How To Grow Organic Winter Squash?
ACTUAL FACTUAL INFO ON WINTER SQUASH
- Winter Squash could be considered a deceptive term considering that when you’re growing winter squash, it needs warm summer conditions to thrive. The term refers to this vegetable’s winter storability, not the time of year in which it grows.
- It is believed that cultivating and growing winter squash began in Central and South America 8000 years ago.
- The word “squash” was derived from the Narragansett Indian word “askutasquash” – meaning “a thing that is eaten raw.”
WHEN TO PLANT WINTER SQUASH
- You’ll need about 80 to 120 frost free days when growing winter squash to allow it to reach maturity.
- You can begin growing your winter squash indoors about 4 weeks before your last predicted frost date.
- If you use row covers, you can transplant winter squashes to your garden one or two weeks before the last anticipated frost.
- If you live in warmer areas you can plant your seeds directly in your garden after the danger of frost is past, typically around the end of March or mid-April.
- You’ll want to plan to have your winter squash mature by late summer or early fall.
WHERE TO PLANT WINTER SQUASH
- Squash needs, at the very least, six hours of full sunlight every day.
- Winter squash requires soil that drains well and has lots of organic materials blended into it.
- Your soil ideally should have a pH balance in the range of 5.8 to 6.8, although many gardeners have been successful with slightly alkaline soils.
- Your soil should have sufficient levels of nitrogen, phosphorus, and potassium, most of which are achieved with the liberal application of compost and/or composted manure, bone meal, blood meal, and the like.
PREPARING YOUR SOIL FOR GROWING WINTER SQUASH
- Winter squash needs lots of soil nutrients which can be supplied mainly with compost and composted-manure.
- The best way to apply your compost is to lay out where your hills will be and mix several inches of compost into about a 2 foot diameter area about a foot deep.
- You can also mound the soil where your plants will be to aid in the mixing in of compost or other organic matter.
- Other items you can add to your soil are alfalfa meal early in the season for nitrogen, and feather meal later in the season, ground oyster or egg shells for calcium, greensand for potassium, and kelp meal for trace nutrients.
CHOOSING THE RIGHT SEED VARIETIES FOR YOUR AREA
- If you have a small garden, grow bush varieties like delicata or acorn. These squash can be trained to a trellis to save space.
- Larger varieties are too heavy to trellis and grow well in larger garden areas.
- Contact your county extension office to find out if there are common diseases in squash in your area. If there are, get recommendations for seed varieties that are resistant to those diseases.
SEEDS AND GERMINATION
- Winter squash seeds are good for up to six years after you’ve harvested them or purchased them from your seed supplier.
- Winter squash seeds will not germinate in soil temperatures lower than 60°F or higher than 100°F. The optimal germination temperature is 86°F to 95°F.
- The seedlings should emerge in about 5 days at this temperature range if they are in full sunlight or under grow lights (fluorescent lights will work OK).
- If you’re seeding directly to your soil, you can use a black plastic mulch to heat up your soil.
- Secure your plastic with soil (make sure all edges are covered with dirt), and cut holes for seeds.
- Your garden soil temp should be no lower than 60°F to 65°F to germinate your seeds.
GETTING STARTED INDOORS (and transplanting)
- Plant your seeds in peat pots or soil blocksor other containers 3 or 4 weeks before the last frost. You can use tapered plastic pots as well, but peat pots are your best option.
- Use a good potting mix or starter mix to start your squash seeds in. These mixes are readily available at your local garden center. We recommend a local store over national chains as they usually have a specialist that has more knowledge than your average chain store employee.
- If you want to create your own potting soil mix, you can purchase mixing loam soil, sphagnum peat moss, and perlite at your local garden store. Adding compost to this mix will create a great starter mix.
- Don’t use garden soil as it has lots of weed seed, fungus spores, and bugs in it that aren’t optimal for starting your winter squash indoors.
- If you want to grow a squash plant or more in containers, you’ll need to get a 10 gallon pot.
- Mix 9 gallons of potting mix, a couple cups of alfalfa meal, half a cup of feathermeal, half a cup of powdered eggshells or oyster shells for calcium, half a cup of greensand for potassium, and a few tablespoons of kelp to cover your trace minerals.
- Plant three or four seeds about 1″ deep. Don’t thin until the plants have at least 2 true leaves; leave the 2 best seedlings and after one is about 10 inches tall, choose the best plant and clip the other off with a scissor.
TRANSPLANTING YOUR WINTER SQUASH TO YOUR GARDEN
- To harden off your plants, move them outside during the daytime and cut back on watering.
- Your plants should have 2 or more true leaves at this stage and it will have been 3 to 4 weeks since you originally planted them.
- As squash prefer warm temperatures, ideally the daytime temps will reach 75° to 85°F and nighttime temperatures around 60° to 65°F.
