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Growing Cucurbits from Seed

19dbdbca-5cc2-4034-81d9-0d9869c64690The Cucurbitaceae family occupies so many summer meal fantasies: juicy watermelons, sweet melons, crunchy cucumbers, versatile squash. As your last spring frost dates nears, get a jump start on Cucurbit production by sowing seeds indoors or in a greenhouse. Or, if you aren't in a hurry, get to know how to sow seed directly and plant your cuke, zuke, melon, and (later in the season) pumpkin seeds right in your garden bed.

Our Best Seed Starting Tips for Cucurbits:

1. If starting indoors, start seeds 3-4 weeks before desired transplant date. Your transplant date should always be on or after your last frost date, up to 4-6 weeks later. Later plantings than that will produce fruit but will not have enough time to produce a good crop.

2. Sow 1 seed per cell, 1" deep. We like using cells that measure about 2x2x3" for summer and winter squash, and one a bit smaller for melons and cucumbers. The aim is to transplant seedlings right after they have healthy set of their first true leaves, so they are generally only in their pots for about 3-4 weeks. However, they grow so fast, allowing for a tad bid of extra space in their cells keeps them from getting stressed if you have to wait.

Double Yield Cucumber

Double Yield Cucumber

This high-yielding cuke does double duty.

Sugar Baby Watermelon

Sugar Baby Watermelon

Oh Baby! Compact & sweetly mouthwatering.

 3. Keep them in direct sun, in a warm spot. Cucurbits need very warm temperatures to "pop" quickly. Place them on a heat mat, or in a very warm spot. 70-80 degrees is the best temperature range. After seedlings emerge, be sure they are in DIRECT SUNLIGHT.

4. Watch out for rodents! If allowed, rodents will certainly dig up and eat all your seeds before they germinate, especially melon and squash seeds. If rodents have access to your seed starting space, cover the cells with screens until the seeds start to germinate.

5. Keep an eye out for cucumber beetles too. Cucumber beetles can be an issue in the greenhouse and the garden in the early spring. Keep seedlings high on a table and cover with very light row cover if you think you might have an issue.

Blue Kuri Squash

Blue Kuri Squash

A delectable favorite with dry, cake-like flesh.

6. Try direct sowing! Direct sowing cucurbit seed is an easy way to start them. Direct-sown plants can even catch up to transplants, if you sow them asap after threat of frost has passed. Another great benefit to direct sowing is that by forcing them to emerge in the outside elements you will be selecting for strong emergence and vigor. To direct sow: Check the final spacing requirements for the variety you are growing and sow seeds at double to triple density. Then thin to the most vigorous seedling after they emerge.

Variety Recommendations


For small spaces and container gardens try:

Winter Squash: Cornell's Bush Delicata this true bush habit winter squash and takes up the least amount of space out of all our winter squash varieties. Expect 2-5 fruits from each plant.

Cucumber: Homemade Pickles Cucumber though this variety vines, they are short and very controllable. Can also be grown in containers.

Summer Squash: Cocozelle Zucchini is the most compact zucchini we offer. Plus, this variety has the best flavor.

For something new:

Winter Squash: Violina Rugosa needs space and time, but it's well worth it if you can spare it! Large warty fruits encase sweet, smooth flesh with outstanding flavor.

Cucumber: Yamato Sanjaku is a long, thin skinned cucumber, and a near and dear variety to the staff here. We recommend trellising for straight, easy to chop fruits.

Watermelon: Sweet Siberian Watermelon is our favorite watermelon for flavor and color! The bright orange glow flesh is cooling on a hot summer day.

Melon: Banana Melons are unlike any other melon! The looks don't take anything away from the flavor. It's not banana-like, but it is one of the best tasting melons out there.

IMG_2228For market gardens:

Winter Squash: Waltham Butternut is one of those classics that just keeps on being great. High yielding with quality fruits and great flavor.

Cucumber: Silver Slicer white cucumbers are novel but do not disappoint. Sweet, pleasant flavor lacks bitterness, plus this variety was bred by Cornell University breeders to be Powdery Mildew Resistant.

Summer Squash: Dark Star Zucchini shines in less than ideal conditions. Classically bred for uniformity, yield and drought tolerance.

4 thoughts on “Growing Cucurbits from Seed”

  • Dee

    I would love to have some instructions for how to control cucumber beetle on young and maturing plants in the garden. I have had serious problems with these insects and so far have not found a great way to stop them. Thanks

    • Erin

      Hi Dee--We've actually got a very informative blog post all about cucumber beetles and how to control them! http://www.seedlibrary.org/blog/bug-profile-cucumber-beetles/

  • Jennifer

    How about something natural to help fight the squash vine borers???? Ugh!

  • Deb Parker

    I had good luck planting icicle radish at the same time I planted my cucumber and squash seeds. Let the radish get big (unusable)then flower and go to seed. The squash borers seem to get confused by the smell, or maybe it attracts natural buggy enemies, it seemed to work really well in my 2015 garden.
    Plant companion plants,a trellis' of climbing beans among the squash. Plant aromatics like dill near the cucumbers as well as the radishes.
    Rotate, rotate, rotate, don't plant in the same place as last year! It can be hard if space is limited. Or exposer to sunlight, which is the problem I have in my garden.
    Lay down plastic mulch, silver or a reflective mulch is said to be good. Still need to be vigilant.
    Or place boards under the squash and step on the adult squash borers in the morning. Pick and destroy leaves with eggs, not placed in compost, (by the time I see the immature bugs it's too late)!!
    Also plant squash varieties that are more resistant to squash borers, I found butternut to be better. There are small "personal" varieties that can be grown in a large container, and trained to grow up a sturdy frame or fence, so borers won't get them.
    There are omri approved sprays, (captain jack dead bug juice is one), but must be applied as directed on label, days to harvest is listed on label as well. That's all I got!!


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