Sprouting Seeds Indoors – Is it Time?

Sprouting Seeds Indoors – Is it Time?

By Marilyn Shy

The days are getting longer. Even though there is a thick layer of white covering everything I can see, there is a hint of spring in the air as the sun climbs higher into the sky each day. I can feel it, and I can almost taste it. Plus there are all of those seed catalogs stacked up on my desk. Could it be time to start planting seeds indoors? Well….maybe!

If you are an avid gardener like me, you can hardly wait to get into the dirt and watch the annual beauty of seeds unfold as they sprout and turn into full-fledged plants. I have learned through trial and error that I can start seeds successfully under my grow lights by about the first of March. Any earlier, and they get too big too fast, and then I am so anxious to get them outdoors and into the ground that they inevitably don’t survive those late season cold snaps.

But since I have a small hoophouse I find I can transplant my baby starts into it toward the end of March. The hoophouse is quite amazing. For the first few weeks, if I cover each plant with a small glass jar, and then put what is called a floating row cover over all of the plants, inside I find they will make it through even the coldest nights (below freezing and even into single digits). A floating row cover looks like a thin white blanket that is translucent, so that light can penetrate during the day, yet it traps heat from the ground at night. If you have a cold frame, you may be able to start seeds early as well.

Otherwise, if you plan to transplant your starts directly into your garden, it is probably best to wait until mid-April or so to start your plants indoors. Experts say the best time to plant seeds indoors is 6-8 weeks before the last killing frost. Our last killing frost is generally toward the end of May.

My best success comes with plants that can tolerate a bit of cold, like lettuce, broccoli, cabbage, spinach, bok choi, kale and collard greens. I also like to use a heat mat, specially designed for sprouting plants that will keep your soil at the optimum temperature.

I also like to use the plastic 6-packs that you get when you buy transplants commercially. I find them to be just the right size, and they all fit nicely into a flat that has a clear plastic cover about 2 inches high. It is made specifically for seed sprouting. In this way I don’t have to water at all until the plants sprout. But you can use any clean containers. Egg cartons are a nice size. Just be sure you poke holes in each cell for drainage. After planting, cover the entire carton with a layer of plastic wrap to keep the soil nice and moist. As soon as you see the plants emerge, you must take off the plastic cover.

I like to plant 2 seeds per cell. Since you won’t have 100% germination, some of the cells will end up with just one plant. For those that have 2 plants, you can either pinch one off, or transplant both of them into another container. From the 6-packs, I often transplant the baby plants into 5-ounce Dixie cups, again with holes poked into the bottom of the cups. I find that I can leave the plants in the Dixie cups for a long time if need be. They are also handy to give away, as I usually end up with about twice as many plants as I can use. People love getting baby starter plants.

It’s essential that you harden your plants off before they go from the house into the garden. Hardening off is a process whereby the plants get used to the harsher conditions outdoors before you put them out for the rest of the season. If you do not, the plants can get windburn, or sunburn, and will likely die as a result. This is heart breaking after all the time you spent indoors nurturing them as babies. When you first put them outside, place them in the shade in an area protected from the wind for a few hours, and bring them in each night. Increase the amount of time you have them outdoors each day. After about a week, they should be ready to get transplanted into their final home.

If you have never planted seeds indoors, give it a try. You will learn something new each time you do. You will learn as much or more from your failures as you will from your successes. Before you start, read as much as you can about the process, then order your seeds and start planting! Sprouting seeds in the chilly days of early spring gives us all a preview of the warm days of summer ahead. And a little dreaming about that future time is an activity I highly recommend.