Squash is not just delicious, but is a healthy and versatile addition to your backyard garden, as well. Squash is high in vitamins A and C, and an excellent source of all natural fiber, potassium, folate, and iron.
The squash we are familiar with today evolved from wild squash which originated in the region between Guatemala and Mexico. Wild squash has grown for over 10,000 years in North America, and the first squash plants were harvested primarily for their seeds, as they contained only small amounts of bitter flesh.
Squash was grown natively by the Wampanoag and was considered one of their three staple crops, along with maize and beans. Over time, as squash cultivation moved across America, Portuguese and Spanish conquerors would introduce the squash crop to Europe. Eventually, making its way around the world.
Moreover, the Iroquois referred to these plants as the “Three Sisters” for their ability to work symbiotically to correct soil, provide protection for crop growth, and proper nutrition in the body. Additionally, the word “squash” comes from the Narragansett (Algonquin) language, further solidifying this crop’s roots in Native American history.
Start Growing Squash
Typically, squash is divided into two types:
- Summer squash, which has thin, edible skins and is harvested while slightly immature.
- Winter squash which has thick skins are harvested after maturation. Additionally, they can be stored for consumption through the winter months.
First, determine which type (or types!) of squash you prefer to grow based on your taste and harvest or storage preferences. Remember that summer squash tends to have a much shorter shelf life than winter squash. Also, that winter squash is known to make excellent sweet or savory side dishes and desserts in the cooler months when stored.
When and Where Should You Grow Squash
Summer squash prefers warm weather, preferably in the range of 65 to 85 degrees Fahrenheit. You can start seeds indoors four weeks before the last expected frost date. Then, move them outdoors after all signs of frost disappear. Due to these plants not thriving in cool conditions, ensure they have plenty of warmth. To do so, cover their bed with lots of organic matter in the form of compost and mulch. This will provide heat and nutrients for your growing plants.
Summer squash requires a minimum of six hours of sunlight daily. Although, too much direct heat in the afternoon may cause the plants to droop. While you can harvest summer squash all summer long, you’ll want to stop planting seedlings 12 weeks before your average first fall frost date.
Winter squash follows the same general rules for planting as summer squash does. However, there is a few minor changes or caveats. To start, winter squash thrives in soil that is between 70 and 95 degrees Fahrenheit. The warmer the temperatures the better. Also, winter squash is often grown on trellises. Specifically, if they are a vining variety, which maximizes smaller garden spaces and can allow for more thorough visual inspection of some species’ quite sizable fruit.
Both summer and winter squash prefer fertile, well-drained soil with a pH between 6.0 and 6.5. It is recommended to either grow your squash in an area of your garden that was previously used for a compost pile or to thoroughly incorporate two heaping shovels of compost into the site where you choose to plant. Moreover, squash prefers loose soil. For this reason, be sure to mix the compost at least twelve inches into the ground when preparing your soil. This will ensure you thoroughly incorporate the compost and break up the soil as you go.
Growing Squash From Seeds
Squash plants are often started indoors in medium-sized peat pots, roughly three weeks before the last expected frost.
- First, fill each pot halfway with your favorite seed-starting soil mix.
- Place two seeds one inch deep into the center of the peat pot.
- Water thoroughly.
- Keep the pots between 65 and 85 degrees (Fahrenheit) to encourage germination. Grow lights are an excellent way to ensure a constant temperature is maintained.
The seeds should sprout rather quickly. Once they are approximately two inches tall you will need to thin them out to one plant per pot. You can do this by untangling the roots with your fingers or by using scissors to separate.
With each seedling now in its own pot, you’ll want to begin the process of hardening them off before moving them completely outdoors. The hardening off process helps the tender seedlings to acclimate to the conditions of the outdoor environment.
To begin this process, start placing your seedlings on a porch or outside under a protective tree or shrub on days when the temperature is above 40 degrees Fahrenheit. It is especially important to always remember to bring your seedlings in every night, as the young plants are still quite fragile. After roughly one week of hardening off during the day, the seedlings will be ready to be transplanted into your outdoor garden permanently.
