Know what you’re picking. Many ferns have fiddleheads, but the ones we eat in Maine are from the ostrich fern. Ostrich ferns tend to grow near streams and rivers and have three good identifying characteristics: They have a smooth, green stem; they have a deep, u-shaped groove on the inside of the stem, and they will have a brown, papery covering when just emerging from the crown.

Know when to pick. Fiddleheads emerge in the spring from perennial crowns. The season for picking is short — about two weeks in a given area. Fiddleheads will be up as the forsythia and serviceberry bloom.

Get permission to pick. Ask the landowner’s permission to harvest first. Town offices can supply landowner names from maps if you are not sure who owns fiddlehead grounds.

Don’t over-harvest. University of Maine research shows that picking more than one half of the fiddleheads from a crown will reduce plant vigor or kill the plant. Don’t harvest from crowns having fewer than four fiddleheads or if the fiddleheads are smaller than a quarter.

Cook them properly. Steam for 10-12 minutes (and don’t pack them in too tightly), or boil fully covered fiddleheads for 15 minutes from the boiling point. Symptoms of foodborne illness have been noted when cooking for shorter times.

David Fuller works for the University of Maine Cooperative Extension. The University of Maine at Farmington will hold its fourth annual Maine Fiddlehead Festival on Saturday, May 2, outdoors at the Emery Community Arts Center. At 10 a.m., Fuller will teach you about the lore and science of ostrich fern fiddleheads and then walk to a nearby spot to talk about identification and sustainable harvest. The session will last 1 ½ hours. Be prepared to walk on muddy ground.