Chinese Chestnut

Site and soil

Chestnuts are particular about one thing, and that is drainage. They want deep, well-drained, acidic soil at a pH of about 5.5 to 6.5, and they will not tolerate a saturated root zone, which rules out bottomland and heavy wet clay. A well-drained hillside with a sandy loam or loam is ideal. Full sun, eight hours or more, is required for a crop.

Chestnuts are frost-sensitive in spring when the new leaves are out, so plant toward the top of a slope where cold air drains away rather than in a hollow where it settles. Water needs are moderate, and an established tree handles ordinary summer dry spells, but the nuts size up in late summer and a deep soak during an August drought makes a real difference to the crop.

Spacing

Plan for a tree 40 to 60 ft tall and about as wide, with a broad, rounded crown. Set trees 30 to 40 ft apart. Orchards plant closer and thin later, but for a food forest give them their room from the start. Keep pollination partners within about 100 ft of each other; closer is better.

Planting

Plant in spring before bud break. Chestnuts put down a taproot early, so choose the permanent spot the first time.

• Dig the hole as deep as the root system and twice as wide, with the sides loosened.
• Set the tree with the root flare level with the surrounding ground.
• Backfill with the native soil, without fertilizer, and water in well.
• Mulch 3 to 4 inches deep from near the trunk to the dripline, pulled back a hand's width from the bark.
• Guard the trunk. Deer browse young chestnuts hard, and voles girdle them under snow. A tree tube or wire cage for the first three or four years is the difference between a tree and a stub.

Pollination

Chestnuts cannot pollinate themselves. The long, creamy catkins open in June with a strong scent that draws beetles, flies and bees, and pollen also moves on the wind, but a tree needs pollen from a different, unrelated chestnut to set nuts. Plant two or more, and three is safer than two since seedlings vary in bloom time. Any Chinese, hybrid or American chestnut nearby will serve as a partner.

First-year care

• Water deeply once a week through the first growing season and during dry spells the second.
• Keep the mulched circle free of grass and weeds out to the dripline.
• No fertilizer in year one. Chestnuts are sensitive to fertilizer burn when young.
• Check the tree guard each fall before deer rut and each spring after snowmelt.

Pruning

Train a young chestnut to a single central leader by removing competing uprights in the first few winters. After that it needs little: take out dead, broken and crossing limbs while dormant, and raise the lowest branches gradually over several years if you need to mow or walk underneath. Keep cuts small on a young tree; it needs its leaves.

Harvest

Seedling trees begin bearing in about 4 to 7 years, with crops increasing for decades. The spiny burs open around the first frosts in September and October and drop two or three glossy brown nuts each. Gather every day or two while they are falling, because deer, turkeys and squirrels work the ground under a chestnut as hard as you do. Wear gloves and use a rake or a rolling nut gatherer; the burs are sharp.

Fresh chestnuts are more like a vegetable than a nut and will mold or dry out if handled like walnuts. Float the nuts in water and discard the ones that float. Store them in a ventilated bag in the refrigerator, where they keep about a month and sweeten as some of their starch turns to sugar, or freeze them for a year or more. Score the shell before roasting or boiling so they do not burst. A mature tree gives 50 to 100 pounds.