When it comes to starting seeds outdoors in flats, nothing ensures germination better than a few sheets of wet newspaper.
This year, in an attempt to beat the feast-and-famine syndrome of the vegetable garden, I am sowing a flat of lettuce and kohlrabi - two regulars at our dinner table - every two weeks. This way a consistent supply of these vegetables will be available all season. Newspaper makes a valuable contribution to this program.
Tiny seeds must be covered by only a fine layer of soil (1/4 inch at the most) if they are to germinate. But so thin a layer of soil can dry out very readily, and even a temporary drought in the region of the seed will terminate germination.
This is where the paper covering comes in. It prevents the soil from drying out and moderates soil temperature. I find flats treated this way can be left out in full sun and heavy rain.
Let's take, for example, the lettuce and kohlrabi seed I sowed the other weekend. After scattering the seed over the surface of the soil, I covered it with a ''dusting'' of potting soil and watered it well. Then I took about 8 sheets of newspaper, cut just a fraction larger than the flat, and soaked it thoroughly in water. This was pressed down lightly over the soil.
Having the paper slightly larger than the flat molds it into shape like a shallow pan. It also fits tightly enough so that even when it dries out in the sun it stays in place despite prevailing winds.
Moreover, even when the paper dries out it remains an effective mulch, keeping the surface of the soil moist.
Another plus for the paper: The seeds don't get washed out in heavy rain.
Inspect flats daily, since I find seeds germinate very rapidly under the paper once the frigid temperatures of early spring have gone by. As soon as several of the seeds have germinated, I remove the paper in the early evening (rather than in midday, so the seedlings are not suddenly thrust into the intense heat of the sun).
I also place the flats in that part of the garden that gets only morning sun. One day of this treatment is all that is necessary in my area. Then the seedlings accept full sun without any problem.
Right about now, in latitudes as far north as Boston, it is time to sow seeds of cabbage, broccoli, cauliflower, and Brussels sprouts for a fall harvest. While nurseries and garden centers offer a wide range of vegetable seedlings in the spring, they never bother to supply seedlings for a fall crop. But when a paper mulch helps seeds sprout so easily, this should prove no real hardship to the gardener.