- However, if you live as far North as we do, you may not hit those temperatures until 2-4 weeks after transplanting, so it might be wise to use row covers and black plastic mulching to help your squashes get a good start.
- You need a minimum soil temp of 60°F to plant your squash.
- If you’re planting in rows, space the rows 4 to 6 feet apart and the plants about 2 feet apart in the rows. If you have vining squashes, you might want to plant them 3 to 4 feet apart in the rows.
- When you plant your squash seedlings, dig a hole large enough to place the peat pot or soil mass that will slide from a plastic pot into and pack soil around the plant.
- Make sure the soil is moist but not too wet; you should not be able to pack a tight dirt clump with your hand or it’s too wet.
PLANTING DIRECTLY TO YOUR GARDEN BED
- Once your soil temps have stabilized above 60°F, you can plant winter squash seeds in your garden. You should make sure that you’re past the danger of frost.
- If you’re hilling your squash area, make your mounds about 4 to 8 feet apart and plant 4 to 6 seeds about one inch deep and about 1 inch apart in a circle or square configuration.
- If you’re planting in rows, the rows should be 4 to 8 feet apart, and the seeds should be planted 6 to 12 inches apart.
- Once the seeds have germinated, you can thin your plants to one every 18 to 36 inches, depending on whether they’re bush or vine varieties and what your garden soil can handle.
SUCCESSFULLY GROWING YOUR SQUASH IN YOUR GARDEN
- Once your plants have at least 2 true leaves, thin them to 2 or 3 plants per hill, or 18 to 36 inches apart if they’re in rows.
- Squash has male and female flowers. Male flower will appear first, 40 to 50 days after germination. A week later female flowers will begin to emerge.
- If you have plenty of insects, pollination should be no problem.
- If you have too few insects, you’ll see the female flowers begin to drop.
- To avoid this, you can hand pollinate them yourself. Use a cotton swab to gather pollen from the male flower and distribute it onto the centers of the female flowers.
- Early in the season, you’ll need to make sure the squash plants are not choked out by weeds.
- Hand pull any weeds within six inches of the squash plants, then surface hoe the weeds that are further away, and rototill weeds more than a foot away from your squash plants.
- Once the vines have covered the ground, you’ll not need to weed much in your squash patch the rest of the season.
- It’s a good practice, about half-way through the season, to side dress your squash plants (about 6 inches from the base of the plant) with compost, composted manure, or alfalfa meal.
- It is a good idea, if you have squash borers in your area, to mound dirt around the base of your plants to discourage them from laying eggs.
- Jenny’s Tip – When you’re growing winter squash, spray them with a liquid organic leaf spray fertilizer. We highly recommend Organic Garden Miracle™. OGM™ naturally stimulates your garden plants to produce more plant sugar in the photosynthesis process. That in turn creates a more robust plant, more produce from your garden, and better and sweeter flavored squash. And they have a really good warranty!
WEEDING & MULCHING
- Straw or grass clippings, spread around your squash plants, both help to conserve soil moisture and throttle pesky weeds.
- You won’t want to apply these types of mulches until the soils reach about 75°F as they will have a tendency to keep your soil cooler.
- One of the biggest assets of mulching is that because squash have shallow roots systems, you don’t have to disturb them much by weeding if there is mulch around your plants.
- Depending on your climate, winter squash will need to be watered between 1 and 2 inches weekly.
- If you mulch, you can use somewhat less water, but do check your soil’s moisture level often during hot, dry spells.
- If you water weekly, especially if you’ve mulched, that should be adequate.
- Water enough when you do water to get about 6 to 8 inches into your soil. Light watering of squash is virtually useless.
- If your soil is sandy, use less water but water a couple of times per week.
- If your squash is trellised, you may need to water a bit more than if the plants are sprawling over the ground.
- As with most vegetables, drip irrigation or soaker hoses are the best watering method. However, if you only have overhead sprinklers, water early in the day so as to reduce risk of fungi and mildews.
COMPANION PLANTING AND ROTATION CONSIDERATIONS
- Good companions for Winter Squash include:
- Beans which supplement your garden with nitrogen that it absorbs from the air.
- Corn works as a trellis for squash as one of the “sisters” in Three Sisters Planting.
- Radishes are reputed to protect your winter squash from squash borers by attracting them away from your squash plants; the borers don’t harm the radishes.
- Mint is said to help control ants, aphids, flea beetles, and rodents.
- Onions ward off fruit tree borers, weevils, aphids, rust flies, moles, and some root nematodes.
- Marigolds and Nasturtiums repel bugs and beetles away from your squashes. They also attract bees which help to pollinate your squash flowers.
- Oregano is also said to benefit squash in keeping away many pests.
- The one Bad Companion for winter squash are potatoes. Potatoes inhibit the growth of squash plants.
