How to Thin Seedlings – Thinning Chart – Cool Weather Crops

Every fall planting season I shuffle through seed packets to find out how to thin the seedlings. I simply forget. Sometimes it’s damp out in the garden, or it’s an uncommonly warm day. I would rather leave the seeds inside.

To solve this little inconvenience, I created a chart for cool weather crops. No more fiddling around with a bag full of seed envelopes.

How to Thin Kale Lettuce and KohlrabiGo ahead, print out this handy thinning chart. Maybe even laminate the thing!  Let your seeds stay put until the next time you need them.

More Thinning Tips

BEST TIME OF DAY TO THIN: At the coolest part of day and 10 minutes after watering. When it’s cool sprouts will be nice and plump and the remaining plants will be less stressed if you get too close.What are true leaves?

BEFORE THINNING: Water the soil to make it easier to pull extra plants. This reduces the chance that you’ll damage surrounding plants.

WHEN TO THIN: Some plants can be thinned at a certain height. For others, it’s best to wait until several sets of leaves develop. For many plants, it’s wise to wait to thin until a second set of leaves forms. The first leaves that form are called seed leaves or cotyledons. They hold nutrients. Sometimes you can see the seed casing still attached. The second set of leaves is referred to as true leaves. Usually true leaves come in a pair, although some plants develop just one true leaf to start and others get a few true leaves all at once. True leaves resemble the leaves of the mature plant. If you forget to label the area (I never do that, yuk, yuk), you can identify the plant by looking at the true leaves.

Seed leaves of lettuce are small and round in shape. The round leaves will grow further apart as time goes on allowing room for the true leaves. The true leaves will grow soon after and look different. They will stretch out farther than the seed leaves and will start to exhibit characteristics of the specific lettuce grown.

RAKE METHOD OF THINNING: Lettuce, spinach and other greens can be thinned by hand or with a flexible rake. Take one pass with the rake and then another pass in the opposite direction. The other option is to thin greens when they are tall enough to eat – my preferred method for greens.

SNIP OR PINCH OFF: Root vegetables such as beets, carrots, onions, parsnip and turnip should be snipped or carefully pinched off at the soil line to prevent damage to neighboring plants.

AFTER THINNING: Some gardening gurus remove all thinned plants to get rid of a scent that could attract pests. The carrot root fly is a good example of a pest that might be drawn to a newly thinned bed of carrots. Covering plants with a floating row cover for a few hours after thinning does the trick.

Do you have any thinning tips or a different approach for any of the plants listed?