Winter Salad Bowl (cont)
By: Jack Ruttle
Spinach (Spinacia oleracea)
The buttery, soft leaves of spinach go much further in the salad bowl than they do in the pot. The plant will germinate and grow at temperatures in the 40° Fs. Coleman's favorite variety for winter is 'Tyee', but he says that 'Indian Summer' and 'Winter Bloomsdale' are almost as good.
Two weeks before first frost, Coleman begins to plant spinach in frames for late fall harvests. The planting in frames can continue for the next four weeks. In frames that are later covered with tunnels, the spinach harest can continue all winter. Spinach planted outdoors at the same time, then covered with mulch when the temperature approaches 20° F, will survive the winter and yield the earliest possible crops. A couple of weeks after frost, he'll plant more in frames outside the tunnel. That sowing won't get big enough to harvest for winter salads, but will winter over and produce an extra-early crop as winter ends.
By adding a polyethylene-covered tunnel over his cold frames, Coleman figures he has moved his winter garden two or three zones south, varying with the severity of his zone 5 winter. In places with mild winters, tunnels are dry and pleasant places to garden all winter, and thus may be preferable to frames.
- The smallest comfortable size for a tunnel is 12 by 12 feet.
- A small tunnel will cost about $300, from kits or plans.
- In the off-season, move or reassemble the tunnel to another spot and force early tomatoes or melons. Move back over frames in late autumn.
- Tunnels offer 5° to 15° F of frost protection at night but become 15° to 40° F warmer than outside during the day.
Coleman's Cold Frame Tips
Eliot Coleman builds and uses cold frames artfully. His frames are four feet long and eight feet wide.
Here are ways to make and manage a cold frame in your garden:
- Build the frame on a smooth, flat surface. But when you set it in the garden, turn it upside down so the joints at the corners will be flat, and the fit between the window and the frame tighter and less drafty. Orient the sloping side to the south.
- Use 1-by-12 lumber for the back of the frame and 1-by-8 for the front.
- Size your frame to suit the windows you have, or make your own windows.
- When in doubt, vent it. It's better if the frame is too cool during the day than too hot.
Jack Ruttle is a former editor at National Gardening.
Photography by National Gardening Association and Suzanne DeJohn/National Gardening Association