Black Futsu Squash: Growing the Rare Japanese Heirloom in Kansas
By Autumn Prairie Pumpkins
Black Futsu is one of those varieties that stops people in their tracks. The skin is dark, nearly black when immature, covered with rough, warty bumps that look more like a toad than a squash. As it matures and cures, it shifts to a deep chestnut brown with a rustic, almost prehistoric look. It's the most visually striking squash in our entire collection, and the flavor more than backs it up.
This is a traditional Japanese heirloom from the Cucurbita moschata family. In Japan, small pumpkins and squash like Black Futsu are prized for individual serving sizes and intense, concentrated flavor. It's been grown there for generations, and it's perfectly adapted to hot, humid summers, which means it transitions to Kansas gardens without breaking a sweat. And being moschata, it's naturally resistant to the squash vine borers that plague Midwest gardens.
Why Black Futsu Deserves a Spot in Your Kansas Garden
Beyond the obvious beauty factor, Black Futsu has several practical advantages. The fruits are small, typically 3–5 lbs, which means they mature faster than larger moschata types. Days to maturity run 90–105 days, giving you a comfortable margin in Zone 6b. The compact fruit size also makes them easy to handle, store, and cook as individual servings.
The moschata vine borer resistance is the headline feature for Kansas. While pepo squash are collapsing by July, Black Futsu's thick, corky stems keep the vines productive through the worst borer months. Powdery mildew resistance is also better than average for winter squash.
For Kansas-specific growing guidance, K-State's squash vine borer guide (MF3309) covers general cultivation practices that apply directly to Black Futsu.
How to Grow Black Futsu in Kansas (Zone 6b)
Starting Seeds
Direct sow after last frost when soil hits 65°F, mid-May in central Kansas. Plant 1 inch deep, 2–3 seeds per hill, thin to strongest plant. Indoor starts work well too, 3–4 weeks before transplant date in 3-inch pots. Black Futsu germinates reliably in 7–10 days with warm soil.
Spacing
Space plants 4–6 feet apart. Black Futsu vines are moderately vigorous, not as rampant as Seminole or Dickinson, but they still need room to breathe. Good airflow between plants reduces disease pressure, which is always worth the extra space.
Soil and Fertility
Well-drained soil with compost worked in. pH 6.0–6.8. Moderate feeder, apply balanced fertilizer at planting and side-dress once when vines run. Don't over-fertilize with nitrogen or you'll get massive vines and delayed fruiting.
Watering
1–1.5 inches per week through fruit set. Drip irrigation keeps foliage dry and reduces mildew risk. The smaller fruit size means Black Futsu doesn't need quite as much water as the large-fruited varieties.
Harvest and Cure
The skin transitions from dark black-green to deep chestnut brown at maturity. The bumpy texture becomes more pronounced. Harvest when the stem is dry and corky. Cut with 2–3 inches of stem. Cure for 2–3 weeks in a warm, dry area. Black Futsu is an outstanding storage squash, properly cured, it stores 6–8 months. The flavor intensifies significantly with storage time.
Black Futsu in the Kitchen
Cut in half, roast at 400°F cut-side down for 30–40 minutes. The flesh is golden-orange, dense, dry, and intensely sweet with a pronounced nutty flavor, somewhere between chestnut and sweet potato. The small size makes each fruit a perfect individual serving.
In Japan, similar small squash are simmered in dashi broth (nimono style) or tempura-fried. Black Futsu is also excellent cubed and roasted for grain bowls, pureed into soup, or simply halved and served with butter and a drizzle of maple syrup. The thin skin is edible after roasting, which makes prep even easier.
Saving Seeds
Black Futsu is open-pollinated. Save seeds from fully mature, well-cured fruits, scoop, rinse, dry 2–3 weeks. Stores 4–6 years. Will cross with other Cucurbita moschata varieties. Isolate by 500+ feet or hand-pollinate for pure seed.
Add Something Rare to Your Garden
Black Futsu Squash Seeds ship from Newton, Kansas. See our full collection of rare heirloom squash and pumpkin seeds.
More growing guides: Shishigatani Squash Growing Guide · Thai Kang Kob Pumpkin Growing Guide · Wan Fu F1 Pumpkin Growing Guide