Keep Pots and Trays of Seedlings from Drying Up

The everyday plastic bag is the secret to success with keeping pots and trays of seedlings from drying out. Here's the way it works; I'll be arbitrary, then you can adapt the idea to your situation. Fill a 5-inch pot, clay or plastic, but clean, with any soil-less or sterile planting medium traditionally used for starting seeds - vermiculite and milled sphagnum moss are two great examples. Moisten well.

Sow seeds, according to packet directions for each kind; if none are given, sow half covered to the depth of their own thickness, merely press the rest into the planting medium surface. Set the seeded pot in a basin of lukewarm water to soak, until beads of moisture show on the surface. Allow to drain a few minutes, then place in the bottom of the plastic bag and draw its edges up and over the pot, gathering them together at the top and securing with a rubber band. Unless you have instructions to the contrary for the seeds you are planting, it is a good general rule to provide sown seeds temperatures hovering around 70-72 F. There is a warm enough place in most dwellings, even where energy conservation is severe in winter; the top of your refrigerator is usually a great place. Here are a few tips to help you in deciding where would be best to place it to help the seeds come to life.

(1) Set the sown seeds where temperatures are constantly between 68 and 75 F; the closer to 70-72 F the better.

(2) At this time strong growing light is generally not needed, nor is it to be avoided, unless of course it is extremely hot, as in warmer weather. As soon as seedlings appear, however, it is necessary to move them into good growing light. Remember this rule of thumb: Cool temperatures plus strong light equal short growth; warm temperatures plus weak light equal tall, spindly growth.

(3) As the seedlings sprout and show their welcome green, it is your task to open the top of the plastic bag a little at a time - but not on a rigid schedule, only when you can get to it. This gradually accustoms the seedlings to fresh air, and assures that they will adapt without setbacks or losses.

(4) Within two weeks after you've placed seedlings in strong growing light and they appear promising, begin fertilizing, a very dilute solution with every watering.

(5) Before seedlings crowd, transplant to individual small pots, or an inch apart in community flats. This time you may want to switch to a more usual soil based potting mix, such as equal parts garden foam, peat and sand. You can still use plastic bags to help seedlings get over transplanting shock. Just don't leave a plastic "greenhouse" sealed with the hot sun shining directly on it or you may have roast giant ruffled petunias instead of healthy transplants.

Source: Braunstein, Mark Mathew Sprout Garden - Revised Edition 1999