Sixteen architecture firm offices are open to the public on Saturday, 11 a.m.-4 p.m., for Don't Tear It Down's First Annual Architects Tour. The offices of Arthur Cotton Moore, Hugh Newell Jacobsen, Hartman/Cox, Anderson Notter, Mariani and Keyes, Condon & Florance are among those opening their doors. Two architecture studios for undergraduate students will also be open. Many of the architects will be present to talk with visitors, according to tour coordinator Karen Shook. Following the tour, a reception will be held at the International Institute of Design, 2225 R St. NW between 3 and 5 p.m. Tickets are $8. Call 737-1519.

IKEBANA

The "Arts and Flowers Show" will open Thursday at the Art League Gallery in the Torpedo Factory, 101 N. Union St. in Alexandria. The show will continue till Monday, Oct. 5 and can be seen between 10 a.m. and 5 p.m. The floral arrangements or ikebana are by members of the Washington chapter of Ikebana International, which is celebrating its 25th anniversary. Besides the flowers, crafts by many Torpedo Factory artists will e shown. Call 836-8564.

In conjunction with the Arts and Flower show, Alexandria's George Washington Bicentennial Center, 201 S. Washington St., will hold an Autumn-Moon Viewing Festival starting Thursday and running till Monday. An autumn-moon viewing festival is a traditional Japanese observance--autumn flowers are arranged for an offering made to the autumn moon. The festival includes ikebana and brush painting demonstrations plus lectures on kimonos, the Japanese tea ceremony and the koto--an 18-stringed Japanese harp that is played horizontally. Call 838-4994.

The Center also begins its Brown Bag Lunch lecture series Friday, 12:30-1:30, with a talk and demonstration of ikebana. Free. Future lectures on topics including antique furniture buying will be held each Friday through Nov. 20. Call 838-4994.

LECTURES & TOURS

The 38th annual Waterford Homes Tour and Craft Exhibit will take place next Friday-Sunday, 10 a.m.-5 p.m. Ten homes in this restored 18th-century Quaker village will be open. Crafts demonstrations ranging from weaving and dying to lace making and candle making, will also be held. Call (703) 882-3018.

Curator Katrina Taylor of the Hillwood Museum, 4155 Linnean Ave. NW, will offer a four-week lecture on Russian art at Hillwood Oct. 6-27, noon-1:30 p.m. or 6-7:30 p.m. Fee: $30. Call 686-0410 for reservations.

Doorways to Old Virginia will sponsor a tour to 18th-century New Castle, Del., on Oct. 7. The tour includes a visit to the George Read II House and the Amstel House, as well as lunch at the New Castle Inn. The bus departs from Christ Church, 100 N. Columbus St., Alexandria. Fee: $40. Payment due Sept. 30. Call 548-0100.

The 17th annual Historic Arlington Day Tour, sponsored by the Arlington Historical Society, will take place Saturday, noon-5 p.m. Tickets for the day tour are $5 for adults and $2 for students. Call 243-7946. A candlelight tour of Arlington House will be held Friday between 7:30-9:30 p.m. Tickets for the evening tour, sponsored by the National Park Service, are available by calling 557-0613.

CARPETS

"American Hooking: A Connecticut Tradition" will open at the Textile Museum Shop, 2320 S St. NW Friday. The show, which runs till Oct. 31, focuses on the work of Trudi Shippenberg, a contemporary fiber artist who works wool and other assorted materials into vibrantly colored, textured panels.

On Saturday at the Textile Museum, conservator Clarissa Palmai and Harold Keshishian will hold a potpourri session on carpets, 10:30 a.m. Call 667-0441.

CERAMICS

Jeff Kirk will show his recent ceramic vessels starting Friday at Glen Echo Gallery, off MacArthur Blvd. in Glen Echo, Md. Kirk uses primitive firing techiniques including sawdust, pit and dung-firing. Open: Monday-Thursday, 10 a.m.-5 p.m.; Saturday and Sunday, noon-6 p.m. Call 492-6282.

Translucent porcelain pots and raku ware by Jean Hay is on exhibit at Grey House potters, 5509 Wilson Blvd. in Arlington. Hours: Monday-Friday, 10 a.m.-6 p.m.; Saturday, 10 a.m.-5 p.m. Call 522-7738.

COMBINATION SHOWS

Gallery 324, 324 N. Fairfax St. in Alexandria will open "Earth, Wind and Fire" -- a show of potters and fiber artists -- starting Tuesday. The show includes the work of potters Lois Dowell, Ileen Shefferman and Gail Spane as well as the fiber work of Daphne Malcolm and Joan Griffin. Works by other gallery members will also be displayed. Hours: Tuesday-Saturday, 11 a.m.-5 p.m.; Sunday, noon-5 p.m. Call 548-ARTS.

