Starting heirloom seeds indoors

The beginning of the year is the perfect time to think about spring's garden. I've resolved to grow a lot more heirloom plants from seeds this year. Although the definition varies slightly, the general rule is that heirloom seeds are passed down from generation to generation for more than 50 years. And with so many mass-produced hybrid varieties these days, heirlooms are getting lost in the crowd. Without ongoing efforts by companies and individuals to perpetuate their existence, many of these treasured varieties of the past have and will be lost forever.

First, of course, you have to get your hands on some heirloom seeds. There are plenty of catalogs and websites for folks who grow, sell and share these old-fashioned favorites. A good place to start your search is with Seed Savers Exchange in Iowa and Virginia's Southern Exposure Seed Exchange. Both specialize in heirloom seeds.

Timing is everything when you're starting seeds indoors. Too soon and the plants outgrow their containers. Too late, and you'll have small seedlings that have to be fussed over to survive. The key is the last frost date; the last spring date that frost could form in your area. Your county extension service can tell you this date. Classic summer plants can (usually) safely be set out after that.

Find the number of days the seed takes to be ready to set out; seed packets usually include this transplanting information. Then back-time planting from there. For example, summer squash takes four weeks, tomatoes about eight weeks. If your last frost date is April 15, start the squash mid-March and tomatoes mid-February. I don't worry about precise dates.

Start seeds in most any well-drained container. Butter tubs, plastic bakery boxes, even egg cartons are fine. Garden centers will have several options for purchase. A common and easy choice: 2 ¼-inch-square peat pots. Delicate seedlings don't need to be transplanted and the whole pot can be set directly into the garden without disturbing the plants.

When starting your seeds indoors, fill each planting area with soil-less seed starting mix. It's labeled as such, and typically includes sterile sphagnum peat moss, perlite and vermiculite. Don't use ordinary garden soil, which is full of disease-causing organisms and too dense to let young roots develop properly. Moisten the medium sufficiently with water so that it is damp like a wet sponge.

Heirloom seeds may not sprout as well as hybridized seeds, so plant three or four and thin out the weakest later, leaving one plant per pot. Cover lightly with the medium and then cover the entire tray with a clear lid or plastic covering. This allows light in and holds in moisture so the soil doesn't dry out. Refer to the seed packet for the proper planting depth, but a general rule of thumb if you don't know is four times the seed's thickness. Seeds germinate best in soil that's a little above room temperature. The top of the refrigerator supplies good bottom heat, but a commercial heating mat gives a more consistent temperature. It can help, but is not always necessary.

As soon as the seedlings emerge, remove the cover and place them in good light. An ordinary fluorescent shop light works just fine. Suspend about 2 inches above the leaves. Set a timer to give the plants 16 hours of light each day. Raise the lights as the plants grow, keeping the distance above the leaves the same.

Once the true leaves develop (the set after the ones that you first see), you can begin periodically using a very diluted mix of soluble fertilizer in warm water. But don't set them in full sun right away. Gradually harden them off over a week to 10 days by exposing them to more sunlight each time. Start with an hour and work your way up by an hour each day.

Give seeds the right conditions and they'll do the rest. A little warmth, the right moisture and light and a bit of patience, and you'll raise a crop of healthy, garden-ready heirlooms that can't wait to get out and start growing.

Joe Lamp'l, host of "Growing a Greener World"on PBS, is a Master Gardener and author. For more information, visit www.joegardener.com.