how to grow squash, cucumbers and other cucurbits, with tom stearns

I67RLS8fIVt4q6gmaFFnJ1tolu6zNPZ_SajrMEGgNScWITHOUT THEM, there would be no proper pickles, no pumpkin pies, no ratatouille. The melon-baller would sit idle, summer fruit salads undermined. Cucurbits are favorite food plants—but can be challenging. Don’t give up; learn how to grow squash, melons and cucumbers, with Tom Stearns.

Squash pests and diseases—from squash bugs, vine borers and cucumber beetles, to powdery and downy mildews and bacterial wilts—can make it all sound like just too much. But as a seed farmer, High Mowing Organic Seeds founder Stearns has to harvest lots of extra-ripe fruit to get his hidden-inside crop. He gets to the finish line by working to avoid any preventable setbacks, first and foremost, always keeping in mind the three key things about being a cucurbit:

  • You love heat.
  • You’re thirsty (but your shallow root system means you depend on the immediate area for water resources).
  • You love to eat.

Oh, and the aforementioned “issues” love you—some more or less depending on species and variety, or what region you garden in, or both.

Harvesting Winter Squash - Dave

step 1: provide enough consistent heat

ESPECIALLY in the early growth stages, says Tom (who farms in Zone 4B northern Vermont), never let a cucurbit cool off.

“If you put a seed in cold soil,” he says, “it will take three times the normal time to germinate—and it will come out of ground so weak and susceptible to disease and other issues.” Ideal soil temperature for cucumber and summer squash germination, for instance: 85F (with no sprouting below 60F).

Likewise, even if you start seeds in the cozy indoors on a heat mat and grow them under lights, but then transplant into cold garden soil, “the seedlings will just sit there.”

“Big reminder: heat,” says Tom.

Recommendations: Pre-warm the soil with black plastic sheeting for a week before the setout date (which is just after final frost). Transplant most cucurbits into slits cut in the sheeting after a headstart of 3-4 weeks indoors; watermelons at 6 weeks. (That’s a black plastic-covered squash row at High Mowing after harvest, above.) Many gardeners also cover cucurbit transplants with Reemay for extra warmth; more advice on that under “more pest protection,” below.

step 2: provide ample needed fertility

CUCURBITS are really heavy feeders. “You can’t really overfertilize,” Tom says, “the way you can with tomatoes and peppers, where you’d get only foliage by adding too much Nitrogen, at the expense of fruit set.” (Tom is an organic farmer, so he’s not talking about the potential for overdosing crops with fast-acting chemical Nitrogen, which can “overfertilize” or even destroy plants.)

“These are primarily vegetative plants,” says Tom. “Producing 10- or 20-foot-long vines compared to the amount of fruit per vine requires lots of fertility.”

Cucurbits are not too particular about micronutrients, he says. “I think of Nitrogen as the one they want if struggling. That’s tricky, because if the only source you used was quick acting–like foliar feeds of kelp or fish emulsions–a rainy summer can wash it down to depths that cucurbits can’t tap into.” If that happens, make another application of quick-acting foliar sprays, but remember: Compost and high-organic-matter soil help longer-term by making N steadily available to replace what may have leached. Don’t skimp on proper soil-building and top-dressing.

Recommendations: Cucurbits want a high-organic-matter soil. Topdress before laying down plastic with compost and/or organic fertilizer such as blood meal or alfalfa meal, then tuck a little more into planting holes. An extra benefit to soil-warming, weed-suppressing plastic: It limits nutrient leaching from rain.

Rotating where cucurbits are planted may help outsmart pests (though admittedly, rotation works better in a large-scale setting than small gardens). Rotation can also help provide for enhanced fertility. “We work hard to have the rotation for squash be in a good position–following a crop that’s putting down Nitrogen in the right form, such as after a pea cover crop,” says Tom.

step 3: water regularly, or else

EVER LOOK at the root system of a spent cucurbit plant while pulling them at cleanup time? Not much to speak of, relatively.

“Cucurbits can’t tap into resources that are much deeper than 6 inches,” says Tom. No wonder if the plant dries out it’s very stressful—another preventable potential setback.

Recommendation: Provide regular, thorough watering throughout the root zone, without waterlogging the soil.

