Nurturing Spring Seedlings

Most important, consider the needs of the plants you're starting. Change places with them on the windowsill for a moment, and make sure to properly use whatever system you choose.
PHOTO: JEFF MERMELSTEIN

There are lots of ways to nurture those tender spring seedlings before the join your spring garden. 

Nurturing Spring Seedlings

My first seed-starting container was a cutoff milk carton I'd saved from the school cafeteria. It made a fine and frugal little plant nursery. Of course, milk cartons still work, but today's home gardener can also choose from a confusing array of commercial seed-starting systems. What about these setups—are they gimmicks or godsends? How much do they cost, how long do they last, and how well do they work? To find answers to these questions, I put eight different seed-starting setups through three trial plantings. To begin, I planted a selection of vegetables and flowers, including lettuce, tomatoes, broccoli, celery, squash, marigolds, sweet Williams and zinnias. In later tests, I grew only kale from the same seed batch, so I could better compare seedling sizes.

All but one of the systems produced fine seedlings, but there were considerable differences in how each system worked and how easy it was to use. I comment on those differences and share my own personal preferences here. Still, different gardeners have different needs and opinions. Each of the eight seed-starting systems has supporters who prefer using it and who get good results.

So take my opinions with a grain of gardener's salt, and make your own choices. Most important, consider the needs of the plants you're starting. Change places with them on the windowsill for a moment, and make sure to properly use whatever system you choose:

• Use a good soil mix. (A good homemade recipe is five parts shredded leaf mold or compost, five parts good fine topsoil and two parts of sharp sand. Adjust it if your soil is unusually heavy or light.)
•  Keep the soil constantly moist until the seedlings germinate. Water thereafter whenever the top half-inch of soil gets dry. And frequently use a diluted fish emulsion or fish and kelp mix, especially if the seedlings are growing in a sterile soil medium.
•  Provide adequate light. Windowsill seedlings will grow more slowly than those raised under artificial light. Fluorescent tubes work better than incandescent bulbs (they don't roast the plants) but need to be set up quite close to the starts and raised as the plants grow. The more tubes the better.
•  Keep seedlings warm. If you can provide bottom heat to the soil, the plants will do fine with cooler air temperatures. Indeed, up to a point, plants double their growth rate for every 10 degrees Fahrenheit rise in soil temperature.

Follow such steps and your seedlings won't end up longing for the great outdoors just so they can escape their seed starters.