August 3 column: Season extension

Here is a link to the feature story I wrote in today’s edition of The Spokesman-Review: Gardening goes undercover. (or you can read my column lower in this post.) It’s about garden season extension so you can grow salad greens and other veggie crops through the fall and winter.

I have been so excited to write about this topic ever since conducting my own little experiment last year. I had intended to write about this from my own perspective until I happened to drive through Peaceful Valley last winter and saw Greg King’s amazing garden. At that point, I realized that he’s the expert and is the person I really should be writing about!

Before I forget, I took the above photo in King’s garden back in May because I wanted you to see his hoops and how he has the plastic covers pulled up and out of the way. But once there is frost danger, and throughout the fall and winter, those covers are pulled down over his raised beds.

Garden column: Season Extension

by Susan Mulvihill

If you happen to drive through Peaceful Valley during the fall or winter months, chances are you’ll see something quite unusual. In a front-yard garden, there are a dozen or so raised beds with plastic covers and a whole lot of plants growing in them.

This is the garden of Greg and Colleen King. They have been experimenting with the notion of extending the gardening season in a big way.

“This is our third year of doing this,” he explained. “We’ve learned what works and it’s been enjoyable to see how everything grows.”

Eliot Coleman’s thoughts on season extension

In “Four Season Harvest” (Chelsea Green Publishing, 234 pp., $24.95), author Eliot Coleman writes, “The surprise of our winter garden (and yours, too) is how simple it is. Winter vegetables will thrive in any winter climate with a little protection from wind and weather. No heating or high-tech systems are necessary. The keys to success are a new attitude and new crops.”

By the end of the traditional vegetable gardening season, most gardeners are ready to hang up their garden gloves until the following spring. Extending the season probably sounds like a great deal of work when it’s least appealing.

The great thing about winter gardening is that the only work one does — if you can call it that — is harvesting what you planted in late summer. There’s no weeding, watering or fertilizing involved.

How winter gardens work

Take a look at the accompanying list of crops that are cold-hardy. You’ll notice most of them are salad greens, something gardeners tend to miss the most during the winter months.

King first learned of extending the season through research on the Internet.

“I wanted to see what others were doing,” he said. “I saw low tunnels and high tunnels and how they were using them. Soon I realized I could from their successes and failures.”

Low tunnels vs. high tunnels

What are “low tunnels” and “high tunnels?” Coleman defines low tunnels as “lengths of plastic sheet supported by wire arches to make small plastic-covered tunnels.” High tunnels are simple, plastic-covered structures tall enough to stand in.

King turns his raised beds into low tunnels by placing hoops over the beds. These are made from bent-metal electrical conduit — located at either end of each bed — and heavy-duty black plastic sprinkler pipe for the middle. The plastic hoops are slipped over short rebar rods that are pounded into the ground at 2-foot intervals.

Plastic sheeting goes over the top and twine tied over the plastic holds it down in windy conditions. The twine allows him to pull up the sides of the plastic for harvesting or ventilating as the temperatures warm up in early spring.

“I use 6-mil greenhouse plastic which is UV-protected and guaranteed to last four years, although mine should last longer since I only use it for part of the year,” he explained. “Avoid using regular plastic sheeting from a hardware store because it becomes brittle in sunlight. My plastic came from online garden suppliers.”

Soil prep and seed-starting

To prepare the soil in the beds, he created a mixture of worm castings from his worm box, compost and minerals. King added an inch of this to the beds and covered the soil surface with 2 inches of shredded leaves because of their insulating quality. He uses compost tea to feed the plants.

He starts all of his seeds indoors under controlled conditions, usually the first to second week of July, and transplants them outside in August and September. It’s also possible to direct-seed from July to September.

King grows beets, carrots, salad greens and kale, and is quick to add that “nothing performs in the cold like kale. We’ve found lettuce becomes bitter and goes to seed more quickly than other greens.”

The garden has become a group effort and source of enjoyment for his extended family.

For those interested in extending their garden season, he recommends starting small and spacing plants well to avoid slug problems.

In Peaceful Valley, King’s biggest challenge is a lack of sunlight during the winter due to the Maple Street bridge and the hill behind his garden. He feels those in sunnier locations should have good success.

 “If you like gardening, you don’t really like that it’s over in the fall,” King said. “It doesn’t have to be that way. With this method, you can start earlier and grow later.”

Suggested winter vegetable crops

• Arugula
• Carrot
• Claytonia* (miner’s lettuce)
• Kale*
• Kohlrabi
• Lettuce
• Mache (corn salad)
• Minutina*
• Mizuna
• Radicchio
• Radish
• Scallion
• Spinach
• Swiss chard
• Tatsoi
• Vit*

*Exceptionally cold-tolerant

Note: Look for seeds at local garden centers. The online supplier, Johnny’s Selected Seeds (www.johnnyseeds.com, 877-564-6697) has an extensive line of seeds for salad greens.