Too Cold to Garden? Not True.
Don’t let the chill deter you from gardening.
This article is based on a Science Friday interview and was originally published on PRI.org.
Most people tend to think to think of gardening as a summer activity. Horticulturist Gerard Lordahl, however, says winter is the perfect time to pay attention to your garden.
“In the wintertime, right now I mean, people are protecting their plants,” Lordahl says. “Soil mulching is really important, and lots of our community gardeners are composting, and these are all things that can be done now. Protecting your plants through the winter, giving as much water to them as possible on those mild days, and then mulching.”
Lordahl is the director of the Open Space Greening Project, a community garden program based in New York City. He says there are a lot of beliefs about gardening in winter that are not true. For one thing, you don’t need to wait until spring to water your plants.
“Those days when it is mild, above freezing, you can go out there and try to water as much as possible,” Lordahl says.
The other thing you should be doing? Mulching.
“The surface of the soil is freezing,” Lordahl says, “ And that freezing and thawing is what causes plant root damage. So I can’t encourage your listeners enough to mulch as much as possible now that that surface is frozen. The problem is when it’s not frozen, rodents can live under that layer of mulch so now that the soil’s frozen it’s OK.”
Elizabeth Murphy, a soil scientist and author of Building Soil: a Down-Earth Approach: Natural Solutions of Better Gardens and Yards, says winter is also a good time to focus on your garden’s soil, whether you have an outdoor garden, or a collection of pots indoors.
For those wanting to start seeds indoors, Murphy says it’s important to get the soil recipe right.
“When we’re talking about starting seeds, we really want to make a potting mix that has really good drainage,” Murphy says, “We need to use either sand or vermiculite to to get that drainage. And we want to use material that holds a lot of water and releases some nutrients.”
If you’re going to be using soil from outdoors, Lordahl says it’s important to make sure it’s been sterilized.
“The problem is there’s a disease called damping off that could affect young seeds and it could kill the seeds,” Lordahl says. “So cooking your soil 200 degrees for 20 minutes is a good thing. Or use sterilized soil, so you don’t get these diseases attacking your seeds.”
For those wanting to get the soil right in their outdoor gardens, Lordahl suggests getting a pH test done.
“All those different elements can have an effect on the soil. Putting down lime increases the pH range of your soil and adding sulfur decreases it,” Lordahl says. “Here in New York City, we have issues with our pH because we’re surrounded by a lot of concrete. We encourage home gardeners and community gardeners to have their soil tested with simple ph test kits and then adjust it accordingly.”
But for those who just want a little bit of bloom or green in the middle of winter, there’s always the time-honored tradition of forcing daffodil, paper white and tulip bulbs indoors. Lordahl suggests using the refrigerator.
“[Bulbs] need that cool temperature, but not freezing, to develop a root system that will enable them to get through the winter,” Lordahl says. “So the refrigerator is a place where people could replicate that cold chilling temperature without freezing. If you put your daffodils that you haven’t had a chance to plant in the refrigerator in a brown paper bag — dark and dry for about six weeks or so—you’ll replicate that outdoor temperature. And you’ll be able to force those daffodils indoors. You could then repot them. I’ve had success doing it myself.”
Elizabeth Shockman is a freelance journalist who lives in the Twin Cities. Previously she worked as a PRI staff member and freelancer, reporting primarily from Moscow and around Russia.