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Don’t Restart Your Leggy Seedlings. Try THIS First!
Leggy seedlings are a common problem for gardeners, especially when starting seeds indoors. If your young plants are tall, thin, and weak, they may struggle to develop into strong, productive plants. Luckily, you can actually fix leggy seedlings and prevent the issue in the future. In this guide, we’ll cover why seedlings become leggy, how to correct the problem, and what to do to ensure sturdy plants.
How to Fix Leggy Seedlings
Lots of gardeners get leggy seedlings when they start their vegetables indoors. And they try to fix it by restarting their seedlings.
But the problem is that if you don’t know what’s causing it, then it will just happen again.
So instead of restarting all of your leggy seedlings, I’m going to show you exactly what you can do to fix them and prevent it from happening again.
So let’s get right into how to fix your leggy seedlings!
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What are Leggy Seedlings?
“Leggy” is an extremely advanced gardening term for a seedling that looks overly stretched out and weak. When the stem is really long compared to the size of the leaves, then it looks like the seedling has long legs.
That’s why we call them leggy.
Leggy seedlings are usually really tall but only have a couple sets of leaves. For example, a 6 inch tall tomato seedling might normally have about 4-5 sets of leaves. If you have leggy tomato seedlings, then they’ll only have about 2 sets of leaves.
To learn more, check out my article on 11 common seedling problems and how to fix them.
Why are Leggy Seedlings Bad?
Leggy seedlings are bad because they’re really weak. When the stem gets so long but there’s only a few leaves, then you know that those plants are not strong.
This becomes a problem when transplanting and they’re exposed to the outdoor conditions. The wind and sunlight will kill your weak seedlings, leaving you with nothing to plant.
Understanding Phototropism
Now, I know, we’re getting a little bit technical, but it’s important!
Phototropism sounds like a complicated word, but it really just refers to the growth of a plant in response to light.
Plant cells are incredibly advanced in their functions and can respond to changes in lighting conditions. You’ll really notice this if you start your seedlings indoors without using grow lights.
Most people who do this usually place the seedlings by a sunny window. Over time, the seedlings will naturally turn towards the sunlight. This suggests that plants can, in some way, detect light.
That’s phototropism: the ability for plants to detect light. Keep that in mind.
What Makes Seedlings Leggy (And How to Fix it)
If you notice that your seedlings are leggy, then don’t worry, there might still be time to save them.
While you can just restart them, this might not be the best option. When you restart all your seedlings, you’re getting rid of at least a couple of weeks of the time you spent.
So don’t jump straight to restarting them, try these tricks instead.
Fix Your Lighting
This is by far the most common cause of leggy seedlings: improper lighting conditions.
For those of you who don’t use grow lights, firstly you should get some LED grow lights. But of course, you don’t have to.
If you’re using a sunny window, then the best thing to do is turn your seedlings every couple of days. Once you first start noticing them leaning towards the light, then you need to turn them 180°.
Don’t wait until the tops of the seedlings have fully bent over like their back is broken. Turn them right at the first sign of leaning.
If you wait too long, then they’ll lean and lean and lean, until they are fully stretched out.
Additionally, the seedlings should be getting 6-8 hours of direct light at the bare minimum. If they get considerably less than this, then they’ll start to get leggy in search of light.
You have more control over this if you’re using grow lights. And you can even leave the grow lights on for 12-14 hours every day (which is what I do), giving them more light to photosynthesize and grow quicker.
But even then, you might still be wondering, “why are my seedlings leggy with a grow light?”
In that case, it usually happens if your lights are too far from your seedlings.
If they’re too far, then the seedlings will stretch out to get closer to the light. Remember phototropism?
This can be fixed easily by moving the lights closer. They should be maximum 2 inches away from the tops of your seedlings. As they grow, you gradually move them higher.
You can also have problems if your lights are too dim. If your grow lights are really old, then you should buy some new bulbs and replace them. LED bulbs are the way to go with grow lights.
Thin Out Your Seedlings
When we sow our seeds, we often put multiple seeds in one seedling cell. I normally put 2 seeds for a fresh seed packet, and about 5-6 for old seeds.
Of course, this guarantees that at least one seed will germinate. But what happens if all of the seeds germinate? We can’t let them all grow in the same hole.
This is when they get overcrowded and start competing for resources, one of them being light. They will compete for light by stretching out in front of each other to try to reach the light source.
Seriously, it’s like people trying to get in front of you in a race. And they’ll even block out each other by growing on top of the others.
This causes the seedlings to become leggy. But we can prevent it.
Once the seedlings grow one set of true leaves, then you need to start thinning them. Thinning is basically just removing the weakest and smallest seedlings to allow only one to grow fully.
Firstly, identify which seedling is the strongest and largest; that’s the one you want to keep.
Then remove all of the other seedlings by cutting them at the base. Don’t pull them out unless you want to repot them into new seedling cells.
If you pull them out aggressively, you might disturb the roots of the seedling that you want to keep. So just cut them off at the base.
This will allow the strongest and healthiest seedling to continue growing, eventually producing some food for you.
