Where plants are not to be transplanted twice, but remain in the plant
bed until required for setting in the garden, it may be necessary to
thin them somewhat. This part of the work should be done as soon as the
plants are large enough to pull, and before they begin to "draw" or
become spindling from crowding.
When thinning plants in the plant bed it should be the aim to remove
the centers of the thick bunches, leaving the spaces as uniform as
possible. When thinning the rows of seedlings in the garden the best
plants should be allowed to remain, but due consideration should be
given to the matter of proper spacing. Failure to thin plants properly
will invariably result in the production of an inferior crop.
There is a tendency for some gardeners to leave the plants of carrots,
onions, and similar vegetables too thick, or to defer the thinning
too long, with the intention of making use of the thinnings. Usually
this is a serious error, except in the case of beets, which can be
used quite young for greens. The crowded seedlings do not reach edible
size as soon as they would if not crowded; and the removal of part of
the crowded plants when they are wanted for the table is likely to
seriously disturb and impair the growth of those which remain. A better
plan is to make at least a preliminary thinning as early as possible,
leaving the plants perhaps twice as thick as they are eventually to
stand; and then to pull out every other plant after they reach edible
size. This method of thinning is especially adapted to beets, carrots,
lettuce and onions. The other root crops, like parsnips and salsify,
should be thinned to the full distance at the first thinning.--(U. Wis.
Cir. 16; F. B. 255.)