Squash are traditionally planted in hills separated by approximately three to six feet. Furthermore, each hill contains two or three squash plants. This is because squash plants tend to grow best when they are planted with “sibling” squash, as opposed to being planted individually in hills alone.
To begin transplanting your squash seedlings, follow these simple steps:
- Dig four to six holes into the side of each hill the same depth as your peat pots.
- Plant one transplant, including the peat pot, carefully in each of the holes. You are not removing the peat pots before planting because we do not want to harm the delicate squash roots. For this same reason, take care not to crush the biodegradable peat pots during planting.
- After placing the pot into the hole you’ve dug, pile the soil back up around the plant and water gently.
- As always, mulch with an organic material high in nutrients, such as grass trimmings or straw.
- Finally, when placing your squash plants in the hills, ensure they are located side-by-side as opposed to in a straight line. This will help encourage the pollination of the squash blossoms and the subsequent fruiting of the plant.
After your transplants have been in the garden for a week or so, it will be time to thin them to the two or three healthiest plants per hill. It’s vital to remember that squash plants grow quite large, and crowded plants don’t just struggle to produce fruit, but are more susceptible to disease. You can use scissors or pruning shears to cut off the plants you will not be keeping at the soil line. If you pull them, you risk disruption to the roots of the other squash plants.
Some “bush” varieties of winter squash can also be planted using the hilling method we have described above. “Bush” varieties of winter squash tend to take up much less space than their vining relatives and can be ideal for more compact areas.
However many more types of winter squash grow on vines and greatly benefit from the installation of a trellis to help support the weight of the fruit. When planting winter vining squash on trellises, be sure to leave at least four feet between each squash plant. Because winter squash does tend to grow larger than summer squash, if utilizing the hilling method, do make sure that you are leaving adequate space (approximately three feet) between each of your hills to avoid any future issues with overcrowding.
In order to prevent crowding and contain growth, it is also possible to plant either summer or winter squash in 15 to 20-gallon containers outdoors. Make sure to add drainage holes to the bottom of your container if necessary.
Direct Sow Squash
Another reason many gardeners love to grow squash is that the crop flourishes when started from seed directly in the garden.
For both summer and winter squash, wait until all danger of frost has passed. Then, create hills for your squash beds or utilize trellises if you are planting a vining species.
It is always critical to bear in mind the squash plant’s tendency to grow quite large. Due to this, remember to avoid overcrowding by allowing three to six feet between each of your hills. Also, you will want to leave six to eight inches between each of your squash seeds when planting.
- Start out by placing six seeds in each hill, approximately one inch deep into the soil.
- After placing the seeds into the soil, cover with dirt and water gently.
- After your seedlings reach approximately three to four inches tall, thin to the three strongest plants in each hill.
Again, remember to plant the squash next to one another, as opposed to in a straight line. This will aid in encouraging germination. Additionally, bear in mind that squash prefers to be planted in full sun and with well-drained soil that is rich in nutrients.
Be sure to amend your garden beds with plenty of compost and manure prior to the Spring planting season in order to provide your squash with all of the nutrition they crave.
Watering and Mulching Requirements
It is necessary to water your squash plants whenever the top inch of the soil feels dry. You can test this by poking your finger into the soil. When it is time to water, be sure to water gently but thoroughly. You want to ensure that the water reaches the deepest layers of the soil, which encourages the plant’s roots to grow deeper. This is important during the hottest months of the year so that the plant does not dry out.
Many organic farmers treat their squash plants with compost tea every two weeks during the growing season. This benefits any crops that are heavy feeders, such as squash.
Additionally, do not forget to mulch your squash after planting. Especially in hot climates, as squash has a relatively shallow root system, with the majority of their roots growing within the top twelve inches of the soil. This leaves them especially susceptible to heat, meaning they depend upon the extra protection provided by an additional layer of organic mulch.
Companion Planting and Rotation Considerations
The most important consideration when planting other crops around squash is whether or not the companion plants will share space well, or if they may contribute to the crowding issues already present.
