Gardeners shouldn’t get too excited about the unseasonably warm weather that’s brought an early dose of summer in recent days.

Temperatures will cool down and frost could return, destroying anything that’s planted early, according to officials at the University of Maine Cooperative Extension.

Meanwhile, the warm spring weather could affect crops, ornamentals, fruit trees and flowers, according to David Handley, extension vegetable and small fruit specialist at Highmoor Farm in Monmouth. Temperatures that reached into the low 80s Wednesday and Thursday could force early blooms for daffodils and other plants, he said.

“We can enjoy it while we can, but let’s hope it doesn’t push things along too fast,” Handley said. “My biggest fear is we could face a repeat of 2010, which from a berry perspective was glorious and everything came out really early. But in mid-May, we got hit with a pretty hard frost.”

Many apple growers suffered two years ago when frost killed their apple blossoms. Paula McDougal, of Lakeside Orchards in Manchester, said she is extremely worried that there could still be a frost.

“Two years ago it happened and there was a crop loss,” McDougal said. “This year it’s similar. The trees are confused and if they bloom too early and then there’s a frost, it’s very dangerous. You can lose a lot of apples.”

University of Maine Cooperative Extension Horticulturist Kate Garland says spring in Maine almost always comes with surprises, but warned that cool weather will return.

“It’s going to happen,” Garland said. “We don’t know how cold it’s going to get, but it’s very likely we’ll get freezing temperatures. Plus, our soil temperatures are quite cold as well.”

Garland said people could use extension strategies if they are interested in planting — for example, a mini-greenhouse or a low tunnel made of plastic or spun fabric stretched over crops.

“You’re not going to put seeds in the ground yet because it’s too cold right now and they would rot,” she said. “I tend to recommend things a little bit on the safe side. I recommend planting seeds when soil temperatures get to 65 degrees. Some plants can tolerate colder temperatures, but that translates into late May, early June.”

Tim Sparrow, of Sparrow Farm in Pittston, said he would hold off to put out tender plants even though the frost is out of the ground in some places.

“The soil is still cool, but warming up,” Sparrow said. “I wouldn’t put out tender stuff. Maybe if you have a hoop house or something covered it would be all right. It’s warmer than average, but we usually get a late cold spell and could lose everything.”

Elmer Elvin of Elvin Farm in Readfield also warns against planting too early. He said plants in greenhouses are safe, but it is still too early to plant outside. He said there is a risk they could be killed by frost despite the unseasonably mild temperatures.

The benefit of a late spring frost? It could kill some insect pests, including black flies and mosquitoes, according to Glen Koehler, pest management scientist at the University of Maine.

Garland said it isn’t too late to prune ornamental shrubs and apple trees and blueberry bushes.

“We have YouTube video clips that are very easy to watch,” she said. “They’re right on our website,” which is umaine.edu/gardening/videos.

John Jemison, extension water quality and soil specialist, recommends preparing gardens for planting.

“I wouldn’t want to be rototilling the soil — it’s still petty wet out there,” Jemison said. “But you can pull up old plants and rake. I also like to remind people to stretch out and get limbered up before you go out. A lot of people charge out there to do raking and haven’t been that active.”

Mechele Cooper — 621-5663

mcooper@centralmaine.com