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About Cultivariable
Welcome to Cultivariable! My name is William Whitson and I breed plants. Cultivariable is my business, where I sell the plants that I breed and, miraculously, mostly make a living at it. I breed plants for fun, because I am interested in discovering the possibilities. I’m not changing the world here. My discoveries are not going to feed the starving masses, save us from climate change, or expand the frontiers of science, but they might feed you if you grow them. This is mostly a one-man show, meaning that I do everything from weeding to stuffing envelopes alongside the actual breeding work.
I am an explorer of the periphery of agriculture, of both crops that never made it to common use and the more diverse but less practical traits found in commonplace crops. I don’t select new varieties because they are objective improvements on what already dominates the market. That is certainly fine if it happens, but I select varieties because I think they’re neat. If you want a great, big, round, white potato, go to the grocery store. If you want a small, oddly-shaped potato in a range of pretty colors and different flavors, you’re in the right place. If you think that you would like to breed a weird and wonderful vegetable of your own, you are also in good company, as I primarily offer genetically diverse seeds that can be used as the foundation of your own breeding projects.
My breeding work is conventional, meaning that I am not doing genetic engineering (GMOs). I don’t really have anything against genetic engineering, but it isn’t something that I could realistically do, even if I wanted to. Most of what I do is just hand pollination between chosen varieties and selection of the best resulting progeny. This is really no different than what Luther Burbank was up to more than a century ago, though perhaps better informed by the great bulk of science produced in that time.
I am mostly interested in root and tuber crops. This came about because root crops do a lot better in my climate than most things, so more of my root vegetable breeding projects survived. I also focus mostly on clonally-propagated crops. Once again, this wasn’t intentional, but these crops require a particular set of skills to manage and there is some economy in specializing in crops that share the same techniques. I mostly work with minor crops that are not commonly grown in this country and that have limitations that require breeding work to overcome. As of 2022, I am working with eleven crops: dahlia, Jerusalem artichoke, mashua, mauka, oca, potato, sea kale, skirret, ulluco, yacon, and yampah, but I spend 90% of my time on just five of them: ulluco (Ullucus tuberosus), mashua (Tropaeolum tuberosum), yacon (Smallanthus sonchifolius), oca (Oxalis tuberosa), and Andean potato (Solanum tuberosum subsp. andigenum). Those five are the crops that I enjoy the most and that reward me disproportionately with successes. You can also read about many crops in the growing guide that I no longer grow at any significant scale.
Most of what I am doing is experimental. I am not breeding varieties to be grown on large acreage. I am mostly breeding varieties for home growers and small market gardeners. Most of the crops that I work with are not particularly suited to mechanical harvest. They are typically cultivated and harvested by hand. In the field, I grow with minimal inputs because I am breeding plants and subjecting them to problems like pests and weed competition helps in selecting the most resilient varieties. Consequently, my varieties should perform well under organic conditions, as they are adapted to fairly austere conditions. My conditions are not organic though. When I do renovate and fertilize, I use inorganic fertilizer to grow and incorporate a cover crop. I use inorganic fertilizer because I need to be very careful about the introduction of diseases and I have had too many problems over the years with the introduction of organic amendments produced elsewhere. I use no pesticide and almost no herbicide. I only resort to herbicide in cases where I discover a disease that must be eliminated and I need to make sure that every plant that might communicate it is fully dead.
I grow hundreds of varieties, all in small quantities. My goal is not to supply farm-scale plantings. I serve more as a sort of private gene bank. Most of my breeding work takes place on a bit more than an acre. I have a few acres more of overflow, but that is typically more space than I need because it is only possible to pay proper attention to a certain number of plants. For me, that number appears to be about 15,000. Because my space and attention are limited, varieties come and go. If you see something you like, buy it, because it may not be back next year or ever again.
Cultivariable is located on the central coast of Washington state. The climate is dry in the summer and wet the rest of the year. We get about three times as much rain as Seattle, most of it between October and May. Because we are close to the ocean, freezes are usually short and we occasionally go the entire year without a hard frost. The temperature rarely rises above 75 F (24 C) and the warmest temperatures usually happen early in the year – in May. After that, inland heat draws in the fog and the summer tends to be cool and gray.
We have a small greenhouse and laboratory and the lab work is taking an increasing amount of my time. In the lab, I maintain varieties in tissue culture and perform pathogen testing and cleanup, which turns out to be quite important with crops that are propagated clonally. They accumulate viruses over time and require cleanup. The alternative is to preserve them in tissue culture before they are ever exposed so that you always have a clean source from which to restart. This is becoming a big part of my work, because it reduces otherwise unmanageable complexity.
That’s probably a pretty good picture. There is a lot of information on this web site, both about how the plants work and how the business does. I recommend that you take the time to read as much as you can. I try to answer questions proactively since I am often not that good at responding to them in a timely fashion.
