Galveston County Master Gardeners program with Heidi Sheesley. 9–11 a.m. at the Wayne Johnson Community Center, 4102 Main, La Marque; aggie-horticulture.tamu.edu/ galveston. Autumn container gardening clinic: 10:15 a.m. at Cornelius Nursery, 1200 N. Dairy Ashford and 2233 S. Voss; calloways.com/clinics. Fall festival with plant societies, local artists specializing in garden art, children’s activities. 8 a.m.-4 p.m. at Mercer Arboretum and Botanic Gardens, 22305 Aldine-Westfield, Humble; 281-443-8731; hcp4.net/mercer. Build your own compost barrel workshop: 1-3:15 p.m. and 3:30-5:45 p.m. at the Houston Arboretum and Nature Center, 4501 Woodway; 713-681-8433; register at houstonarboretum.org. $80 members, $95 nonmembers. Share homegrown vegetables and fruit; fill out form for pickup at pearlandcommunity gardens.com. Drop off donations 8 a.m.-noon on the second and fourth Saturdays at the Pearland Community Garden booth, Pearland Old Townsite Farmers Market, 2243 N. Grand Blvd., Pearland. Gardeners by the Bay Garden Club meeting. 9 a.m. at University Baptist Church, 16106 Middlebrook Drive, 281-474-5051. Nottingham Country Garden Club meeting. 9:30 a.m. at the Municipal Utility Building 81, 805 Hidden Canyon Drive, Katy; 281-579-7017; nottinghamgardenclub.org. Organic Horticulture benefits Alliance-Texas AgriLife event. 7:30 a.m.-3:30 p.m. at Texas AgriLife Extension, 3033 Bear Creek Drive.