A reader down in Homer questions where to grow lettuces, in this instance, corn salad, once they germinate. I love to hear that at least some gardeners are hard at work, even though we are in the middle of an Alaska winter.
Lettuces make a great winter crop. Growing your own salads is one of the easiest things to do under lights. I am referring to leafy or cos lettuce plants of almost any kind, not the slower head lettuces. Open, leafy varieties are easier to start from germination and tending all the way to harvest, which can be done by simply plucking immature as well as mature leaves.
The key to growing good lettuce, aside from enough light (14 to 16 hours a day), is to make sure the soil remains moist. Growing under lights can quickly dry out soil, so pay attention to it. I plant ours in 4-inch plastic pots, not clay ones, because the plastic doesn’t suck up water from the soil. I like the pot size because we can bring one into the kitchen and pick off it as needed, while the rest of the crop is under lights still growing.
Soil? I use what I have. There is way too much fear caused by alarmist garden writers who warn of harmful pathogens in used soils. Take it from me — I literally wrote the books and have a fourth in the works — if you start out with good organic soil, then don’t think twice about reusing it, unless you had disease problems while growing your last plants in it.
Why do I think reusing potting soil is a particularly good idea? Well, for one, if you are growing the same crop again, previous plants put out a substance called exudates and grow the microbial herd they needed to thrive in that soil. These bacteria and fungi are still there, waiting for water and some more root exudates to continue to breed and increase populations. These are the microbes that feed and protect your plants. Their presence is why you may not even have to fertilize.
As for temperatures, as long as it is above freezing, you can keep your seedlings anywhere. I prefer room temperature, so outside greenhouses and cold farms are not used. My father insisted his winter lettuces tasted better when grown at cooler temps. Lettuces grow fast enough that you can experiment for yourself in the remaining months — I repeat: months — of winter, and see which of us is right.
OK, I know a recurring theme in these winter columns is to persuade you to get some lights for your plants. Here is another excuse, especially since we are heading into seed-starting season and they will come in very handy — and let you start some of the good things that require much earlier starts.
There are so many different kinds of leaf lettuces. You can order some via mail, but local nurseries have seed, too, and always need supporting to ensure we don’t lose them.
You don’t need to get hung up on spacing seeds when planting. Sprinkle them as evenly as you can. Then you need to cover them up with just the thinnest layer of soil that will actually “hide” the seed. The soil should be kept moist at all times, but during germination it is imperative. I suggest creating a tent of sorts with some plastic wrap or a used, clear plastic bag from the grocery. Keep the condensation down by uncovering for a bit every day.
Finally, I guess this is one of those times when I should write back to my reader friend in Homer and suggest trying some Tom Thumb cherry tomatoes and some of those small carrots. Should I even include radishes? Why stop with just different varieties of lettuces when you can grow a restaurant-worthy salad in the middle of the winter.
It isn’t hard, just me and my friend in Homer say ...
Jeff’s Alaska garden calendar
Alaska Botanical Garden: Did you know about the summer camp for growing gardeners? Time to sign up. Check this and lots of other important info at alaskabg.org.
Mycorrhizal fungi: Seeds should be rolled in an endo formula. Get some.
Thrips: They are back according to some readers. Bt works, as does covering the soil so they can’t get in once they leave. Don’t water so much.