How To Prevent Leggy Seedlings

Leggy seedlings are a sign that you are not starting your seeds correctly. Here are some tips to prevent leggy seedlings for good!

If you are just getting into starting your own seedlings you have probably heard the term leggy. I bet your wondering what leggy seedlings are and why they need to be prevented.

What Are Leggy Seedlings

Leggy seedlings look like they are stretching and they often have long stems with few leaves. There is usually one long stem that starts at the soil and reaches all the way to the first set of leaves.

These seedlings also have weak stems that will cause them to flop over. Make sure to not mistake leggy seedlings with damping off though.

Why Are Leggy Seedlings Bad

Leggy seedlings are not as sturdy and can be broken easily. They also waste a lot of energy growing stems instead of lush leaves.

Seedlings that are leggy are also more prone to pest, disease, and fungal issues like damping off. These seedlings are not ideal, but they can be salvaged and used in the garden.

The best thing to do is prevent leggy seedlings so you don’t have to deal with the problems that come along with them.

To prevent leggy seedlings we first need to understand why seedlings become leggy.

Causes Of Leggy Seedlings

Here is a list of all the things that can cause leggy seedlings. Usually the number one culprit is low light, but there are other things that can cause leggy seedlings.

• Low light
• Over watering or under watering
• Mal-nutrition (not enough fertilizer)
• Improper temperatures
• To many seedlings in a pot
• No air movement

How To Prevent Leggy Seedlings

To prevent leggy seedlings you basically need to take the list above and just reverse it. Here is what seedlings need to not become leggy

• Lots of light
• Correct amount of moisture
• Plenty of nutrients
• Mild temperatures
• Good spacing
• Air movement

Here is each one of these necessary preventions broken down into specifics.

Lots of Light

I have found that inadequate light is the number one reason seedlings become leggy. Not using a grow light, or not using it correctly, causes seedlings to stretch while they search for more light.

You DEFINETLY need to be using a grow light for your seedlings. The sunlight coming through a window is not strong enough to grow healthy seedlings.

Use a grow light and position it a few inches above your seedlings. You never want your lights more than 3-5 inches away from the lights.

Keep the lights on a timer and make sure they run for a minimum of 13 hours. I like using this timer and it makes everything effortless.

Finally make sure you are using a good grow light. Here is a great post on how to find a good grow light for seedlings.

Water Correctly

Honestly, it takes a bit of experience to water seedlings enough but not too much. It will become easier the more you start plants, but here are some good guidelines.

Always keep the soil completely moist when germinating seeds. You can use a humidity dome and I love to use a mister to keep the soil evenly moist.

Once your seedlings germinate remove the humidity dome and quit spraying them with water. Keeping them too moist after germination is a recipe for fungal issues.

Use the bottom watering technique, and water once you notice the top layer of soil is getting dry. It is always important that the soil looks a bit dry before you water it.

Use Good Soil Or Fertilize

High quality potting soil can make a huge difference in your plant’s health and it can prevent leggy seedlings.

I recommend mixing up a recipe of my DIY potting soil. I have had the healthiest seedlings using this recipe and I have not gone back to bagged soil mixes.

My recipe is full of nutrients, and I don’t have to fertilize my seedlings because the soil mix has enough nutrients in it!

Use a heat mat correctly

Too often people leave their heat mats on after the seedlings emerge from the soil. Heat mats are only supposed to be used for sprouting seedlings.

Here is a full post on the correct way to use a heat mat when growing seedlings.

Don’t overcrowd your plants

Overcrowding plants in a pot can cause leggy seedlings because all the seedlings are competing for nutrients and light.

Use a fan for air circulation

In nature, plants are constantly being moved by the wind and animals brushing up against them. This disturbance signals the plants to grow sturdy stems.

You can use a fan for your seedlings and set it on low to mimic wind. The constant air movement will help your seedlings to grow sturdy stems.

You can also just brush the tops of your seedlings daily to help them grow healthy roots and stems!

How to salvage a leggy seedling

I say salvage because once a seedling becomes leggy there is only so much you can do. The good news is that plants like tomatoes can be salvaged better than some plants can.

Here are a few things you can do to salvage already leggy seedlings.

Pot Up

I start my tomatoes plants in smaller cells and then move them on to larger pots to help them stay short and healthy.

If you have any of your seedlings that are getting leggy simply move them to a larger pot and bury the stem deeper. It is important to wait until your seedlings have a healthy root system before potting them up.

Correct Issues

To stop your seedlings from getting leggier you should correct any of the issues I listed above. Move your grow lights closer to the plants, turn off your heat mat, etc.

Plant Deep

Once it is time to plant your leggy seedlings you can plant them deeply in the soil. This is great for tomato plants as they grow new roots out of the stem.

You can also plant tomatoes in a trench if you do not want to dig a deep hole.

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