The business has changed a lot in the past few years (writing in 2024). Sometime around 2019, powdery scab disease was introduced here (it appears to have come in through a load of compost) and that has ended my ability to sell tubers grown in the field, so I now focus on selling seeds instead. I do sell some pot grown tubers and also in vitro plantlets, but these methods don’t scale well, so tubers and live plants make up a much smaller part of the business than they used to. Then, in 2022, a freeze and power outage damaged my in vitro plant collection, which resulted in the loss of many varieties, including many of the old standards. The result is that I have spent a lot of the past few years, rebuilding, changing how I work, and breeding new varieties to fill the holes made by what was lost. This was a difficult time, but I have worked through it and, in 2025, I will be back to full scale operation again, which is exciting!
It is my great privilege to create things that other people enjoy and to share what I have learned along the way. Thanks for visiting!
Glad I found your website. I’ve been looking for a good source of these tuber for awhile.
Thanks’
John
I received the ulluco, mashua and oca tubers and some potato seed from you folks, and I have to say that I’m glad I found you! :-) Many of the tubers were already forming buds when I got them, so I must have just got in under the wire with my order. :-p Pity I missed out on the yacon and the grab-bag of ulluco- somebody snagged the last of those before I could, the lucky dog.
I’m looking forward to growing these veggies in my attempt at a self-sufficiency garden. I’m hoping the massive storm that sat and blew the heck out of us for the last four days won’t ruin my tubers’ chances. (crosses fingers)
Thanks again for providing these rarities!
TD, thanks for letting us know that everything arrived safely. Check in around November for anything you missed. We are going to have at least three times as many varieties for next year and we are growing a lot more yacon to meet demand. We tend to send sprouting tubers to locations that are already suitable for planting. That doesn’t mean that you have to plant right away though. You could easily go another month before planting or you can pot them up to grow a little bit before transplanting them. I think your storm can only help. All of these crops like plenty of water. Good luck!
Have grown this special tuber x 24 years; my Anna hummers love the bright flowers each fall. Lost all (hundreds) of my tubers last winter. Reordered 3 (sad-looking nonviable ones) from another well known company. Sadly never grew. Hoping to give the birds their gourmet treat this fall if possible. A Seattle Urban Farmer
Highly instructive website. Thanks for posting the comprehensive information on growing and storing yacon.
Thanks Kezza – that’s always nice to hear!
Glad to find this amazing project. I was so impressed with the excess dahlia “tubers” after thinning, and just wanted to know if they were edible. I appreciate the detailed information on so many different uncommon edible plants!
Will you please give some justification for being anti-GMO? As far as I’ve been able to tell, it’s along the same lines as believing in the flat earth or that vaccinations cause autism. Given the quality of the growing guides and blog posts I’ve seen here, I really don’t want to believe that you people could be so anti-science.
I’m not anti-GMO. I’m not exactly pro-GMO either. Saying that our work is non-GMO is not an ideological statement, just a factual one. I get a surprisingly large amount of email asking which of our products are genetically modified or making assumptions that they must be, so it saves some time for me to broadcast the very straightforward answer that all of my breeding is conventional. Philosophically, I occupy the ideologically impure middle ground. I am in favor of genetic engineering as a plant breeding tool. I am also generally unimpressed with most of what has been accomplished with it so far. I don’t expect that situation to continue indefinitely though. We will learn by using the technology as with any other and I expect the applications to get better as we learn. If it were within my capabilities, I would definitely investigate GE to solve certain kinds of problems, like photoperiod or male sterility, for example. It is not a real temptation for me because GE is just not practical on my scale. If it ever comes within my reach, then it will be an interesting negotiation with our customers to discover what they would be willing to accept.
One reason many people are skeptical about GMO crops is in many instances the process involves introducing DNA into plants from other plants that naturally would never be possible. This theoretically could lead to complications that could affect the entire environment. Some of these experiments are being done in an open environment where as to be on the safe side should be done in sealed labs. As much as the industry wants to downplay these risks, they don’t know and could be playing with fire
Sir Whitson,
I am a native farmer from Wendake, Quebec province in Canada (the reserve is in Quebec city). My language is French, English is my second. I have a project with yacon. From my reserches in Canada, USA, Peru I discover your site. It has many information than I could not find any where. I would like to know if you are agree to discuss with you by e-mail or skype about my project. As, I would like to know witch kind of variety my yacons are, and how far North parallele they can be cultivated.
Sincerely Johanne Paquet Sioui
Sure, just send me an email at help@cultivariable.com. To identify yacon, I need pictures of the leaves stems, storage roots, rhizome, and the flower if possible.
Kia ora from New Zealand! Do you have any tarwi seeds available at the moment? Thanks, Amber
Not this year. Hopefully I will have a fresh batch next year.
I just found your website and will enjoy your podcasts later. What do you know about Apios americana (ground nut). I can’t put a spade in my ground without hitting a tuber of it. I wonder if you know of anyone developing a larger-sized tuber. Mine never seem to be greater than an inch or so in diameter.
