One of the first things I look forward to after a long winter is starting seeds for my gardens. I love to jump-start my growing season early! Until I see leggy seedlings. Let’s talk about how to prevent and fix them!

This post contains affiliate links. For more information, see our disclosures here.

I absolutely love starting seeds indoors. It not only saves me a lot of money, but I can start growing things earlier in the year and tend to my seedlings.

I also find that I can grow plants and flowers that I don’t often see at my local greenhouse. But as with anything else, it requires some knowledge and a little trial and error to be successful.

Today I’m sharing this trial and error with you regarding leggy seedlings and how to fix them. Let’s grow pretty things!

1. They aren’t getting enough light

7 ways to truly prevent leggy seedlings they aren't getting enough light
These seedlings have perfect light with the grow light above them.

This is perhaps the #1 reason that seedlings get lean, pale, and leggy… insufficient light.

Your seedlings get leggy because they are reaching for the much-needed light that they aren’t getting.

Having a seed tray sit on a sunny window is just not enough light, especially in the late-winter/early-spring season.

A new seedling requires 8 solid hours of sleep. This means no nightlights or the light from a late-night reader.

The remaining 16 hours should mimic a full sunny day.

If you are going to start growing seeds indoors, then you need at least one grow light.

The one I use most often is my Two-Tier Lighting Cart from Burpee. It’s an investment that has definitely paid off over the last few years!

I also completely love the three tabletop grow lights I have. All you need with these grow lights is a desk or table you aren’t using, and there you have your own growing station.

If you have the light too high up, it will again cause your seedlings to reach for it, making them become leggy.

I place my lights directly over the tallest seedling, literally almost touching it. And no, it doesn’t burn my leaves. It does prevent leggy seedlings, though!

PRO TIP: Place your grow lights on a timer, so you never forget to turn it on or off!

2. Lack of air movement

7 ways to truly prevent leggy seedlings lack of air movement
Photo courtesy of Fred Merchan

When seeds are started outside, they grow up healthy. You’ll seldom see leggy seedlings outside, and this is mostly because the seedling is exposed to the elements. Mainly, the wind.

A seedling exposed to the wind gets strengthened from the inside and learns to stand against it naturally. Think of the wind as a natural workout for your plant!

A seedling started indoors can be way too pampered without wind, thus leading to long legs. And this isn’t a good trait for a seedling!

How can I mimic the wind for my indoor seedlings?

You can mimic the wind by having an oscillating fan gently blowing your seedlings all day long. It’ll be most beneficial to have the fan (very gently) running 24 hours a day. At least keep it on while you’re awake.

You can even plug your fan into your timer, so you never have to think about it.

This will strengthen your seedling and prepare it for the outside world. And prevent legginess.

I’ve put older seedlings outside without giving them the fan treatment, and those poor plants took an absolute beating from the wind. So you’ll want to do this! It really does make the difference.

3. They’re getting too dry

7 ways to truly prevent leggy seedlings they're getting too dry
Photo courtesy of Ewen Roberts

Seedlings like to grow in evenly moist, high-quality soil. Letting them dry out too much will cause leggy seedlings.

Dry soil causes the seedlings to not get the nutrients they need, and of course, soil that is too wet will simply kill them.

So then, how often do I water seedlings?

Since they are usually in a small growing tray, they can dry out quickly. This usually means watering the seedlings once a day, possibly more (or less). A good way to water is to spray them with a water bottle to keep the soil moist.

I will usually put water in the bottom of the tray and let them suck the water up. The excess gets poured out. Doing this will also train the roots to grow deep instead of shallowly to reach the water.

PRO TIP: Once they have their first set of true leaves, you don’t have to water as often.

True leaves are usually the 2nd set of leaves you see on the seedling. These are the leaves that actually perform photosynthesis for the plant.

4. They’re getting too much fertilizer

7 ways to truly prevent leggy seedlings they're getting too much fertilizer
Some seedlings on the floor were fed too much fertilizer.

