Now is the time to start seeds indoors in North Country, says natural resources educator
Sunday, March 16, 2014 - 5:12 pm


Apparently, infants lack object permanence. To them, a toy or face that disappears from view ceases to exist, which is why peek-a-boo is such a riot for little tykes. Most children outgrow this phase by age two, but this year I’ve regressed into “season impermanence.”

I’ve started to doubt spring exists. It has been so long since I’ve seen the garden—or any patch of bare earth—that some days I wonder if we’ve slipped into the perpetual winter of C.S. Lewis’ land of Narnia.

Even while we remain snowbound, the days are growing longer and the sun is getting higher; robins are singing, and there’s a good chance spring will come sometime in 2014.

For those who still believe in spring, late March is the time to start planting vegetable and flower seeds indoors. Raising your own plants gives you the option to pick unusual varieties not available commercially in the spring, and it’s a lot cheaper than buying transplants. For kids it can be a fun activity, and for the rest of us it’s at least in part about seeds of change, a sign we believe growth and change are possible despite a bleak forecast.

Considerations for starting plants indoors are timing, containers, growing media, light, water and temperature. Seeds are helpful, of course, as are seed-packet instructions, which tell you how long before the last average frost date to sow seeds indoors. The problem is that this varies. In Waddington, for example, the average last frost date is May 3, whereas in Star Lake it’s May 30. For most of St. Lawrence County it’s May 20, although many old-timers still consider Memorial Day the time to set out plants. You can search by ZIP code for last frost dates at

Any container at least three inches deep will work to start seeds if there are holes in the bottom for water drainage. Reusing commercial cell packs from garden centers is great, but it’s good to rinse them in a 10 percent bleach solution to reduce the incidence of damping-off and other diseases.

Garden soils often harbor disease spores that can kill seedlings in an indoor environment, and a sterile “soil-less” growing medium from a garden center is a good investment. These mixes usually contain peat moss, minerals such as perlite and vermiculite for good aeration and water retention, and sometimes a slow-release fertilizer. Plant a few more seeds than you need in case not all germinate—you can always thin them later, and don’t forget to label each container or tray.

Because direct light is critical, even a large south-facing window is not really enough for indoor starts, which will become leggy and be prone to breakage without additional light. Ordinary 40-watt fluorescent tubes are just as good as expensive grow lights as long as you pair a cool-white tube with a warm-white tube in each fixture. Lights should be suspended between two and four inches above the foliage, and should be on for 12 to 16 hours a day.

Temperature is important, especially during germination when soil should be kept at 70-75F. Keep containers off windowsills during germination, as nighttime cold can lead to seed rot and poor germination. Once the seedlings are up, cool-season plants like lettuce, onion and cabbage-family crops do better at 55 to 60 degrees, whereas warm-season plants like tomatoes, squash and marigolds prefer it 65 to 70F. Pay attention to watering—small containers dry out quickly. The medium should be kept moist but not waterlogged. Bottom-watering is best, but containers shouldn’t sit in water for over an hour.

After the first set of true leaves appear, you can add water-soluble fertilizer at half-strength every 2 to 3 weeks. When the second set of true leaves develop, you can transplant to larger containers. Then a couple weeks before last frost, begin to harden off seedlings. Set them outside in a sheltered, partly shaded spot on calm warm days, starting with a few hours at first, and gradually work up to full days.

Take heart—it won’t be snow pea and iceberg lettuce weather for much longer. May the seeds of hope, whether figurative or literal, sprout and thrive in your home this late winter.

For more information on gardening, call your Cooperative Extension office or email [email protected].

Paul Hetzler is a forester and Cornell Cooperative Extension of St. Lawrence County horticulture and natural resources educator.