- You don’t necessarily need to rotate squash annually unless you’re having issues with verticillium wilt, mosaic virus, or other diseases.
HARVESTING WINTER SQUASH
- Squash matures typically late in the summer or early fall. If you have a particularly cool summer as we did last year, much of our squash crop didn’t mature.
- You can tell when squash is mature by using the fingernail test. If you can easily puncture the squash’s skin, it’s not mature.
- In our area, we typically wait until the first killing frost hits to harvest our squash. It makes them easier to find!
- Some recommend harvesting before a heavy frost (below 26°F) as it may damage the squash. Keep an eye on your local weather forecast just in case your first frost is heavy.
- I use a pruning shear to separate the stem from the plant. I leave 2 to 3 inches of stem on the fruit to keep the squash from rotting in storage.
- The longer you can leave your squash in the field (even after a light or killing frost), the better. This allows the skins to toughen and makes for a better storing fruit.
- If this isn’t possible, like it often is not in our area, move them indoors to a dry, warm, and well-ventilated location(80°F is ideal). If you have them in this environment for about 10 days, the squashes should store quite well through the winter.
WINTER SQUASH STORAGE
- Winter squash gets its name primarily because it does store well through the winter. We’ve often still had good squash clear into April if the above procedures are followed.
- Once this toughening phase has been completed, the best storage temps will be around 50°F at 60% humidity. Cool, dark, and fairly dry are the best storage rules for squash. A basement area, dark space in your garage, a crawl space under your home, or a root cellar are typically ideal locations for squash storage.
- Although, we have had just as good of success storing it all winter at room temperature. See Jenny’s post in Farmer Brown’s Journal.
- Some squashes may have been bruised or cut during harvest or when moving into the storage area.
- These will sometimes rot more quickly, so it’s a good idea to take a look at your squash every few weeks during the winter and remove any squash that may be developing “rot spots.”
- You can cut out the rot spots and bake, steam, or otherwise cook these squash with no negative effects to the flavor or nutrition of the remaining squash portions.
- You can steam and freeze squash or even can squash if you don’t have an appropriate storage location.
- Caveat: it may be difficult to get the squash hot enough to kill all the bacteria that is recommended if canning a puree, so it’s best to cube the squash and can it in a little sea salt and water.
- We have experimented with squash and kept it in warmer areas of our home at 65° to 70°F through the winter and still had plenty of squash to eat all winter.
PREVENTATIVE AND NATURAL SOLUTIONS TO COMMON PESTS AND PROBLEMS
- Cucumber Beetles are a striped beetle that is about 3/16″ in length, greenish yellow, with three black stripes running down it’s back.
- The spotted cucumber beetles is pretty much the same but with a dozen spots on it’s back.
- Regardless of what these beetles look like, they’re pretty nasty pests that eat your plants and spread bacterial or verticillium wilt to your plants.
- To prevent these beetles from getting to your plants, you can use row covers before flowering to keep them away from your winter squash plants.
- If the problems get too serious, you can use organic pyrethrins or organic rotenone to deal with these critters.
- Another nasty pest is the squash vine borers. They typically appear about the time the vines begin to spread out across your garden.
- Squash vine borers are an inch long or so, quite fat, and are white with a brown head.
- They are the larvae of a small moth with dark front wings and light rear wings and a red abdomen. The moths lay eggs in the late spring or early summer near the base of your squash vines.
- The borers appear about a week later and drill a hole in your vine to get inside them. You’ll see a small hole and green excretions below the hole. And you’ll see the vine die rather suddenly.
- To prevent squash vine borers from decimating your crops, first, watch for the moths (and listen…they have a buzz when they fly that’s unusual for moths).
- You can also use yellow-colored bowls filled with water to trap these moths; they’re attracted to the color, and will fly into the bowls and drown.
- Alternatively, it’s a good idea to use row covers for about 2 weeks until the moths disappear again. Make sure you cover the edges of the row covers with dirt to seal out the moths.
- If your plants begin flowering during this time, you can hand pollinate your squash if necessary. Don’t use insecticides as they can also kill beneficial insects that pollinate your crops.
- If you discover the borer has created a hole before the plant wilts and dies, you can sometimes carefully cut a hole in the vine and remove the borer. Cover the vine and the hole with dirt as it will many times send roots into the soil from the cut area.
- If you find a vine that’s been killed by a borer, cut back the vine and destroy it.
- Aphids are also common pests that can be found on the undersides of your squash leaves. You’ll know they’re there if you see leaves turning yellow and crinkling or curling.
- Aphids suck the juice from your plant leaves and leave a sticky substance behind. The only beneficiary of this process is ants, who harvest the sticky sweet stuff.
- The best solution to aphids is to import ladybugs to your garden. They feed on aphids and are very effective in ridding your plants of these little green bugs.
- Another solution is to “wash” them off with a hose and high-pressure spray nozzle or an organic insecticidal soap.