A seedling given too much fertilizer will sprout up very quickly, causing leggy seedlings. The problem is too much nitrogen.

This issue usually isn’t in the soil, but in the well-meaning gardener.

It’s important to know that the seedling gets all the nutrients it needs from the seed and the first set of leaves, called cotyledons, so it does not need fertilizer right away.

So when to feed seedlings?

Once the SECOND set of true leaves appear. Important to note, this is NOT the second set of leaves, but second set of TRUE leaves.

You can then start feeding a diluted mixture of your choice of quality, all-purpose, water-soluble fertilizer. I usually will use Miracle-Grow, unless someone gives me some seaweed fertilizer or something to try.

To dilute, I mix half of what the manufacturer recommends and feed 1-2 a week. This will prevent leggy seedlings.

You can continue this feeding until they go into the ground, or switch to full strength once they start growing more, and feed every 7-10 days.

5. They’re overcrowded

7 ways to truly prevent leggy seedlings they're overcrowded
Photo courtesy of Derek Bridges

When I plant my seeds, I stick with putting one seed per cell. I can then see which seeds aren’t viable, and I don’t have to worry about overcrowding.

When seedlings get overcrowded, they get shaded from each other. They then try to outgrow their companion by reaching for the light.

This gives us leggy seedlings.

If you must put more than one seed in a cell, try planting them on opposite sides or use a bigger pot. Or, since sometimes it’s impossible to drop one tiny seed into a cell, transplant them carefully into their own pot as they grow.

PRO TIP: Use a fingernail or end of something pointy to plant one seed at a time. This gives you better control.

6. Overheating

7 ways to truly prevent leggy seedlings they're overheating

It’s February or March, and you’re worried about your new seedlings getting too cold.

So you do what any good gardener would do, you leave them on the heat mat.

Too much heat is actually a leading cause of leggy seedlings.

A heat mat is perfect for getting seeds to sprout, and some actually require the heat, but once you see the seedling, take it off the mat.

If your room is too cold, try putting your seedlings in a warmer area or use a small space heater.

Most likely, your seedlings are okay, though, as they usually don’t stop growing until it gets below 50°.

Make sure you move the seedling off the mat and out from under the dome or plastic wrap as soon as you see it sprouting up.

7. How to fix them

7 ways to truly prevent leggy seedlings how to fix them

So you’re reading this article after you already have leggy seedlings, now what? Can they be saved?

You may be able to save them if you apply all of the tips above quickly.

Ensure they are getting sufficient light, aren’t crowded or dry, aren’t being fed too much, and have air movement.

I’ve saved many leggy seedlings just by doing these things. They will always remain slightly leggy, even as adults, but once they are big, beautiful, and outside, it’s not noticeable.

Other than fixing any issue they may have, there’s not much else you can do except learn from any mistakes.

Some people will just throw them away and start over, but I honestly can’t do that. If something is trying to grow, I will give it every chance possible to do just that.

Even if I have to stick them in the back of the garden or something. I make sure the leggy seedlings get their chance. 🙂

PRO TIP: Plants with adventitious roots, like tomatoes, can be planted outside up to the lowest set of leaves.

Adventitious roots are proto-roots growing out of the stem’s sides that can grow with the right conditions. If any of you have any indoor Pothos plants, you may be familiar with what this is.

leggy seedlings adventitious root example from pothos plant
Aventitious root on Pothos plant

When do I give up on leggy seedlings?

If you don’t mind throwing them away, I would say that when the stems get super thin and weak, and most of it is lying on the soil, it is a good indicator.

Again I’ve just let these grow and placed them in a protected, out of the way area in my yard somewhere. I just can’t bear to toss them for a mistake I’ve made.

The choice is yours. To prevent leggy seedlings in the future, though, just follow these tips, and I can guarantee healthier happier seedlings!

What are some of your favorite plants to start from seeds? Any other questions? Please leave a comment below! Thank you! 🙂

Leave a Reply