For instance, crops which grow vertically are excellent companions for squash plants as neither plant will impede upon the other’s growing space. Because squash grows along the ground, they will also help inhibit the weeds which often plague the vertical-growing crops.
Examples of good companion crops include:
- Corn has the same soil moisture requirements as squash.
- Beans can be trained to grow up a trellis, while their roots fix nitrogen in the soil. This is very beneficial when planted alongside heavy feeders.
- Nasturtiums are known to “trap” certain pests such as flea beetles and aphids. This will prevent the bugs from attacking your fruit.
It is not a good idea to plant squash near potatoes, which are root vegetables that take up too many nutrients from the soil. Additionally, you do not want to plant your squash near pumpkins. As members of the same species, they may cross-pollinate in undesirable ways.
Common Pests and Diseases for Squash
- Powdery mildew is the most common ailment that squash growers run into in the garden. It is usually the result of overcrowding. And, the good news is that you can prevent it! Simply allow more room for air and light circulation around your plants. Moreover, try planting them further apart, or starting winter squash up trellises to allow for better use of smaller spaces, and to get larger vined fruit up off the ground.
- Anthracnose is an infectious fungal disease that spreads through moisture and can affect squash. However, you can treat it by spraying your crop with neem oil, an organic anti-fungal.
- Squash bugs lay amber-colored eggs on the underside of squash leaves. The eggs can look very similar to beetles. It is very important to remove these eggs completely as soon as they are discovered. They must be thrown in the trash or otherwise removed from the garden entirely, not just tossed a few feet away. If not removed from the garden completely, these bugs will find their way back into the squash beds. The best route is to remove the entire section of the leaf where these eggs are seen. If allowed to hatch, these bugs will most likely lead to an infestation.
- Vine borers bore holes into the vine of the squash plant, where they then live. This deteriorates the structure of the plant and leads to death. Look for small holes in the plant’s vines and tiny ridged burrowing worms.
Harvesting and Storing Squash
It’s important to harvest summer squash at just the right time. When left too long, summer squash is known to become quite bitter and mealy.
Many summer squash, such as zucchini, are even considered delicious when they are young, or immature. Typically these “baby” squash can fetch quite a high price in stores and farmer’s markets. However, if you are growing squash in your own garden, a good rule of thumb is to “pick young, and pick often.”
Squash flowers can be harvested and consumed, as well. To harvest the flowers, use pruning shears to cut the flower off of the stem an inch or two below the blossom. Remove the stamen before the flower closes and discard. The best time to harvest the blossoms is right before they are about to fall from the stem naturally.
Just be careful not to pick too many blossoms, as they are necessary for the pollination process which leads to the development of the squash fruit.
When harvesting the squash fruit also use pruning shears to cut the stem approximately one to two inches from the body of the fruit. Some squash may release with a gentle twist of the fruit, but any tugging on the stem could damage the plant.
Another important consideration with summer squash is its lack of shelf-life. Summer squash should be eaten as soon as possible after harvest. They will not store for more than a few days before beginning to rot.
Winter squash is harvested whenever the outside rind has reached a deep, solid color and the skin is hard. Never rush to harvest winter squash, as this will affect its ability to store. You will know that winter squash is ready for harvest when the vines begin to die back, and you cannot easily pierce the skin with a fingernail.
Usually, come September or October, you will harvest. This is to ensure they are harvested prior to the first frost. To start, use pruning shears to cut your squash from their vines, leaving about a one-inch stem attached to the fruit. Wipe any soil from the fruit with a soft cloth, and place somewhere that is between 70 and 80 degrees Fahrenheit for two weeks to cure. Once cured your squash should keep for three to six months.
Winter squash can be stored in any cool, dry place such as a basement, spare room, or even under your bed. Make sure you inspect your squash fruit every two weeks for any signs of spoilage.
