Locally Adapting Pumpkins


The perennial plant breeder Wes Jackson once said, “If your life’s work can be accomplished in your lifetime, you’re not thinking big enough.” The joy of working on something that is bigger than you and which connects you to the web of life is shared by all plant breeders. Being linked to the reproductive cycles in your ecology through the application of consciousness, vision and hard work is truly rewarding. It takes being attuned to the changing conditions in your environment and applying imagination for how the world could become, before acting mindfully to bring it about. 

I was inspired by the link between plant breeding, food and ecology from an episode of Chef´s Table that profiled the ethical and sustainable food philosophy of chef Dan Barber. His vision is of chefs and plant breeders as keystone species in our ecology who steward adapting cultivars while creating more beautiful interactions between people and what they eat. This includes taking the entire farm and its ecology into mind, including regenerating the soil which is the cornerstone of great tasting and nutrient dense food.

Dan had worked with plant breeder Michael Mazourek of Cornell University who bred the famous Honeynut pumpkin.  Honeynut is not only a hybrid between two varieties of one species, but also a stable de-hybridized cross between two different species: Buttercup C. maxima and Butternut C. mustachata

The idea of de-hybridization was something I was inspired to try when I read Carol Deppe´s book Breed Your Own Vegetable Varieties. To de-hybridize simply means continuing to grow out generation after generation of the material one is working on, while selecting out any undesirable traits. Once the next generation is more or less identical to the last, you have achieved an “open pollinated” variety and the de-hybridization process is done. This is also where I got the idea to start work on breeding my own pumpkins. She made it seem quite easy despite being a process that would clearly take several years to complete but would result in a new locally adapted cultivar.  

I grew about 50 varieties of pumpkins for the first few years in search for the right varieties from which I might eventually breed my own locally adapted variety. I trailed varieties of all the five main domesticated species: Cucurbita pepo (Spaghetti squash, Mandan, Zucchini and hulless seeded varieties), C. maxima (Hubbard, Buttercup, and winter squashes), C. agryosperma formerly called mixta (Apache Giant, Navajo cushaw) and C. moschata (Musquee de province, Butternut). The fifth C. ficifolia I have largely ignored, although it has sent me in the direction of the Gourd tribe which is within the greater Cucurbitaceae Family of which Cucuzzi Gourd (Lagenaria siceraria) is my favorite. 

The most popular and diverse species is C. pepo and I focused my first real seed saving project on the pepo variety of Mandan Squash. Through many trials I realized that the good tasting squash was in the maxima and moschata species. Moschata tend to take more time and need more heat as they are from further south in the Americas. I therefore abandoned most varieties of moschata except those that are quicker to mature like Butternut and Honeynut. 

I ended up contacting Michael Mazourek and asked him for advice about what I should use as the father and mother for my new breed. I knew that, like Michael, I would use Buttercup genes for one half of the mix due not only to its superior taste, but also because it’s a short season variety. Buttercup was discovered as a chance seedling in 1925 by the North Dakota State University Agricultural Experiment Station. As it was bred to grow in the Northern Great Plains, it is well suited to the Nordic climate where I farm.

Michael advised against crossing two species as he did with Honeynut. Instead, he suggested finding a smaller short-seasoned bush variety as the other parent, but one that is also C. maxima and will thus cross without artificial breeding. 

This autumn is the first time I have seen the results of last year’s crosses. They look great and have a lovely mix of expressions of both parents in them. I grew them out alongside more of the parent varieties. I did this for two reasons: firstly, because I was not sure how the cross would look or work, and secondly, because I wanted to add waves to the mix of first-generation crosses “F1” and second-generation crosses “F2”. This fits into one of the principles of doing things in waves instead of straight lines like most productive agricultural practice (read more about waves in my blog article Ecological Bottlenecks ). The hybrid vigor along with great conditions this year have given the best outdoor results I have seen. We now have 30-meter rows which have spread out 10 meters wide, engulfing several rows of alliums and other vegetables.

I am excited to think about how this project will evolve. For now, I am simply happy to be seeing great results, which has not always been the case in previous projects. It takes a lot of failing, time, and devotion to create something new that will last. Being stewards of our ecological inheritance is not just about taking care of rare heirlooms, but also creating heirlooms for the future that are in constant co-evolution and adaptation to the rapidly changing climate. I hope stories like these inspire more people to connect to their ecology in active positive ways. There are far too few keystones these days, but the potential is for all of us to be just that.    


  1. Interesting and important work, thanks for sharing!

    Out of curiosity, which was the second parent you decided to use for your cross?

    Would be fun to try something similar here in the south of Sweden.

    1. Thanks Christopher. I keep the second half a secret so people dont start stealing my work by registering it as their own cross. I am happy to send you seeds of my cross and you can help me do the de-hybridization work if you like. My work stays with the OSSI-Open Source Seed Initiative and should not be patented.

    1. No, I had not heard of Joseph Lofthouse. Thanks for cluing me in. Ill be sure to look into his work.

  2. Great article, thanks! I’ve been crossing quite a few squashes here in Belgium. Sometimes, bees and bumblebees give surprise crosses, too, even between species.

  3. Makes sense to protect against , such a strange place we’re in, where we can patent the genetics of a plant.

    I’ll happily give that try, thanks for the offer, I’ll send you a private message.

    All the best,

    1. Thanks Christopher. Ill share seeds with you if you share your experiences of growing them with me and try to keep reproducing them.

Leave a Reply

Your email address will not be published.

ten + ten =