Skip to content

Starting Tomatoes In A Cold Frame

From tiny beginnings come great things, and the time has come to begin the tomato patch. We use a cold frame, not a hot house. The latter refers to a greenhouse, which is what many tomatoes are started in. Since we don’t have one, a cold frame will have to do. I think our method of starting transplants is a lot simpler than running a greenhouse anyway.

We just built a new cold frame. Cedar logs were laid down on either side of a 4-foot wide, 60-foot long bed. Posts were set 10 feet apart in the middle of the bed, 42 inches tall and with pitched tops. A five-inch wide, 10-foot long sassafras board was nailed lengthwise to a four-inch wide board, making a long v shaped beam. This was inverted and nailed to the tops of the posts, and two triangles were made for the ends.

This tent-like frame holds up the window sashes. Three barns yielded two truckloads of windows, all of which needed a good washing. One truckload of sand and one of compost had been worked into the soil. The top three inches were scooped up and sifted through half-inch hardware cloth set over a wheelbarrow. This was put back on top of the baked and raked evenly.

I let the bed rest for a day while the moon shifted over to a favorable planting sign. Then I took all the windows off and made shallow rows four inches apart crossways down the bed. Markers were made by sawing cedar strips into foot-long pieces and all the varieties were written on them. Planted in the first week of April, transplants will be ready for the patch by mid May.

After opening the packet, I pour the seeds into my left hand and try to place one every inch or so in the row. Most packets have enough for two rows, though my favorites get several rows. I cover them back up and firm the soil with the palm of my hand. The windows were left off while a gentle rain moistened the bed, and then were placed back on.

We will water occasionally and remove windows as necessary for good air circulation. When the seedlings emerge, the spaces between the rows will get stirred up and kept weed-free. In 6 to 8 weeks, hundreds of plants will be ready for transplanting out into the garden.

I have started tomatoes in trays then transplanted them to plastic seeding trays when they get their first true leaves. These six packs have potting soil in them and need to be kept watered or they’ll dry out. I’ve also used soil blocks, which are compressed potting soil with one plant in each block.

Both of these methods have the advantage of lessening transplants shock, because the roots are not disturbed as much when the plant is set out in the field. But I’ve found this isn’t important at all. We simply dig out our plants bare-root, keep them moist and get them planted quickly. They wilt for a day or two and come right out of it.

The cold frame method is more like an old-fashioned plant bed where tobacco plants are started. It requires less watering because the seedlings are rooted directly in the soil. I like to take the windows off and let them catch April showers.

The old window sashes are more ascetically pleasing to me then a plastic house. There is no plastic involved at all in our cold frames. I’ve considered building a greenhouse, but don’t see a good reason to. We could get an earlier start, with a lot more work. I like to keep things simple and in season. These little seeds will root directly in the earth, and give us plenty of transplants, who in turn will yield great harvest of tomatoes in the summer months to come.