You can read more about groundnut in our growing guide. There are larger varieties and Louisiana State University ran a breeding program for several years that produced a number of improved types.
Hello William! I’m very pleased to have come across your blog (linked form Permies.org). Your project sounds very impressive: the dedication, curiosity, meticulousness and creativity. Wishing you all the best from southern Mexico!
Thanks Linda!
Went on a search to find out what the green berries were on my potatoes and found your wonderful site! Thanks for all the great info and your kind and thoughtful answers to all questions posed to you.
Thank you for your article about hopniss! It’s one of my favorite tubers, but I made the mistake (on my 3rd or 4th time eating it) of using it in a quick hashbrown and the results were enough to keep me from trying it again for a long time. I haven’t found many people who write about this aspect of the plant, and I was glad to find someone with a similar experience. Like you, I have returned to the hopniss fold, but I now cook my tubers much longer. Since moving to NM, I haven’t been able to forage for them, although I do collect some when I get back east. I’m going to go through your site now to see if I can order some to grow here, with irrigation, of course!
I am so happy I found your site! I have been growing fruit, herbs, and edible flowers for myself and for fun. I learned from you that there are dahlias which grow potatoes. I am growing a Amorphophallus titanum (corpse flower) just to see if I can get it to bloom and it has edible tubers. There are other breeds that don’t take as long as this one. Now I’ll grow edible dahlias! I’m very happy you exist and hope you have many more years of selling to us. I enjoyed reading my first newsletter from you and look forward to more.
Hi William,
‘Thankfully I bought your seakale thongs a few years ago, before the international embargo!
The seakales are doing well, and I split one into 5 sections to share – they seem to be doing well.
I kept 2 and the others went to a group growing flowering plants to support their urban bee hive and heard that sea kale was recommended.
I was looking for Oca (Oxalis tuberosa) but I guess it’s not possible to get up here to BC.
BTW – just finished a green salad with crunchy dahlias. We grow white Carl Chilson dahlias up here at the heirloom wilderness gardens at Cougar Annie’s Garden and enjoy the surplus tubers for salad. Tastes are like sun chokes. The rest will be made into kimchi!
Enjoy your website – keep up the good work!
Makiko
I am so glad I found your website!! I spend summers in Belfast, Maine (central part on the coast) and winters in Rocky Mount, NC. My husband and I are curious about being able to grow maca in one or both locations…? We transport the farm and garden back and forth, and I’m thinking if the maca was kept in a small greenhouse situation by itself it might be ok…?
Would love your advice!
In ME, the problem will be cold, as maca needs a long growing season without any hard freezes. NC gets warmer than maca likes, particularly in a greenhouse, so you would probably want to grow in pots and move them in and out. If you are willing to put in the extra effort to keep the plants happy, you can probably pull it off.
Hafa adai from Guam, zip code 96915. I would like to pre/order and try your yacon varieties. I have gotten a yacon “sett” from another source which unfortunately rotted. Will you ship directly to Guam?
Hi Frank. It is hard to tell for sure, but I don’t think that Guam allows vegetative material from the mainland USA. You may be able to get a better answer locally than I was able to find on the Internet.
Is it possible to visit your farm? We are located a bit south of Tillamook, OR and plan a trip to Olympic National Park sometime soonish. So it seems reasonable that conceivably we could stop by if that was agreeable. This is a lot of ‘iffyness’, isn’t it?
For a variety of reasons, we can’t accommodate visitors. Maybe at some point in the future as I move more things to our second plot, but definitely not this year. Thanks!
Will you be getting the Lumper back in stock?
It will be back again this fall, after harvest.
I found your site because I was looking for potato onion info and then was totally captivated by the site. Soooo many foods I had never heard of :) . During the last couple of years I have found it harder and harder to purchase decent potatoes – often they are greening – not long ago threw out a whole 10 lbs worth of green potatoes fresh from the store.
I have never made a serious attempt at growing my own, because I’m unable to purchase seed tubers locally and on-line vendors will not ship early enough for my zone 8. So, I am giving the TPS tetraploids a chance :). Btw, should you know of anyone who sells day-neutral potato onions, I would love to hear from you. Thanks !
Hi Elizabeth. TPS is certainly a good option if you find it hard to get quality seed potatoes at the right time and ware potatoes carry a lot more risk of disease than those intended for use as seed. I may have some day neutral potato onion seed in the future. A couple of the varieties that I am evaluating seem to bulb at unusual times.
do you do phyto sanitary certificate and do you have any yacon seeds?
I don’t offer phyto certs. Yacon seeds, if any, will be available around December.
I am so excited to try to plant potatoes from true seed. I received my seeds thank you. My only concern Is will these potatoes cross pollinate with Silverleaf nightshade. I live in Texas and they are all over the place in my pastor and the yard. Hopefully they won’t I hope I just figured I better ask just incase.
Hi Melissa. There should be no worries of crossing with any native Texas Solanaceae. Potatoes are only able to cross with other members of the potato family. Happy growing!