Sivan melon

backing up: start with the right cucurbit variety

CHOOSING THE PROPER SEED is your first defense. Select a variety described as a good performer in your region. Seek out varieties that are bred for, or noted to have, superior resistance to pests and disease. With melons, says Tom, powdery mildew resistance is very important, for example, because the disease can really suck the sugar out of the fruit. (Melon growing, step by step.)

Also look for word in variety descriptions of exceptional vigor—since a wimpy plant that technically survives disease by just sitting there but with little fruit isn’t much help.

“Lately I’ve been paying attention to the vigor in different varieties—the plant’s adaptability and ability to handle lots of different conditions, to be resilient,” says Tom. “Sometimes when you breed for high disease resistance, if you’re not paying attention it won’t be very vigorous and produce much. If it’s really vigorous, however, it may outgrow the mildew and keep producing.”

'Butternut' squash after storing till springKnow the enemy’s preferences: For example, cucumber beetles love Cucurbita pepo varieties (including summer squashes, traditional pumpkins, and acorn types) and also C. maxima varieties (including many popular winter squash, such as buttercups, hubbards, turbans, kabochas, bananas)—but not butternut types (C. moschata, above) so much. Butternuts are also generally resistant to squash bugs, as are some others; again: read descriptions when buying seed.

Insights on insect preferences (such as for C. maxima) can also be used strategically on farms and in bigger gardens to plant a “trap crop” to lure pests to, perhaps sparing your main crop.

Short-season varieties may help you beat the problem clock. A must up North, short-season varieties can help Southern gardeners, too. Even where diminishing late-summer heat isn’t an issue, the shorter days-to-harvest means harvesting before mildew sets in, or before drought conditions weaken plants.

Recommendations: Select regionally appropriate, resistant, and perhaps short-season varieties where possible–and scan variety descriptions for hints about vigor, too.

squash bug

more pest protection

REMEMBER that a weak plant is a vulnerable plant; work to avoid any of the potential stressors explained above (too little warmth, water, or fertility).

Many gardeners cover all their cucurbits. With all melons in particular (and butternuts, to add heat), Tom says, cover with Reemay at transplant time, opening the tunnels or removing the fabric a week to 10 days after the first flowers appear, to allow for insect pollination. Reemay should be buried on the bed edges for complete control.

Seedlings at High Mowing that are not going to be covered are dunked in or sprayed with a kaolin clay solution before setout, to deter striped cucumber beetles. (One brand-name product is Surround.) Some transplants get both clay and a heat-increasing cover.

Planting successions of summer squash gives continuous harvest, and one generation may fare better against timing of pest or disease outbreaks. Transplant the first succession immediately after your frost-free day, with the final succession three months before predicted first frost. “It’s better to plant a couple of cucumber or summer squash plants every couple of weeks,” says Tom, “rather than depend on one planting.”

Prompt cleanup of vines and roots as fruit production declines is essential. Squash bugs (above), for instance, can even overwinter as adults; leaving debris in place longer than necessary invites a population explosion. (This new companion story with entomologist Diane Alston gives more detail on squash bugs and other pests.)

Recommendations: Mechanical barriers can help thwart pests organically, as can succession plantings and prompt garden cleanup.

some of tom stearns’s favorite squash and cukes

  • Summer squash: ‘Dark Star’ (a new Organic Seed Alliance collaboration), for its vigor; ‘Dunja,’ from a breeder in Holland, which is both highly resistant and high yielding; for grilling, Lebanese types (with paler skin, and fatter at the bottom) like ‘Segev;’ ‘and ‘Costata Romanesco’ and ‘Cocozelle’ for great flavor.
  • Cucumbers: Open-pollinated ‘Green Finger’ from Cornell breeding has a deservedly huge following, Tom says. Small-fruited ‘Picolino’ (below, meant to be picked as small as 3 or 4 inches, or as big as 5) and ‘Manny’ (below) are lunchbox-sized favorites for kids and adults, too.

enter to win the cucurbit seeds

I’VE PURCHASED three sets of four cucurbit varieties each from High Mowing–‘Dunja’ F1 summer squash and ‘Picolino’ F1 cucumber  and ‘Nutterbutter’ winter squash  and  ‘PMR Delicious 51’ melon–for three giveaway winners to try in their 2015 gardens. [UPDATE: The giveaway is now over. Your comments are always welcome, though.]