Ceramics, fiber works, stained glass, prints, sculpture, paintings and photographs are on display now through Oct. 11 at the Greater Reston Arts Center (GRACE), 11400 Washington Plaza West in Reston, Va. Entitled the Annual Artists/Designers Exhibition, the show includes the work of 24 artists/designers. Hours: Tuesday-Saturday, 10 a.m.-5 p.m.; Sunday, noon-5 p.m. Call 471-9242 or 437-0776.

GRACE will hold its fifth annual "Art for Gifts" show beginning Nov. 13. Artists in the following crafts are invited to submit their work: ceramics, fiber, glass, jewelry, baskets, toys and especially prints. Works should be brought to GRACE on Oct. 4 or Oct. 11, noon-5 p.m. to be evaluated by the GRACE staff.

Zenith Gallery, 1441 Rhode Island Ave. NW (to the rear), is showing works by five female artists now through Oct. 10. The show includes Ansley Wallace's hand-dyed silk ties based on rubbings of architectural ornamentation; Betsy Stewart's collages of reassembled acrylic abstract paintings; Linn Westbay Woloshin's sculpture in stone and cast bronze; Mary McCoy's abstract mixed media on paper; and Dorothy Schilling's realistic portraits in colored pencil. Hours: Tuesday-Saturday, noon-6 p.m. Call 667-3483.

On Thursday at Zenith, Washington wood artist Margery Goldberg will speak to the Washington Woodworkers Guild, 7:30 p.m. Call 938-1027. GLASS

The Del Mar Va Depression Glass Club will hold its 10th Anniversary Show and Sale of Depression-era glass Friday, 6-9 p.m. and Saturday, 10 a.m.-5 p.m. at the National Guard Armory, 7100 Greenbelt Rd. in Greenbelt, Md. Call 565-2361.

Neil Duman's glassworks will be on display starting Friday at The Craftsmen of Chelsea Court, 1311 Conn. Ave. NW. Duman combines the sculptural glass with the more conservative vase and weight forms. The show runs through the end of the month and can be viewed Tuesday-Saturday, 10 a.m.-6 p.m. Call 466-3142. CRAFTS

The National Cathedral School, Wisconsin Ave. at Woodley Road NW, will offer classes including calligraphy, quilting and applique, knitting, ceramics, photography, painting, sculpture and drawing weeknights beginning Oct. 5. Call 537-6348 for dates and fees.

Dominie Nash will teach a two-day workshop on fabric dyeing and printing Oct. 7 and 14, 10 a.m.-3 p.m. at the North Chevy Chase Recreation Center, 4105 Jones Bridge Rd. in Bethesda. Fees: $17.50 for Montgomery County residents; $19.50 for non-residents. Call 530-3789.

Oatlands Plantation (a property of the National Trust of Historic Preservation), in Leesburg, Va., will offer needlework classes this fall starting Saturday. Classes including smocking, needlepoint design, needlepoint and cross stitch. Call (703) 777-3174 for fees and directions.

FAIRS

The National Colonial Farm, 3400 Bryan Point Rd. in Accokeek, Md. will hold its 11th Annual Harvest Festival Saturday, 1-4 p.m. Craftspeople will demonstrate life on a 18th-century tobacco plantantion. Call (301) 283-2113.

DEADLINES

The Fairfax County Park Authority asks artists and craftspeople to submit applications for the Fifth Annual Arts and Crafts Festival to be held Dec. 5, 10 a.m.-5 p.m. at the Wakefield Recreation Center, 8100 Braddock Rd., Annandale. Registration closes Oct. 16 at 9 p.m. Categories include woodcarving, stained glass, jewelry, leathercraft and ceramics. Fifty-seven display areas, each measuring 7 1/2 feet by 10 feet, are available. The $15 entry fee should be enclosed with the application along with a photograph of the craft. The park authority will charge an additional 15 percent commission on all sales. Call 321-7080.

COLLECTIBLES

"Treasures of Our Ancestors" is the topic for the 23rd Annual Fall Alexandria, Virginia Forum, which will be held at the Old Town Holiday Inn Thursday, Friday and Saturday. The forum, chaired by antique collector Dr. Arhutr J. Mourot, will include lectures on glass, auctions, 18th century prints, Maryland furniture, the Garbisch auction and collectors collectors Helen and Henry Flynt. Fees: $65. Call 683-1853.

"Discovery Time" will be held Friday, 6-10 p.m. on Kensington's Antique Row, Howard Avenue in Kensington. A panel of ten dealers and collectors will provide verbal appraisals of your small antiques and memorabilia, free. Also, refinishing and restoration experts will give demonstrate how to care for your heirlooms--including the care and cleaning of fine rugs. Advice will also be given on insurance and how to guard against theft. Call 836-4161.

The Antique Center, S. King St. (Rte. 7), Leesburg, Va. will hold an outdoor antique show Saturday and Sunday, 10 a.m.-5 p.m. Free admission. Call (703) 777-5358.

If you have an item for Etcetera, please send it and any black and white photographs to ETC., The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. All items must be received at least 21 days before publication and include a number where readers can obtain more information.