|Generally speaking, when using one of those commercial windowsill "greenhouses" with the clear plastic lid, should you remove the lid once the plants have begun to sprout and let them continue to grow uncovered, or if not, how long should you leave the lid on?
|The dome is intended to maintain the humidity level. Since germinating seeds must not be allowed to dry out, this works quite well. Once the seeds have germinated however, it is usually better to remove the lid right away in order to promote air flow and reduce the risk of damping off or fungal attack. Some gardeners will however simply prop the lid part way open, especially if there are different stages of plants under the dome.|