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Thinning Plants in the Garden
by Don Janssen, UNL Extension Educator
One reason for removing weeds around your vegetable and flower seedlings is to reduce competition for the water, nutrients and sunlight that the seedlings need to grow. Gardeners who are quick to weed may be slow to thin crops, even though thinning crowded seedlings is equally critical to producing high quality crops.
Thinning is much like weeding, in that it reduces competition between plants. The ones that remain have room to grow and access to the sunlight, water and nutrients they need to grow and produce to their full potential. Thinning also improves air circulation around seedlings and so helps reduce the likelihood of some plant diseases from developing.
Fungal diseases such as powdery mildew are more likely when the air around plants is humid and plant foliage remains wet for long periods. Crowding by weeds or other flower or vegetable plants limits air movement around foliage and slows drying after rain, dew or overhead irrigation.
Crowded plants are harder to treat for insect or disease problems because sprays or dusts have a hard time penetrating dense foliage. Poor coverage translates directly into poor control.
So, with all these good reasons to thin, why do so many gardeners neglect it? Perhaps because it seems wasteful to buy and plant quality seed and then yank up the perfectly good plants that result from sowing it.
One way to counter that is to leave crops such as lettuce, carrots and green onions in place until the plants are big enough to eat, then thinning them. Transplanting thinned plants rather than discarding them is another option.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office
Contact InformationUniversity of Nebraska-Lincoln
in Lancaster County
Web site: lancaster.unl.edu
444 Cherrycreek Road, Suite A,
Lincoln, NE 68528