When To Thin Seedlings?

The excitement of spring starts weeks or months before the warm weather arrives.

Spring anticipation begins with the planting of vegetable seeds for the garden and flower seeds for the landscape. 

thinning seedling lets you pick strongest Pin

Once seedlings sprout, it will soon be time to thin them out.

But, why and when to thin seedlings is a question many new to seed starting ask.

Table Of Contents

Why Should You Thin Seedlings?

Thinning seedlings helps them develop and grow stronger and faster. Seedlings not thinned have small stems and a leggy appearance.

When seedlings grow in a tight cluster (crowded plants) they fight for light and grow spindly. Use the 1/8 inch rule. When thinning, seedlings give them about 1/8″ inches between each new plant.

Related: What You Should NOT Do When Gardening

When Should You Thin Seedlings?

The best time to thin seedlings is up to six weeks after planting when leaves begin to show on the stems. 

Putting Seedlings to Work

Many gardeners love vegetable seedlings. The tiny seeds do not need individual sowing. You just broadcast or sprinkle them over garden beds or seed flats. 

Seedlings sprout in groups. We do not want this. Thinning a group of seedlings produces higher yields and more robust plants since fewer plants minimize competition for nutrients and water. 

The thinning also provides better air circulation between your plants. Lastly, overcrowded vegetation will inhibit growth, and plants won’t produce food fast, if at all.

When To Thin? Follow These Simple Steps

The best time to thin crowded seedlings is when you see at least two sets of leaves sprouting on your plants. On average, those plants are in the vicinity of two to three inches in height. This means they will be easy to grab and pull out of the soil.

Pulling the plants is an alternative to cutting them. Do your thinning while the soil is damp. This way, the roots slip out without necessarily disturbing other vegetation.

It’s advised you thin in the evening. You want to allow the remaining plants to adjust to the environmental change. Otherwise, you risk shocking the ecosystem with exposure to sunlight and heat.

Thinning of Seedlings: Is It Necessary?

It may not be as easy as thinning, but you can try separating seedlings. The chore of separation is far more tasking than thinning, though. Also, if you pull the seedling and, in some cases, cause damage to seedlings, replanting them won’t likely return the seedlings to health.

You have to consider if you have the room to space them properly. Your plants need adequate space, and you encourage growth with immediate attention to thinning. Putting off the process increases the possibility of stunting growth. 

This is detrimental, especially if you have short growing seasons. Plants need all the time you can give them to grow!

Choosing Which Seedling to Thin Out

Locate the healthiest, strongest, and most compact seedlings of the bunch. Those are the ones we want to keep. If all your seedlings are healthy, cut the smallest at the base. 

Don’t assume the tallest seedlings are the ones that should stay. If new and young seedlings are tall and leggy, the chances are they’ll grow weak, especially if they don’t get appropriate lighting. If your seedlings are relatively the same size, randomly thin them out.

Related: What A Good Soil Mixture For A Raised Vegetable Garden

How Much Thinning of Seedling?

If seedlings start life indoors, thin until there’s one seedling growing per pellet, cell, or seedling pot. They’ll have room to grow, and the process makes it easier to replant them in the garden.

Seeds sown in your garden should go through thinning following spacing recommendations you find on seed packets.

Time to Thin

Let’s get to work!

Your Toolkit

  • Garden snips or scissors
  • Kneeling pad (optional)
  • Flexible rake (optional)

What to Do

Figure Out Spacing

Your seed packages provide guidelines for spacing and sowing depth. Here are a few general recommendations.

  • Lettuce: 18″ to 24″
  • Parsnips: 3″ to 6″
  • Carrots: 2″ to 3″
  • Spinach: 2″ to 6″
  • Onions: 3″ to 5″
  • Beets: 3″ to 6″
  • Radishes: 2″ to 3″
  • Rutabagas: 8″
  • Turnips: 2″ to 4″

Remove Seedlings

Select the seedlings you don’t want. Grip the seedling between your forefinger and thumb. Give a gentle tug, and it should come out without disrupting the garden bed much.

Remember, this method of seedling removal is best when the soil is moist. Now, if you’d rather not disrupt the soil and other seedlings, use the scissors or snips to cut the seedling at ground level.

Optional Thin by Raking

If your growth is in blocks instead of rows, get your flexible rake and run it through the seedlings and thin what you don’t want. Raking works best if your seedlings are perfectly spaced. But raking can free up room and is faster and less tedious than manual cutting or plucking.

Finish Off With a Refreshing Rinse

Not for you. It’s a good idea to mist the remaining seedlings to rejuvenate the plants. 

Add a natural fertilizer rather than chemicals. Chemical fertilizers burn the tender root of seedlings. Good options are liquid form (kelp is good), compost used tea bags, or organic fish emulsion.

Final Thoughts

If you worry about wasting vegetable plants, there’s good news. Some tiny seedlings, including beets, spinach, lettuce, and chard, can go in recipes and salads. The entire process of thinning seedlings is natural and eco-friendly, especially when you can eat the leftovers!

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