A couple of dozen gardeners turned out on a chilly, rainy night for a free class in raised bed gardening.

Some went to the class at the Burden Center off Essen Lane in Baton Rouge to learn enough to garden with children. Most were longtime gardeners anticipating spring.

LSU AgCenter horticulturist Kiki Fontenot, who gave the first in a series of gardening talks, kept answering questions until, finally, she had to move the class to the back of the Burden Center conference room.

Fontenot and LSU AgCenter horticulturist Kyle Huffstickler met the gardeners at the back of the room to begin constructing small planter boxes of treated lumber.

Each gardener left with a finished, raised planter or boards and screws to make their own at home.

“We get the same questions from teachers and home gardeners over and over,” Fontenot said.

“I made a list of broad topics, one of those things you do between 2 a.m. and 4 a.m. when you can’t sleep,” Fontenot said. “I came up with about 16.”

Go to http://www.lsuagcenter.com to see what Fontenot and her LSU horticultural colleagues came up with or plan to attend future lectures at Burden.

Next up is “Starting and Growing Your Own Vegetable Transplants” April 11.

“The one I like is ‘What’s a Weed — What’s a Plant?’” Huffstickler said.

That one’s June 13.

All classes are free including anything made or handed out in class. The classes are from 6 p.m. to 7 p.m. at the Burden Center administration building, 4560 Essen Lane, at I-10.

Other classes are “Insect Identification,” Aug. 8; “Is It Ready to Harvest/Eat,” Oct. 10, and “Preparing Your Fresh Vegetables,” Nov. 14.

Call (225) 763-3990 for more information.

Either put a raised garden frame on concrete or scrape a grassy spot before filling the bed with dirt, Fontenot said.

Layers of newspaper pages or weed barrier cloth will help reduce the number of weeds, she said.

Planting after March 15 in Baton Rouge should prevent freeze damage to plants, Fontenot said.

Fontenot, who gardens with a small child, said treated lumber manufactured after 2003 is safe to use in raised beds.

Manufacturers became aware of the danger of heavy metals in treated wood in the 1960s. A law banning use of CCA (chromium, copper and arsenic) in pressure treated wood was passed in the last 10 years. The wood was used to build decks, fences, picnic tables and playground equipment.

For those who don’t want to use treated wood to make a raised bed, Fontenot suggested buying cinder blocks or using old brick, as long as the brick is unpainted.

For soil, Huffstickler recommended “garden mix” from the nursery or big box store. A good mix might contain soil, peat moss, sand, pine bark and composted cow manure.

A good garden center will have people who can talk about what to put in a raised bed, he said.

A raised bed’s side boards should be high enough to allow at least 8 inches of soil with room to add more as the dirt settles from watering and, eventually, decomposition of what’s in the dirt.

Vegetables need six to eight hours of strong sunlight.

“Your bell peppers will stay the size of golf balls if they don’t get enough sun,” Fontenot said.

“Put the bed close to a water source,” she said, “because your plants will need 1 inch of water a week.”

If you add manure or anything else to the soil in a raised bed, mix it in, Fontenot said.

“Just adding potting soil makes a hard pan,” she said. “Don’t layer. Mix!”

Mulching helps keep weeds down and reduces the amount of watering. Mulch with newsprint or pine straw. Leaves are good. Don’t use grass clippings as mulch if chemicals are used on the lawn. When using plastic mulch, allow for water to pass through to the roots of plants.

“You don’t want manure touching lettuce leaves,” Fontenot said. “Especially in a school garden.”

Fertilize, Fontenot said, with 13-13-13 fertilizer or fish emulsion. With everything used in the garden, she said, read the instructions on the package.

“When I started, some of my students had no idea where food came from,” said teacher Tim Mercer who gardens with his wife, Paula.

“Her father taught me, ‘The closer to the kitchen window the better you’ll take care of a garden,’” Mercer said.

Karen Zajac has gardened for 30 years. She just moved to Baton Rouge from Dallas.

“I’ve never built a raised garden,” she said. “I want to learn about the soil and plants here.”