The sun had not quite finished rising on Saturday when, at 8 a.m., people began pulling green buckets from a stack and opening plastic bags they intended to fill with fresh blueberries and raspberries they picked at Robert and Eva Hamilton's Hybridoma Organic Fruit Farm, in Baldwin.The pick-you-own farm had a delayed opening this year thanks to a rainy spring that caused the berries to take longer than usual to ripen. Weeds also won the battle against many red raspberries, forcing the Hamiltons to plow under the beds. Still, Robert Hamilton was in good spirits on opening day, driving up to the entrance of the farm on his tractor and waving to families walking by."I wouldn't call it troubles," Hamilton said of the delay. "The plants are very happy."The blueberries were ripening Saturday at Hybridoma Organic Fruit Farm, in Baldwin.Hamilton, a professor of medicine and pathology and director of dermatology at Johns Hopkins University School of Medicine, said he started the farm because of a challenge. The state beekeeper inspector told Hamilton he would never find blueberry honey in Maryland because the berries do not grow in the state."I've been proving them wrong," Hamilton said. "Trying to at least."Hamilton and his wife have run their certified organic farm for 23 years, though it has been open to the public only for five years, as the Hamiltons had to wait for the plants to mature."It takes many years to grow these plants," Hamilton said. "You can't have people here if you don't have berries."The farm comprises 50 acres in the picturesque Long Green Valley. The couple grows 21 varieties of blueberries on the farm, along with a mix of raspberry and blackberry plants, apples and lavender. Hamilton also maintains a few beehives. The farm is open Saturdays and Wednesdays, with the weekday being popular with school groups and summer camps."The purpose of the farm is really education for the kids," Hamilton said.Hamilton saw many familiar faces on opening day, greeting everyone who walked by with "Welcome to the farm," and a smile. At the entrance he talked to families about babies born and gasped in surprise at children who have grown since he last saw them.Hybridoma Organic Fruit Farm is one of five pick-your-own farms in Baltimore County. The Baltimore County Agricultural Center and Farm Park, in Cockeysville, has sunflowers available from late July to early August. Mingodale Farm, in Parkton, offers vegetables and eggs on Wednesdays, Saturdays and Sundays. Weber's Peachberry Farm, in Glen Arm, sells blueberries, blackberries and peaches from June to August, while Wind Swept Farm, in Upperco, offers vegetables, such as corn and summer squash, which is available in July.'Eating them fresh'On Saturday, Carolyn Lorenzo said she was happy to make the 50-minute drive from Severn, in Anne Arundel County, to Hamilton's farm, where she and her husband picked black raspberries."We come out once a year, do this, load up blueberries and blackberries and enjoy," Lorenzo said.Julie Page, who came from York, Pennsylvania, was visiting the farm for the first time with her husband, who is from Maryland. She planned to stock up on blueberries, she said."I just like eating them fresh," Page said. "There's so many different things out there to try to make but eating them fresh is just as good."Brigitte Jacobson, from Baltimore City, said she returned to the farm again this year to spend time with nature and pick pesticide-free fruit."I love coming out here," Jacobson said.Normally she uses her berries to make a jam, but since her children are not fans of the flavor, Jacobson said she plans to eat her blueberries fresh."The ones that are leftover, I freeze them and we eat them on cereal in December," Jacobson said.Blueberries are priced at $4.50 per pound, while raspberries and blackberries sell for $5 per pound. Hamilton said he is experimenting with gooseberries and currants, adding that the prices on those and the lavender are posted on the day of availability. People can pick berries on Saturdays and Wednesdays from 8 a.m. to 3 p.m., but Hamilton recommends arriving early before the crop is picked out.As for recipes, Hamilton said he just enjoys keeping it simple with fresh blueberries."With skim milk!" he added.More information about pick-your-own farms is available at pickyourown.org.