How to Thin Out Seedlings for Healthier Plants

It’s important to thin out seedlings.

Because do you carefully measure every little seed in your garden when sowing?

I definitely don’t as we grow food on a large-scale with little ones a foot! If you sow your crops too far apart, or if the seeds were older or have poor germination rates you’re wasting valuable garden space with empty spots of dirt which can encourage weeds.

Most gardeners don’t have precision sowing, you sow your crops closer together than you need to & thin out your seedlings later on to the right distance.

Because crops aren’t sown at the perfect distance apart you need to ‘thin them out’. What does that mean?

Thinning out your crops simply means removing them from the ground so the surrounding ones have the space to grow.

Not thinning out your crops is a common beginner mistake because many are too scared of ‘killing’ a plant.

This results in little or no harvests, or poorly growing crops that struggle to mature in the right time frame. There are many thinnings (thinned out seedlings) you can eat though, and if not they make great compost green matter or fresh food for the chickens. However there are crops that you can sow densely to gain more harvests & maximize garden space.

Before I go into those details here are some reasons why you should thin out your seedlings.

Top reasons to thin out your seedlings

If crops are spaced too closely together they won’t be able to grow to the full-size because of root and nutrient competition.
Some crops will bolt sooner if they have no space to grow because they feel stressed out.
Your large crops like cabbage or broccoli won’t be able to reach its full-sized potential which results in crop loss.
If crops are too close together there isn’t enough air flow and this can potentially increase disease or pest build up.
Crops that grow underground like root veggies or large crops that need lots of root space for nutrient uptake are especially important to thin out. I hear many people unable to grow carrots and one of the first questions I ask is ‘did you thin out your seedlings?’

Thinned out seedlings you can eat

Lettuce
Spinach
Arugula, mustard greens
Roots with leafy tops like beets, turnips or radishes
Mesclun greens

Maximizing your garden space with dense planting

Although it’s important to thin out your crops, there are crops where you’ll benefit from dense sowings to gain more harvests. I sow many crops in blocks which become individual plants or rows later on. These crops are chosen because they can be eaten at multiple life stages.

Crops that are perfect to sow densely are anything leafy or with a leafy top that you can consume.

With lettuce, spinach, arugula, radishes, beets, turnips, any of the mesclun mixes and even large greens like kale, I sow more densely and harvest thinned out seedlings to eat. This makes a great use of space, so long as you harvest within the first few weeks so the rest can grow to a large-size. You’re essential harvesting either micro greens or baby greens then leaving the plants to grow to a large size like head lettuce or a large kale plant. I do this because it reduces the weeding I have to do. Just remember that if you don’t thin them out eventually, you’ll stress out the plants and they won’t grow larger. I discuss this in-depth in my growing greens guide.

By sowing densely you can harvest edible crops instead of weeds.

How to Thin Out your Seedlings

Read the seed packet to know the recommended distance so the plant can reach maturity.
Use a ruler to make sure the distance is correct. After years of gardening I ‘guess’ rather than measuring exactly.
Choose the larger seedlings with more leaves if you want to eat the thinnings. Leave the smaller ones to grow larger.
If you care more about harvesting the larger-sized crop, and are just composting the plants, then leave the larger ones as they’ll mature faster. This is the case with crops like radishes or beets.
Remove the seedling gently from the soil, especially if the crops are very close together to reduce soil and root disruption. You might have to hold down the one you want to stay in the ground so it doesn’t pull up too.
Crops like kale or lettuce that you grew for baby greens in the spring, can be transplanted into another garden bed.