The Master Gardener Demonstration Gardens, located at the Agricultural Farm History Park, 18410 Muncaster Road, Derwood, MD, are open to the public from dawn to dusk, 365 days a year. To schedule guided tours by a Master Gardener for yourself or your group, call (301) 590-9650, Monday – Friday, 9 a.m. to 1 p.m., March through October.