A Seed Breeder’s Journey to Turtle Moon Blue Kuri
Twenty-seven years ago, Tom Vigue of Sidney, ME, grew Green Hokkaido kabocha squash—which Fedco then carried—alongside a buttercup in his garden. The following fall when he was cleaning out his pantry to make room for the new squash harvest, he was surprised to find a year-old Green Hokkaido that still looked solid. He scooped out the seeds and cooked it up to discover it was as good as any kabocha he had eaten from that year’s harvest. He set the seeds aside and planted them the next year, 1997.
For twenty years he continued saving and replanting seed from the best fruits, but he did not isolate the plants from other squash in his patch—over that time, what would eventually be called Turtle Moon cross-pollinated with no less than 15 different Cucurbita maxima varieties.
Five years ago, after numerous dinner guests praised the squash, Tom started to grow it in isolation by giving the seed to neighbors to plant in their gardens. At that point there were half a dozen shapes and sizes, along with varying seed types in the mix, so he started carefully selecting for kabocha shape and seed type, and of course for good flavor.
Two years ago, after famed seedsman Will Bonsall told him, “You’re never going to get this done unless you go out there and be your own bee,” Tom started pollinating the flowers by hand.
Turtle Moon Blue Kuri is the result of all those years of observation and work. As Tom opines, “It has lots of vigor from all those varieties crossed in, and has become very adapted to this part of the world over these past twenty years.” It’s this kind of work that will adapt us to the next twenty years.
About 160 seeds/oz. ⅛ oz packet sows 4 hills.
Kabocha is a Japanese “pumpkin.” Kabochas look like buttercups without the protruding cup on the blossom end.
Green in stems signifies immature fruit. Fat round stems turn corky and woody when the squash is ripe. Fruits tend to be medium to large and often have bumpy surfaces and button-ends. See also large pumpkins: Lumina, Rouge Vif d’Etampes and Big Max.
Culture: May be direct-seeded or transplanted. Minimum germination temperature 60°, optimal temperature range 70–90°. Direct seeding: Sow 4–5 seeds per hill when weather has warmed after danger of frost. Allow 4–6' between hills. Thin to 3 best plants. Transplanting: Start indoors three weeks before setting out. Do not disturb the roots. Transplant bush varieties 18" apart, vining varieties 30" apart. For either method, use wire hoops and row covers to hasten maturity and reduce insect damage. Tender, not frost hardy. Heavy nitrogen feeders. Excessive heat and/or drought can prevent blossom set, reduce yields. Winter squash can take one or two light frosts on the vine. To improve flavor and storage, field cure for at least 10 days after harvest, covering if hard frost threatens. Store under proper conditions, at least 50° and 60–70% relative humidity in a place with good air circulation. Do not pile up squash. Inspect periodically and be sure to use damaged, stemless or small fruit first. Acorns have the shortest storage time before getting stringy, followed by delicatas, buttercup/kabochas.
Saving Seed: Saving squash seed is challenging! We list three species of the genus Cucurbita: C. pepo, C. maxima and C. moschata. Varieties of the same species will cross readily, but crossing will not occur between the different species. You must isolate varieties of the same species by half a mile if you want true-to-type seed. This is difficult for most gardeners—you may have to communicate and collaborate with neighboring gardeners, or exclude insects from blossoms and hand-pollinate. If you can pull off the variety isolation, processing the seeds is easy: rinse seeds from the guts of fully ripe and cured squash. Dry and store.
Diseases: BR: Black Rot, PM: Powdery Mildew
Pest: Striped Cucumber Beetle
Cultural controls: use tolerant or resistant varieties, rotate crops, till under crop debris soon after harvest, use floating row covers until flowers appear, use plastic mulch, perimeter trap cropping (Black Zucchini and Blue Hubbard make particularly good trap crops), use yellow sticky strips, hand-pick early morning when beetles are very sluggish.
Materials: Surround, Pyrethrum (PyGanic).
Pest: Squash Bug
Cultural controls: rotation, till in cucurbit debris before winter and plant a cover crop, boards on soil surface near squash will attract bugs overnight which can be killed, avoid mulching. Squash bugs lay their brown-brick red egg clusters on the underside of the foliage, often next to the central vein—destroy egg clusters on undersides of leaves.
Materials: Pyrethrum on young nymphs, AzaMax.
Pest: Squash Vine Borer
Cultural controls: butternut squash is resistant, maximas & pepos susceptible; rotation, plow in squash vine debris soon after harvest, use floating row covers, watch for wilting plant parts and destroy borer within.
Disease: Powdery Mildew
Controls: Use small plots to slow spread, plant indeterminate (viney) varieties, control weed competition.
Materials: sulfur and whole milk, mineral or other oils in combination with potassium bicarbonate.
Disease: Bacterial Wilt
Cultural control: Striped Cucumber Beetle is vector—control it; choose resistant varieties.
For the latest results of our germination tests, please see the germination page.