All you have to do to enter: Answer this question in the comments box at the bottom of the page, scrolling all the way down, after the last reader comment:

With cucurbits, what’s your hit, and your miss–the one you do best with, and then one that challenges you most, and why? (It’s fine if you report that you never fail, or totally fail, with all of them–just let us know, and tell us where your garden is, too. Favorite varieties, worst pests and diseases; let us know.)

(My answer: I always do well with Butternut-type squash in Zone 5B in the Hudson Valley of New York, but some years the longest-season C. maxima types don’t reach the finish line. I hand-pick insects and eggs vigilantly, grow all my cucurbits on black plastic, and do keep up with watering, too.)

No answer, or feeling shy? You can also just say, “Count me in” or something like that, and I will–but I’d love to learn more about your garden experiences.

Three winners will be were chosen at random after entries closed at midnight Sunday, March 22, and informed by email. U.S. only.

related stories:

(Disclosure: I’m proud that High Mowing Organic Seeds is an occasional seasonal advertisers on A Way to Garden.  Photos from High Mowing Organic Seeds, used with permission; squash bug and Butternut by A Way to Garden.)

  1. michal says:

    i grow cucumber on a trellis and summer squashes in raised beds. i’ve had luck with the beit alpha type and the lemon cucumber, but never enough space for melons and winter squashes

  2. Holly says:

    I am in the inland Northwest zone 5a. I have no problem with zucchini. Tried Minnisota Midget last year and did get a couple of fruit but the soil was too cold for a long time. Going to try the black plastic this year and see what happens.

  3. Alan says:

    I have a bug problem. So I went to Hobby Lobby fabric shop and got (89 cent a yard) white netting to cover plants. Right now Alabama z-6 has too much rain. I plant in half 55 gallon plastic drums. I will cover with plastic sheets tonight. We have rain till Tuesday. Strawberries will be waterlogged.

  4. Stanley Mccumber says:

    I love the yellow squash. Have had good luck with it. Like it fried, my wife’s favorite slice it thin and she makes the greatest lasagna, also sliced thin and breaded. em,em.em. One of the things I do is to hold the moisture and it saves a lot of weeding is I use old carpet all the way around the plant, with just room for the bottom of the plant to come out of. I only have about a foot of dirt otherwise I am on solid rock. so when dry I only have to water about once a week instead of everyday when it is hot, that old carpet sure does hold the moisture. Love it. P.S. I have tried hay, straw, black plastic, newspaper and the black cover that is supposed to retard the weeds. Nothing works as good as the old carpet and you can pull it up and use it next year. Takes little time to put down and takes up but sure saves he back on weeding and I have even put it down on the ground and cut a cross type hole in it and put my tomatoes and peppers in it, no weeding no tilling, just watch the plants grow.

  5. Julie T says:

    I do best with melons. And terrible with cucumbers. Either the fire ants or the beatles wipe me out of cucumbers. And it doesn’t seem to matter what trap crop I plant or variety of cucumber I plant. My winter squash grow wonderfully, but it has gotten too hot for them here in the desert. So climate change on that one. Am going to try planting 3-4 weeks earlier to see if that helps. Haven’t given up yet!

  6. Isabelle Legault says:

    Being in a 3b, and having close to 100 frost-free days, we tend to start our cucurbits in pots. H-19 Little Leaf doesn’t seem to mind that one bit and we love it for this reason. It’s so easy to see the fruits under those little leafs which makes a backbreaking job so much easier. In terms of fails, we have tried time and time again to get a large butternut (Waltham and other similar sized) to come to maturity but we always seem to get a frost right before the sweet spot. Oh well, we will keep to the personal-sized butternuts and that prolific and delicious Delicata squash.

  7. Pam says:

    Buttercup has been a great performer in our garden in Minnesota, zone 4a. I think one key to success with this is that I typically put the garden in late, and the squash last of all, so the soil is warmed up. Composted horse manure is applied generously before planting. Once the seeds are in, they seem to really take off and do well with little attention, and the area around the plant is mulched with dried grass clippings. After harvest and some outside curing time, the buttercup keeps well in our root cellar all winter. We typically use squash baked as a side dish and then use up the leftovers to make “pumpkin” pie.

    The curcubit that I haven’t had good luck with is watermelon. I tend to not spend a lot of time fussing in the garden, and watermelon seems to need more attention than I have given.

    Thanks for the great article!

  8. Joyce Mosby says:

    I do well with spaghetti squash. I still have some in storage!!! But I have difficulty with cucumbers every year.

