Squash plant flowering
(left to right) Buckwheat cover crop to boost nutrients for a squash planting, Winter Luxury Pumpkin on Harvest Day, Acorn alongside a North Georgia Candy Roaster, Vegetative Squash plant sending out tendrils to explore and expand

Growing squash can be almost as much fun as eating it. The plants are large, vigorous, and adventurous- growing exponentially as they rapidly photosynthesize with their sometimes elephant ear-sized leaves. They transform from stunning starry blooms into fruit of all shapes sizes and colors before our eyes. This is the part of Squashin It’ where we delve into the cultivation of these horticultural delights.


Squash are native to Central and South America, with the some of the oldest domesticated specimens dating back 10,000 years. A staple for many of the first inhabitants of North America, it also became part of these cultures playing a key role as one of the “Three Sisters”; corn, beans and squash. Both winter and summer squash belong to the family cucurbitaceae, which is a larger amalgamation of various fruiting   plants including melons, cucumbers, pumpkins and gourds.

Start with Seeds

Quality plants start with quality seeds, seems simple enough, right? Cucurbits are, erm, rather promiscuous, with large flowers that require pollination to fruit, which makes them challenging to raise for genetically stable and uniform seed stock. To be clear, any cross-pollination between cucurbits would not result in a malformed or poor tasting fruit, just poor seeds for the next year. Techniques involving pollinating individual blossoms or using isolation tents have proven successful for those determined to save and breed squash on a small scale. Someday, at Jupiter Ridge, we would love to grow our own seedstock, (put it on the to do list), but for now we leave it to the professionals. Here are a few of our favorites!

Seed Savers Exchange

Located in outside of Decorah, Iowa about an hour from our house, is this gem of heirloom and rare seeds. Nestled in a valley with a beautiful trout stream running through the farm, these folks are committed to preserving heritage through seeds. Click here to view Seed Savers’ selection of SQUASH!

Johnny’s Selected Seeds

Headquartered in Winslow Maine, Johnny’s is a standard in the vegetable growing communty, with an extremely large selection of organic and conventional options. Our local rep, Nathan Belcher, is extremely helpful and loves to promote and interact with local farmers. Click here to view Johnny’s selection of SQUASH!

Territorial Seed Company

Territorial is located in Cottage Grove, Oregon. They produce 20 percent of the seeds they sell out in the hardscrabble lands of the Cascade Mountain Range, this speaks to the hardiness and vigor of the seeds they grow. The seed packets are beautifully illustrated and I am always excited to look through the box of seeds when it arrives on my doorstep. Click here to view Territorial’s selction of SQUASH!

High Mowing Organic Seeds

High Mowing’s 40 acre farm and test site can be found in northern Vermont but their seeds can be found in every corner of the country. They are staple and fallback for any grower looking for hard-to-find certified organic options for vegetable production. It is High Mowing’s goal to leverage the power of seed to transform our world. Click here to view High Mowing’s selection of SQUASH!

Soil Needs and Bed Prep

Both winter and summer squash plants are intolerant of cold and will die if touched by frost. This means a busy gardener will still have plenty of time to prepare beds for ideal soil conditions. I usually use this time to cover crop the beds with either a nitrogen-fixing legume or an easy to kill smothering crop like buckwheat which also mines and holds potassium which is necessary for flower and fruit development. Squash needs moisture-retaining soil with good drainage, this may seem like an oxymoron but is easily attained by making and planting into hills. On our farm I usually turn my cover crop in, then disc the beds into beautiful long rows with plenty of drainage. If you are planting in a non-linear fashion you can make individual mounds, you will generally want three to six feet between your hills, depending on predicted size of vine. Mulch, either straw or an inorganic plastic ground cover, is recommended to help keep weeds down and prevent rot where the fruit rests on the soil.

Squash seedlings on and poppin

Direct Seed or Transplant?

Squash seeds will not germinate if soil temperatures are below 60 degrees F, with an ideal germinating temperature being around a sweltering 85-95 degrees F. That being said, bring a thermometer to double check temps if you are going for an early seeding, better safe than sorry! Here in zone 4 in northeast Iowa, seems to be the last week of May or first week of June for earliest direct seeding, but the warmer the soil the quicker the seeds will germinate, and seeds can be sown all the way into July. Once you are in that golden soil temp range, you’re ready to roll. If planting individual hills place up to 8 seeds per hill, 1 inch deep, and thin down to 3 or 4 plants per hill. If you are planting in long rows, as I do, place two seeds every three to four feet in rows five feet apart. If you are planting a bush variety you can seed a little tighter. The seeds burst forth from the soil with much vigor and the cotyledon (first leaves) have the appearance of a small succulent when they first emerge. Soon enough, however, it will put on its familiar true leaves.

If you live in a place that has short summers, or if you just can’t wait for squash you can start plants indoors where the temperatures are steady and comfortable. Squash is fast growing and can quickly outgrow smaller plug trays, it also can’t hang with too much root disturbance, so I tend to use one 4-inch pot per plant and handle them gingerly. Many farmers and home garden enthusiasts seed into peat pots which can be planted whole, right into the soil with no root disturbance. When you are ready to plant dig a small hole in your hill and add a scoop of your favorite fertilizer, mix into the surrounding soil, place the the seedling in the hill and bury the plant just up to the base of the vine, being careful not to bury it to deep or splash soil on it, as this can spread disease. The last step is to make sure that your plant baby has plenty of water before you walk away, now you sit back and watch it take over your garden!

On our farm we implement both methods for getting our squash season started. Direct seeding is easy, quick, and (to me at least) a tactile treat! I love feeling the large, sometimes rough, sometimes smooth, somewhat heavy seeds in between my fingers as I toss them. We do our main squash planting by direct seeding because it is easier and less bulky than maintaining the requisite number of squash flats for transplanting. Transplanting does, however, have many advantages on our farm and as a part of our system. We start our early round of squash as transplants so we can be the first folks at market with squash, and to be able to do two separate rounds of curing (we will get into that later). Whichever way you choose to grow it the important part is that you are growing it!

Weeds, Weeds, Weeds

For those of you that mulched immediately, you will have spotty hand-weeding to do occasionally and I’m happy for you. For those of you that use chemical herbicides to control weed pressure, I don’t have anything for ya. For the rest of us it still isn’t all bad, squash is a relatively low maintenance plant, and if you time it right you can cultivate twice and usually skate through to harvest. I use a single row cultivator with a combination of rotary hoes and beet knives on the implement, we then go back through using tools to take care of the in-row weeds. I have a handful of tools I would recommend, all from Johnny’s. The first is a 22 inch tine rake, this removes lots of small thread-stage weed at once, the second is an 8 inch stirrup hoe, this cuts roots below the surface and mixes weeds back into the soil, and last but not least is the 7 inch collinear hoe, this is a flat blade at the end of a handle that allows you to cut weeds under the leaf cover and get as close as possible. Timing is everything, keep an eye on the squash, it will start to send out tendrils and grow in a more lateral way- this means the vine is about to “run”. The cleaner you can get the bed before the vine runs, the happier and more fulfilled you will be in all aspects of your life. Once the vine runs you are in! The vine will continue to grow and will create its own ground cover, keep watch for grasses and other weeds and pop them individually to prevent more aggressive plants from going to seed.

Humans aren’t the only ones who love squash… Photo credit Forrest Kelly, Onion Grove , Clarence Iowa