- Squash Bugs are probably the most prevalent pest but are somewhat easier to control than borers. They suck the sap from the squash plant leaves, leaving them initially speckled; then the leaves wither and die.
- Controlling squash bugs is easier if your soil has lots of nutrients and your plants are healthy.
- Get rid of anything around your garden, such as old boards or anything they can hide under during the winter.
- It also helps to rototill or turn under your garden in the fall to eliminate places these bugs like to hide in.
- To get rid of the bugs, hand-picking usually works in a garden as it’s not so large as to take more than an hour or two per week for a few weeks in the summer.
- When you pick these bugs and nymphs, have a pail of soapy water to drop them into…the soap breaks the capillary action of water so the bugs immediately sink and drown in the water.
- If you find eggs attached to the underside of leaves or stems, simply crush the eggs.
- Lay a board or two in your squash area overnight…the bugs will congregate under the boards at night. In the morning, lift the board and capture the bugs and drop them into the soapy water pail.
- Organic compounds such as rotenone and pyrethrins are also effective if you have a heavy infestation of these varmints.
- Blossom-end rot causes your fruit to develop a black rot on the end of the squash. Hot weather/lack of water, and a calcium deficiency, are the main cause of the rot. It can be prevented by making sure your plants have water and if necessary, add lime to the soil before watering.
- Downy mildew is a leaf disease and is caused by a fungus with a long Latin name. If you really want to know the name, let me know and I’ll copy and paste it in a reply.
- This mildew usually isn’t a problem unless you have a cold spell in the 45° to 55°F range for a month or longer.
- The mildew shows up initially as yellow patches on your squash plant’s leaves, then turns brown or tan with gray or white downy fuzz below it. Then it progresses to black patches and the leaves and sometimes the plants shrivel up and die.
- To prevent downy mildew, grow squash varieties that are resistant to it.
- Also, allow space between your plants so they don’t stay wet too long.
- And if the conditions appear favorable for the disease to appear (i.e. a long cool and rainy spell), spray your leaves with a compost tea. To make the tea, put compost in a bucket and fill it with water; when it settles out, fill your sprayer with the brownish water and spray your plants leaves with it.
- Powdery mildew is another mildew that can affect your winter squash plants, but looks entirely different. It’s whitish and powdery and grows on squash leaves and stems.
- It is also caused by wetness, but warmth and humidity rather than cool weather and rain.
- If the leaves are infected, they’ll usually die. If the infection is severe, it can kill the whole plant.
- If you are able to, avoid overhead watering. If not, water early in the morning so the plants can dry out by noon or so.
- If you keep insect pests under control and spray your vines and leaves with a compost tea solution or a baking soda solution, you most likely won’t have an issue with this disease.
- Other solutions include organic sulfur sprays or a weak solution of milk and water (9:1).
- If you spot any of this mildew, destroy your vines at the end of the season and rotate your winter squash to a new area next gardening season.
- You can also purchase seed varieties that are resistant to fungi such as downy and powdery mildews.
- Another fungus with a long Latin name causes a blight called “black rot.” Black rot is found mostly in warmer and more humid climates such as the Southeastern U.S., but can also show up in winter squash and pumpkins in the cooler climates.
- Black rot is a gummy blight that attacks the stems and leaves of squash plants. It is usually brought on by too much moisture.
- Black rot will survive on dry plant matter or in the soil. It will live there for over a year.
- It lives on dry plant material or in the soil, where it can survive for more than a year. It is necessary to rotate your squash crops to a new area if this blight hits your plants.
- To avoid black rot, irrigation should be managed to minimize free moisture on leaf surfaces, and a minimum two-year rotation cycle is a must.
- Again, overhead watering should be avoided, but if you have no choice, water early in the day.
- You can also make an organic fungicide spray using bicarbonate of soda (baking soda). In a gallon of water add a couple drops of organic olive oil, a couple drops of environmentally-friendly liquid soap, and 3 tablespoons of baking soda. Spray it on your squash leaves to effectively control all of the above fungi.
Various names of Winter Squash varieties
- Winter squash includes a list of squash a mile long: Hubbard, Butternut, Delicata, Ambercup, Arikara, Atlantic Giant, (Pink) Banana, Buttercup, Georgia Candy Roaster, Jarrahdale Pumpkin, Kabocha, Lakota, Mooregold, Red Kuri/Hokkaido, Rouge vif d’Etamps, Turban, Cushaw, Long Island Cheese, Acorn, Carnival, Gem, Heart of Gold, Spaghetti, Sweet Dumpling, Autumn Cup, Calabaza, Cushaw/Winter Crookneck Squash, Giraumon, Gold nugget, Marina di Chioggia, Queensland Blue Pumpkin, and Sugar Loaf Squash. If you know of others that I’ve missed on this list, please send their names to me on our contact form.
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