  9. Julie Abramson says:

    I often save a few zucchini by doing surgery on them to remove the squash borer grubs; then I cover the stems with soil and often rescue them for further productivity. Sometimes, the surgery is a success but the patient dies.

  10. DIane says:

    my buttercup squash did famously in zone 4b Adirondacks. I planted them in old straw overlayed in a repossessed old bed. The spaghtetti squasha also faired well. Zukes are never a problem– unless you count what to do with them!! I have to say my melons—black mountain, minnesota midget , Halona etc. did NOTHING. Just sat there. I plan on covering the beds with black plastic (check!) and going from there. WIll plant in pots this week indoors.

  11. Susan says:

    It really depends on the year. Some years great success w/cukes and squash, other years good vines but little fruit, and some years, just awful all the way around. Hoping for good melons this year. Fingers crossed!

  12. Diane S. says:

    Planted cukes last year the leaves turned all mildew but the flowers were beautiful then a spotted beetle arrived .I ‘ve read once you have them they never leave.
    I did buy extra trellises maybe I’ll attempt again after reading all the good comments.

  13. Kristin Freeman says:

    Great article! Mostly successful with cucurbits, yet cucumbers are the big challenger every year. I learned much from reading this. Please enter my name in the drawing for seeds.

  14. Jennifer Schultz says:

    I can grow cucumbers like crazy. I have never had a problem with those. Pumpkins, cantaloupe, and watermelon on the other hand never seem to work out for me. I am in central Minnesota, which is either a zone 4A or 4B for my county. I have a 7500 sqft garden space. Thanks for the info about keeping the soil warm and about them being heavy feeders. This year I will try the black plastic and composted animal manure to plant them in. I water daily but may put the soaker hose on the melons and pumpkins to give extra moisture. So far this spring it has been warm and dry. I am hoping it’s not a sign of things to come.

    1. margaret says:

      Dry here, too, Jennifer…not the usual rain pattern (and last spring was very dry, worse than this year).

  15. Jean Yowpa says:

    I mostly grow Black Beauty Cucumbers in central NJ. The strangest thing with the weather situation and such, some years they don’t grow well and then like last year they produced abundantly. They always surprise me.

  16. Stella Neves Elbaum says:

    I’m in zonev6b in southeast CT. I’ve had years with great yield of cukes,acorn squash, pumpkins and butternut squash. It has to be a hot summer for melon to thrive. Constant issues with cucumber beetle, and haven’t found a solution yet. We put in a drip irrigation system and that’s been a help. This year we loaded on composted horse manure so well see if it makes a difference.

  17. Kristin says:


    Problem SQUASH BUGS – Anasa tristis- THOUSANDS OF THEM

    Current environmental laws PROHIBIT or prevent by expense for burn licenses- BURNING yard waste- (Anasas tristis overwinters in yard waste) burning old yard waste would greatly help in eradicating this PEST. Wood ash in itself is a pest repellent, and good for gardens

    POULTRY on my garden have helped extremely with the pests- they gobble up every thing that crawls, creeps or flies in sight. My chickens help far more than they hurt any plants I have. They say the squash bug gives off a noxious odor or spray to predators, but since Ive had the chickens I have seen NOT ONE squash bug on any of my curcurbits. Perhaps the chickens snap them up faster than the bugs can prepare their defense?

    Currently I am allowing a zucchini to go to seed, it is from an imported “Zucchini Striato d’Italia” that I have not seen ANY squash bugs attack. Whether it is the type of plant, the chickens, or when I planted it I am not sure. It is the first time I have ever had a curcurbit with no squash bugs.

  18. Carol says:

    I have planted Poona Kheera cucumbers annually since I discovered them 4-5 years ago. Young fruits are a pale cream color and are crisp, mild, and delicious. As the fruits mature they turn a darker golden yellow but still are perfectly good, not bitter. The most interesting flavor, however, comes when allowed to ripen to maturity, when they resemble a russet potato. At this point, while the peel and the seeds are better removed, the fruit develops an almost melon-like flavor. I also grow them at our Senior Center along with other kinds of produce to distribute to members and they are quite a conversation-starter!
    I also like Diva, since, being parthenocarpic, it may be grown under an insect barrier the whole season and because it is self-fertile, the fruits contain no seeds. A nice, mild-flavored cucumber.

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