Use Less Fertilizer
When plants get lots of nutrients, they have to use it somehow to grow. But if the plants are really small, then it’s hard for them to properly allocate all the nutrients.
This makes the plants grow very quickly and produce leggy stems because there’s nowhere else for the nutrients to go. It all goes into the plant’s stem and the few leaves that it has.
And the problem is that the seed contains all the nutrients the seedling needs until they develop their first set of true leaves.
So you need to wait to fertilize your seedlings until they develop their first set of true leaves. After the seed leaves and first true leaves grow, then you can start fertilizing.
But you should use a very weak fertilizer with a low NPK ratio. This organic fish emulsion fertilizer is perfect, as it has an NPK ratio of 2-3-1.
Young seedlings don’t need a lot of fertilizer, they’re really tiny. You can dilute the fertilizer to about half the recommended strength and it’ll still be fine.
Fertilize the seedlings every week with a liquid organic fertilizer, slowly increasing the amount of fertilizer as they get larger.
Maybe It’s Too Hot
If you’re using a heat mat to help your seedlings to germinate, then it might be causing some problems with your seedlings.
Yes, they do help some seeds to germinate, and I love using heat mats for my seedlings as well. But once they germinate, there’s no need to keep the heat mat there.
And it can become problematic if it gets really hot. Heat signals the plants to grow larger and faster, which leads to leggy stems.
To prevent this from happening, just remove the heat mat once the seeds germinate. Once you first see the seeds start to pop through the soil, take them off the heat mat and move them under some light.
Use a Fan
You see, inside your house is nothing compared to the conditions outside. There’s lots of wind outside, which helps to strengthen the stems.
We can stimulate this by placing an oscillating fan in front of your seedlings. I have one where I can adjust the speed and put a timer on. I usually do about 3-4 hours every day.
This helps to stimulate the outdoor conditions by creating wind, which strengthens the stems. They won’t even have a chance to be leggy because then they’ll just break. Instead, they’ll produce strong and stocky stems that are resistant to the wind.
Can Leggy Seedlings be Planted Deeper?
Some plants can actually develop roots along their stems, which are known as adventitious roots. So if you plant the stems deeper into the soil, roots will develop along the stem.
Tomatoes, peppers, eggplants, and cucumbers all have the ability to produce roots on their stems. This means that if you have leggy tomato, pepper, eggplant, or cucumber seedlings, then you can just plant the stems deeper and they won’t be leggy anymore.
They’ll develop more roots along their stems and get a stronger and stockier stem.
But don’t try this with every plant. Most vegetables can’t develop adventitious roots, meaning the stems will just rot if you bury them with more soil.
Can You Top Your Seedlings?
Topping is when you cut off the growing tip of your plant, allowing it to produce side branches and bush out.
This really only works with a few varieties, namely peppers and determinate tomatoes. But even then, young and small seedlings might die if they’re topped.
Most of the time, leggy seedlings are only a few inches tall, with only 1 or 2 sets of true leaves. If you top them when they’re this small, then they probably won’t survive much longer.
So it’s best to avoid topping leggy seedlings.
How to Fix Leggy Broccoli Seedlings
You might be wondering why I dedicated an entire section to fixing leggy broccoli seedlings.
For some reason, all of my brassica (broccoli, cauliflower, turnips) seedlings always become leggy. I have no idea why. Do you ever experience this? Maybe it’s just me, I don’t know.
I try putting the light so close to the soil, but it just doesn’t work.
The best thing that I found, even though it doesn’t work extremely well, is to bury the seeds deeper when you’re sowing your brassicas.
Maybe If the seeds are deeper, then the stems will have space to stretch out in the soil before sprouting. That’s how I think of it.
I’m still testing this method, but they seem to be a little bit less leggy when I do it.
You Might Have to Restart Them
I know, I said that you shouldn’t restart your seedlings because it takes off at least 2 weeks of your work.
But sometimes, leggy seedlings get so bad that your only option is to restart them. It’s better to plant out healthy transplants that are a little bit younger, than to plant leggy transplants that will probably die outside.
If you’re for sure that your seedlings are too leggy and you can’t save them, then don’t hesitate to restart them as soon as possible.
I know it takes off a few weeks of your precious time, but if it’s the last option, then you have to do it.
Frequently Asked Questions
Can you get leggy seedlings outdoors?
If you’re sowing your seedlings in a well-lighted area, then they shouldn’t be leggy. If you’re planting your seeds in shade, then they will stretch out to try to find the light. But generally, the wind and intense light make it so that leggy seedlings are almost impossible.
Which seedlings get the most leggy?
All seedlings have the ability to be leggy, but I have experienced that brassicas are the worst when it comes to this. Almost every brassica seedling turns out leggy, no matter what I do to prevent it.
How close should grow lights be to seedlings?
Your grow lights should always be about 2 inches away from your seedlings. As they start to grow larger, gradually move them away, always keeping the 2 inch distance.
Even More Gardening Ideas
Here are a few more posts to get the ball rolling in your garden!
- How to Grow Cucumbers from Seed to Harvest
- Planting Bare Root Raspberries in Spring
- 10 Climbing Cucumbers Varieties to Grow on a Trellis
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