Tags: Certified Organic Open Pollinated

Growing Practices: No Pesticides No Herbicides No Fungicides No Synthetic Fertilizers

Latin Name: Cucurbita moschata

Days to Maturity: 110


Downy Mildew resistant butternut from the fifth generation of a cross between Waltham butternut and Seminole pumpkin. Intensively selected for eating quality, Downy Mildew resistant foliage, yield and shape.

Edmund Frost has been working with this seed since 2011, starting with a cross between Seminole Pumpkin and Waltham Butternut. The variety name will be South Anna Butternut (named after the river that runs past Twin Oaks Community in Louisa, Virginia) though we're not quite ready to call it that.

In 2016 (with help from a SARE grant) we intensified the selection work, growing 108 plants, all trained and evaluated separately. We are selecting for Downy Mildew resistance, productivity, eating quality, brix, dry matter, keeping quality, and butternut shape. This seed comes from the best 17 plants from 2016, and should be a significant improvement over the F5, especially in terms of eating quality (as measured by brix tests, dry matter tests and tasting).

While improvements will continue through 2018, we are quite excited about the progress made to date. Expect 90% butternut-shaped fruits, with good productivity, Downy Mildew resistance, rich sweet flavor, and good keeping quality. Immature fruits vary between light and dark green in color (most immature butternuts are light green). The dark green ones take longer to turn fully tan, but when they do you can be sure that they are ripe.

This variety will avoid the crop failure that can occur in years when Downy Mildew comes early, and provide higher yields in years with average DM pressure. The healthier foliage also leads to better fruit quality, with sweeter, riper fruits of a rich tan color. When used as a late planting, South Anna grows strong until frost, allowing for later harvests that will keep better into the winter and spring.

We've pledged Seminole-Waltham F6 as an Open Source Seed Initiative (OSSI) variety. OSSI is a movement to help protect seed from corporate monopolization. Read more at osseeds.org. Not commercially available elsewhere. Grown at Sycamore Farm. Certified Organic by Baystate Organic Certifiers.

Questions 8 Total

Ask a Question About Seminole-Waltham F6 Butternut Squash

  • Answer this question

    How long are the vines? Because my garden is small, I trellis all of my vining crops. But I learned the hard way that some squash vines can grow 50 feet long - way too long to trellis!

    Posted by Debra Graff on 09/18/2017

    Answers 1

    • These have long vines. It would take a very strong trellis, such as a cattle panel arch. On the flat I use 9 foot row spacing. Don't be shy about training or cutting vines that are starting to go where you don't want them to.
      Edmund for CWSG

      Posted by A Seed Growers Cooperative on 09/19/2017

  • Answer this question

    hello, i would like to cross my tromboncino squash with your seminole x waltham (i'm looking for a long skinny squash that tastes like butternut when mature). i don't know the longevity of squash pollen, but if you'd want to send me some pollen, i would be more than happy to send you some F1 seeds back in exchange (if the pollen happens to survive the trip.) thanks!

    Posted by Carrie M on 08/29/2016

    Answers 1

    • I don't think the pollen would make the trip, though I've heard you can keep a male flower in the fridge for a couple days.
      We have some seminole pumpkin that crossed with tromboncino accidentaly, so maybe I'll look into that, starting with some attempts at self pollination (its getting late in the season) and then some taste tests of the cross. I also have a couple seminole-waltham plants with long skinny necks that I could work with (if they do decently on eating quality tests).
      Thanks for the offer and the idea. Edmund for cwsg commonwealthseeds@gmail.com

      Posted by A Seed Growers Cooperative on 09/01/2016

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    How many squash do I need to save seeds from to maintain genetic vigor in future generations? I have about 25 plants that are all doing great! Is that enough to maintain genetic diversity and strength or would it be beneficial to buy more seeds to plant next year alongside the seeds I save from this year? Thanks for such awesome seeds!

    Posted by Elisha Somerville on 09/12/2015

    Answers 1

    • Elisha,
      Since this is a variable population its ok to save seed from only your favorite few plants and to keep selecting from there each year to get (or maintain) what you want. (In a stable variety I would recommend at least 10 cucurbit plants but I think even then you can get away with less for a generation or two). Each Seminole-Waltham plant has a lot of genetic variation in it at this point. Also, each fruit has seeds whose male parents are many or all of the plants in the patch. Cucurbits do not have much inbreeding depression like corn or broccoli. In fact, many cucurbit varieties have been bred using repeated self pollinations of single plants (though many lines are tried during this process). This technique narrows the genetics much more than selecting from fruit that has multiple male parents. Some breeders believe that incorporating more plants and more genetics will yield a more resilient variety however. In any case if you're not self pollinating and you're saving seed from a few favorite plants there will be plenty of genetic diversity maintained here.

      Posted by A Seed Growers Cooperative on 09/13/2015

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    Edmund, I am getting a good harvest. Some of the baby squash are dark green with butternut shape and some are light green with Seminole pumpkin shape. They are charging through Downey mildew that has killed the Waltham butternuts. Tromboncino and Palav Kudu are also not bothered by mildew. All other cucurbits are dead!

    Posted by Marcus E. Smith on 08/25/2015

    Answers 0

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    My first planting of these failed to germinate due to cool wet April conditions, Replanted May 9 and have 2 fruits both very dark green and looking like Seminole pumpkins, Just letting you know, no butternut shapes yet.

    Posted by Marcus E. Smith on 07/14/2015

    Answers 2

    • I now think I mixed these with another squash seed. Mine have classic young butternut coloration.

      Posted by Marcus E. Smith on 07/24/2015

    • I now think I mixed these with another squash seed. Mine have classic young butternut coloration.
      Further Internet research shows pics of the same dark green color in immature Seminoles so gues I will wait and see if they ripen to butternut tan. I'll say this, they have taken over the trellis going up 6', back down and over three rows!

      Posted by Marcus E. Smith on 07/25/2015

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    Does Seminole Waltham winter squash need to to have something to climb up? And how much space between plants?

    Posted by Debra Cox on 05/10/2015

    Answers 1

    • Two to three feet between plants and nine feet between rows.... While they will climb all over the place, they can be grown on the flat.

      Posted by A Seed Growers Cooperative on 05/10/2015

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    Is this seed the F3 from an F2 selection, or is it the F4 from an F3 selection?

    Posted by Deirdre Birbeck on 04/08/2015

    Answers 1

    • This seed was selected from F2 generation plants in 2013. We planted and observed the F3 generation in 2014, and entered it in our winter squash variety trial. We have F4 seeds currently (selected from the F3 generation) but not enough to sell. Next year we should have F5 seed for sale (in bulk as well as packet sizes).
      Edmund for CWSG

      Posted by A Seed Growers Cooperative on 04/08/2015

  • Answer this question

    Do you have any more of this in stock? I want to order but can't because there isn't any in stock...


    Posted by luke Callahan on 02/20/2015

    Answers 1

    • Yes! I've updated the amounts.

      Posted by A Seed Growers Cooperative on 02/20/2015


Shipping Policies

We will do our best to ship out our orders within 2 business days; however, this changes to approximately 5 business days if you order seed from August through October as we are in the midst of harvest season. We ship USPS.

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Seminole-Waltham F6 Butternut Squash

Unit SizePriceDescription
3 Grams $3.50 approx. 20 seeds
1/2 Ounce $12.00 approx. 120 seeds
1 Ounce $20.00 approx. 240 seeds
1/4 Pound $50.00 approx. 960 seeds


Common Wealth Seed Growers

Louisa, VA, United States (Zone 7a)
Established in 2014
15.00 acres in production

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