination is necessary for your plant to produce squash. Naturally, squash flowers are pollinated by pollinators, yet sometimes this doesn’t take place and you will be left with no fruit! There are a couple of things you can do to ensure pollination. First, plant flowers or flowering herbs nearby to attract pollinators. Second, you can hand pollinate. It’s pretty simple, you will take the pollen from the male flower and swipe it around the inside of the female flower. I suggest doing this early in the morning.

Pests and Disease

Squash Vine Borer is the most common pest problem and can be quite difficult to control. I suggest keeping the plant trimmed off any dead leaves and the soil area clear of debris so you can have a better view of any possible first signs. There are some organic pest controls on the market that claim to help prevent them but covering the area in insect netting has worked best for me. SVB also have a “season” so if you plant squash at the same time every year and they kill your plant every year, consider moving your planting date back a couple of weeks and you may miss their life cycle. 

Powdery mildew can easily affect squash plants but it won’t necessarily kill them. It will appear like a white powdery substance on the leaves of the plant. Keeping good air circulation by staking or trellising as well as cutting back dead leaves will help prevent. If your plant is showing signs of powdery mildew, I suggest spraying with an organic fungicide. I have used Captain Jack’s Copper Fungicide in the past and it has worked great.

Harvest

Most plants will be ready to harvest in 50-60 days yet the harvest can last weeks! Ideally, you’ll want to harvest when the fruits are still somewhat small and tender as they can get woody exteriors and seedy interiors. The fruits are still edible at any stage of growth, however. Cut the squash from the vine leaving about an inch still attached.

Storage and Preservation

Most summer squash will last 1-2 weeks in the refrigerator if kept whole. They can be stored at room temperature but the shelf life is only about 3-4 days.

Preservation Methods

• Canning (pickles and relish)
• Freeze
• Dehydrating
• Fermenting