How to Tell When a Chestnut Is Ripe

Sweet chestnuts (Castanea spp.) grow throughout much of the United States. North America originally had its own chestnut species (Castanea dentata), but a blight epidemic managed to destroy nearly all of them. European and Asian chestnut trees (Castanea sativa, mollissima and crenata) have thrived in C. dentata’s place and are suitable for home growing if you have enough room. The edible part of the chestnut grows inside a burr, which opens once the nuts are ripe.

Thick work gloves

Clippers

Long pruning pole

Put on thick work gloves. Chestnut burrs look fuzzy from a distance, but they are actually covered in little spines.

Gather all fallen burrs under the tree that are open. This is a basic sign of ripening. Most regions see chestnuts ripen in September or October over a few weeks; contact the agricultural extension office in your county for average times.

Inspect the nuts inside the opened burr for color, firmness and fullness. Ripe nuts should be dark brown and full. Discard any with wrinkles or that seem otherwise rotten. If you see a greenish color, the chestnut is unripe, and the burr has opened and fallen prematurely; the University of Florida notes that these should ripen within a few days, although the BBC advises that pale chestnuts can shrivel up instead. Store fallen unripe burrs in a cool place.

Pick opened burrs off the tree if the nuts inside appear to be healthy, brown and plump. While the typical sign of ripening for chestnuts is the moment they fall from the tree, the American Chestnut Cooperators Foundation points out burrs can open on the tree but not fall, even though the nuts are already ripe. Clippers and, if the tree is very tall, a long pruning pole, are the Foundation’s suggested tools.