Thinning for Fat Veggies

If you direct-seeded earlier this spring or purchased plants at a nursery, it may be time to thin your seedlings! Thinning seedlings is an important task for maintaining plant health and ensuring plants have enough room to reach harvest size.

This arugula won't grow much larger unless it is heavily thinned.

This arugula won’t grow much larger unless it is heavily thinned.

Thinned seedlings have more space for air circulation, which helps to control fungal disease by reducing moisture retention on leaves. They also have more space for roots to find nutrients and moisture in the soil, helping plants get through dry periods and access the nutrients needed for growth. Crowded plants will compete with each other for physical space – anything planted too close together will have difficulty reaching the correct harvest size, such as with carrots and beets. Other plants may fail to grow large enough to support a bountiful harvest.

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These beets in 2′ rows should be thinned to 8 beets each.

To thin seedlings, make sure the soil is slightly moist. Plants will come out of the ground more easily if it is slightly moist, rather than very hard and dry. If it is dry, moisten with a little water several minutes before thinning. For small seedlings such as radishes or arugula, the entire plant, including the root, can be pulled out. For larger seedlings such as cucumbers or squash, cut the undesired plants at the soil level. Pulling larger plants may accidentally uproot the plant you want to keep, as they often have intertwined roots once they grow larger. For very thickly planted seedlings, especially where it is difficult to see individual plants, snip them as shown in our video. 

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The center radish should be left to grow, while the ones on the sides are pulled.

Thin seedlings to the correct spacing. This will be on the seed packet, but if it’s no longer available, try this: For root vegetables, try to visualize the harvest size of your plant. This may be 1″ in diameter for a radish or 2-3″ in diameter for a beet. Add at least 1″ of space on top of that and leave that total amount of room between each seedling. You may also refer to these spacing recommendations as a starting point.

Radishes thinned to the correct spacing.

Radishes thinned to the correct spacing.

Cucumbers are often over-seeded and sold without being thinned at nurseries. Be sure to remove the two weakest plants by snipping at the soil level, leaving one to grow to full size. Three cucumber plants in a too-crowded space will never yield as much as a single cucumber plant in adequate space.

Cucumbers are often over-seeded and sold without being thinned at nurseries. Be sure to remove the two weakest plants by snipping at the soil level, leaving one to grow to full size. Three cucumber plants in a too-crowded space will never yield as much as a single cucumber plant in adequate space.

After thinning, be sure to water the soil thoroughly, as removing plants can have a drying effect on the soil.

What to do with the “thinnings”? These small seedlings are a flavorful addition to many dishes. Top on sandwiches and salads or toss in your morning smoothie.