After Seeds Have Sprouted in Indoor Greenhouse Trays, Should I Remove the Clear Plastic Lid? And Do I Need to Move Them to Bigger Containers?

| 4/1/2009 12:00:00 AM

Tags: greenhouse, seeds,

When tomato and pepper seeds have sprouted in their indoor greenhouse containers, is it OK to let them continue growing in there after they’ve hit the ceiling? Or should I remove the clear plastic lid and let them continue to grow in their little containers? Or do I need to move them to bigger containers once they reach a certain height?

Those clear plastic lids that are often sold with seed-starting trays are really not necessary. (Mostly, they are a way for stores to charge a Transplanting Tomatoeshigher price.) All they do is help keep the soil moist until the seeds sprout; after that you should remove them so that the seedlings can grow without artificially high humidity.

Seedlings may need to be moved to bigger containers before it’s safe to set them out into the garden, but this will depend on when you started the seeds and how large your initial containers are. In general, once the plants have grown to about two times as tall as the height of their container, they should be moved to bigger containers if it will be a week or more before you can put them in the ground. But young plants are pretty sturdy and can cope with smaller-than-ideal containers for a week or two, as long as you keep them watered well.

And be sure to “harden them off” before you plant them into the garden. To do this, move them from indoors to a shaded, sheltered spot outside for a few hours each day. Then gradually increase the time you leave them outside each day, and move them to sunnier spots. (If you move them from indoors directly into full sunshine, the leaves may sunburn, just like we do if we are in the sun too long.)

—Cheryl Long, editor in chief

Photo By Walter Chandoha

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