By land and by sea, Dorchester residents are expected to be out in great numbers this year celebrating the scariest of holidays, Halloween. From a scarecrow contest to floating pumpkins and costume parties, local organizations have something planned for revelers of all ages.

Cedar Grove Gardens is holding its annual scarecrow contest and several entries are already on display at the 911 Adams Street store. Individuals and groups are invited to drop off their creations, which will be displayed outside the store until Oct. 25. Customers can vote for their favorite entry, choosing one for individual and one for a group entry, from now through Oct. 24.

Entrants are encouraged to bring their scarecrows to Cedar Grove as soon as possible, with the name of the scarecrow and contact information for the artist. The winners will be announced at a festival planned for 1 p.m. to 3 p.m. on Oct. 25. First prize will be $100, second prize $50, and third prize $25.

The festival will also feature a parade, free balloons and refreshments, and hayrides through Cedar Grove Cemetery. Children will also have the opportunity to smash a pinata full of candy. For more information, contact Cedar Grove Gardens at 617-825-8582.

The Great Pumpkin Float

An eerie sight will fill the waters running from Davenport Creek out to the Neponset River on Oct. 25 when the Boston Natural Areas Network hosts its 8th annual Great Pumpkin Float at 5:30 p.m. at Pope John Paul II Park. Participants are invited to bring a 6-inch to 8-inch pumpkin that has already been carved out at home. Each jack-o-lantern will have a candle inserted and lit and will be launched into the water on a styrofoam float.

The event is free, but families are asked to register by giving their names, numbers of children and numbers of pumpkins to the BNAN at 617-542-7696 or via e-mail to info@bostonnatural.org.

The BNAN was organized in 1977 to preserve, expand and improve open spaces in urban areas. “Usually there are about 200 pumpkins and about 500 to 600 people who come to watch,” said Candice Cook, program manager at the BNAN. “Lots of kids wear costumes.”We get calls starting in the summer seeking more information about the event,” said Cook.

The direction of the floats depends on the tide. According to this year’s tidal chart, these illuminated pumpkins will be floating out to the Neponset River toward the harbor. The organization allows the pumpkins to float just under one quarter of a mile before they are corraled by ropes across the river. Once collected by volunteers in canoes, the pumpkins are taken to a compost pile at the BNAN’s City Natives nursery in Mattapan. The floats are recycled to be used again next year, Cook said. The rain date for the event is Oct. 26.

The Dotini Party – Fields Corner Main Street is hosting the 5th annual Dotini Party fundraiser on Oct. 29 at 7 p.m. at the Blarney Stone, 1505 Dorchester Ave. The event features food, music and a costume contest and will introduce the “Halloween-Tini.” Tickets are $35 at the door and $30 in advance. For more information, call 617-474-1432 or look on the web at fieldscorner.org.

Monster Mash – The Dorchester YMCA Monster Mash will be held on Oct. 30, from 6 p.m. to 8 p.m. at the Y at 776 Washington Street. Participants are encouraged to wear a costume. The event will include games and candy. There will also be a Pumpkin Decorating Contest, held in collaboration with the Brothers of the Delta Phi Upsilon Fraternity Inc. For more information, call 617-436-7750 or look on the web at ymcaboston.org/Dorchester.

DotArt Course – On Halloween itself, DotArt will be launching the first session of “Wearable Art,” a nine-week course that will be taught by the artist Carol Price. “Her first class will have a Halloween theme,” said Rebecca Dicks, director of administration at DotArt. The course will include a variety of projects including jewelry, bags and perhaps making costumes, Dicks said. For more information or to register, participants may call 617-265-3503, visit dotart.org, or stop by the office at 18 Samoset St. Courses are held at the studio, which is located at 1782 Dorchester Ave.