Planting the Cold Frame

I was very proud of myself this winter when I finally got a decent cold frame built—and from all repurposed materials, which didn’t cost me a penny. I was even prouder when last week I took the temperature of the soil (with a meat thermometer!) and discovered it was five degrees warmer than in the surrounding garden: a balmy 69°F. In fact, I was so pleased with myself that I almost forgot that the whole point of a cold frame is to put some plants in it!

With the weather being so warm this winter, I probably could have set lettuce out in the cold frame a week or two ago. The normal outdoor transplant date for lettuce around here is about March 20 (four weeks before the last expected frost). Cold frames (I’m told) can usually extend the season by a couple of weeks. So I started some lettuce seeds indoors on Feb. 7, thinking I’d probably plant them out sometime in the first week of March. Well, yesterday was our sixth or seventh day in the 60’s this winter, so I decided it was well nigh time to put the lettuces in the cold frame. If I waited any longer, the “cold” frame would be a sweltering inferno, and of no use at all!

Lettuce (and onions) enjoying the sunshine

The process of planting the cold frame actually started the middle of last week, when I started hardening off the lettuce seedlings, by setting them outside for an hour or two more each day. This may not have been necessary, since in the cold frame they will be pretty well protected from wind and frost, but I didn’t want to take any chances. So I got them used to their new environment gradually. And I saw that they were taking to it. Their leaves were getting sturdier and more compact. The Bronze Arrow seedlings started taking on a redder cast. (This seems to be the case with a lot of plants. Direct sun makes their color more pronounced.) A couple of weaker seedlings appeared to succumb to the breeze and direct sun, but all in all, it looked like the lettuces were very happy to be outdoors.

Compost and fertilizer ready for digging in

So yesterday I prepared the soil in the cold frame. It’s sitting on previously cultivated garden ground, so there wasn’t too much to do in the way of digging. I spread a bag of composted manure over the surface, sprinkled 1.5 quarts of organic fertilizer on top of that, and gently dug it all in, while pulling out any perennial weed roots I came across. (I call this “pre-weeding.” It’s a lot easier to pull out one root now than to yank out grass seven separate times over the summer, each time afraid of uprooting more valuable plants.)

Once the soil was mixed and raked (passably) level, I started putting in the plants. I used a trowel to gently lift chunks of soil from the flat and then, holding them loosely in my hands, applied a little pressure with my fingers to encourage the chunks to separate naturally into individual plants. This is easiest to do when the soil hasn’t been watered in the last twelve hours or so. If the soil is too wet, it’s more like mud and doesn’t naturally fall apart.

I placed the lettuces in small holes dug anywhere from 6 to 12” apart. In the rest of the garden, I plant less intensively, giving the lettuces more like 12 to 18” each. This means I don’t have to water or fertilize as often, and weeding can be done primarily with a hoe. But since space is at a premium in the cold frame, I space the plants more like Mel Bartholomew recommends in Square Foot Gardening. For this small number of plants, I’ll easily be able to apply extra water and fertilizer as needed, and weeding on hands and knees won’t be too much of a chore.

The seedlings I’d started in my one little repurposed clementine flat were enough to fill my 18-sq.-ft. cold frame. I had five varieties: Jericho romaine, Deer Tongue, Bronze Arrow, Bibb, and Simpson Elite. The Jericho didn’t germinate as well as the others for some reason, so I only had two of those. But I had 6 Deer Tongue, 8 Bronze Arrow, and 12 each of Bibb and Simpson Elite. I was really surprised that the latter two germinated and grew so well, since the seed is from 2009. But I’ve been storing it in airtight containers in the fridge, and it’s apparently retaining its viability.

I watered in the lettuce seedlings with a little liquid fertilizer (Miracle-Gro, I sheepishly admit… it’s so darn easy…).

Between some of the lettuces, I planted a row of radish seed (Southern Exposure Seed Exchange’s Easter Egg mix). Radishes are ready to harvest in 3½ weeks, so by the time the lettuce needs the room, they’ll be out of there! (And the fact that radishes are a root crop means they don’t compete with the lettuce for the same soil nutrients.)

All's well so far!

Finally, I had just a couple of square feet left for some endive seeds. I planted Broad-leaved Batavian for the first time last spring, and a few seeds germinated, but the plants disappeared a week or two later. I don’t know what went wrong, but I’m trying them again this year. Maybe being in the cold frame will help. And I put six seeds to a station, for better odds!

Well, I checked on my lettuces this morning, and they all seem to have survived the night. If they can do that, they should be good to go. I wish I could just sit and admire them all day, encouraging their growth with positive thoughts. But I’m afraid I now have to get busy planting onions, before the rain moves in tomorrow…

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