Saving Squash Seeds
Squash crops are known to be ready pollinators, often crossing types not only within the designated summer and winter varieties but also often mixing summer and winter types together. These types of crossings will not be evident in the current season, but rather appear in subsequent seasons of squash fruit production. Because of this, if you wish to save a specific type of squash seed, you’ll need to take careful steps to separate your chosen squash plant(s) from any others that may interfere with or contaminate your crop’s genetic makeup.
- To begin, set aside space where you can grow two open-pollinated species of the same variety together in the same hill, away from your other crops.
- Once the plants start to bloom, cover them fully with a tent made of row cover or tulle in order to prevent the intrusion of any pollinating insects.
- For two weeks, hand- pollinate female flowers in the morning and then quickly replace the protective covering.
- After you see three perfect fruits develop on each plant, remove the protective tent and pinch off any new flower buds throughout the remainder of the growing season.
- Allow the seed-bearing fruits to ripen and harvest the fruit.
- Cut open your fruit and scoop out the seeds.
- Clean, dry and save the largest seeds from each fruit.
In ideal conditions, squash seeds should remain viable for up to six years.
Choosing A Squash Variety for Your Climate
There is an incredible variety of squash. In all actuality, there are so many that it would be impossible to name them all here.
However, we can simplify the task by breaking down squash the two main types.
- Summer squash includes many of the squash we are most familiar with enjoying as savory side dishes. These include yellow squash and zucchini.
- Winter squash are not actually grown in the winter, but rather can be stored to enjoy during the winter. These include butternut and acorn squash. Most often these are recognized for their hearty flavors and a wide variety of sweet and savory recipe applications.
Most types of squash can be grown in any region where the soil is fertile, drains adequately, and where there is plenty of sunlight.
Summer Squash Varieties:
- Yellow squash includes both straight and crooked neck types. They are an elongated shape and bright, buttery yellow color. Overripe fruit turns into warted gourds.
- Zucchini produces large crops, are club-shaped, and come in varying shades of green. Some are striped or bright yellow.
- Pattypan squash is an older variety. It is shaped like plump flying saucers with scalloped edges. They can range in color from dark green to bright yellow and white.
- Round and oval squash produce fruits on bushy plants that grow well in containers.
- Tromboncino and zucchetta squash are large, curvy fruits with pale green skin. These squash are naturally insect-resistant, and grow best on a trellis.
Winter Squash Varieties:
- Butternut squash is smooth-skinned, bulbous-shaped with sturdy vines. They are resistant to borers and not preferred by squash bugs. However, butternut squash does require 110 days of warm weather. This makes it less suitable for colder climates.
- Delicata squash is one to two pound striped, oblong, sweetly-flavored fruit. They are susceptible to vine borers and powdery mildew but not preferred by squash bugs.
- Acorn squash yield heavy crops of pleated fruits which weigh one to two pounds each. Most acorn squash is green in color, but some will ripen to orange or tan. They are susceptible to vine borers and may be seriously weakened by powdery mildew.
- Hubbard squash is sought after for their dry, orange flesh and stability in storage. They have long vines and grow best in the cool, damp climate of New England and the Upper Midwest. Additionally, Hubbard’s are susceptible to all squash pests.
- Spaghetti squash is fast-growing, prolific crops which produce heavily before powdery mildew can threaten their growth. Moreover, they thrive in a range of climates. Although, tine borers and squash bug invasion can become a threat to spaghetti squash.
- Buttercup squash is often grown as a substitute for the sweet potato in northern climates. This squash variety has vines that run approximately 15 feet and produce two to five-pound fruits. The buttercup squash is dense and contains a dark orange flesh that becomes flaky when baked, similar to a typical potato. These crops are moderately susceptible to pests and particularly well-adapted to the Pacific Northwest and Upper Midwest.
Additional Tips for Growing Squash Organically
- Hand pollination or otherwise incorrect pollination attempts before heavy rain or watering can result in improper fruit formation, including browning of ends. This will look like the fruit is rotting from one end.
- Never plant squash transplants that are “leggy” or already flowering in their pots. Seedlings that are already forming flowers in tiny pots will develop into stunted plants that produce only very small yields. It’s a much better idea to direct sow, or start your own seeds indoors.