Leggy Tomato Plants: 3 Common Culprits [And How to Fix Them]

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If you’re starting your seedlings for the first time, you might run into some common, but easy to fix, tomato growing problems. If you’re starting your garden indoors over the winter, you might run into the common issue of leggy tomato plants.

There is so much excitement for me in watching seeds germinate and grow into fruit and vegetable producing plants. I’ve always been amazed by the science of it and think it’s just magical.

I distinctly remember the elementary school text books introducing plant life cycles and always thought of them as fascinating. Luckily, I still feel this way. Which is why it’s especially sad to see a plant not growing quite as well as it should.

Unfortunately, I am also battling leggy tomato plants and am trying to nurse it back to health. Here’s what you can do to get that plant back into shape.

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Identify the Leggy Tomato Plant Issues

There are usually only a few culprits guilt of causing a leggy, spindly plant. Let’s identify them one by one and suggest tips to nurse leggy tomato plants back to health.

Culprit #1

Lack of sun. When did you start your seedlings? Was it too early before the last frost? Has it gotten adequate light? Tomato plants especially need more than 8 hours of direct sunlight a day to grow appropriately.

If they are not receiving enough sunlight they will ‘stretch’ to reach it. This also causes them to bend or curve in one direction. That direction is where the sunlight is. Can you save it? It’s tough, but not impossible.

Fix #1

Re-pot the plant and bury them deep, up to the bottom most sprouted leaf on the stem. Provide a large enough pot to allow roots to grow. If it’s not warm enough for the plant to live outside in direct sunlight, you will need a grow light.

A windowsill won’t be enough. Allow them to soak up the sun during daylight hours if it’s warm enough, otherwise get that artificial light. Aim for 8-10 hours a day for a strong tomato plant. If it’s gotten warm enough outside, transplant them into the ground into a deep trench.

Bury them over the bottom few leaves of the stem and plant them is a sun soaked area.

Fix #2

Perhaps you don’t yet have enough access to lots of pure sunlight that will allow for the plant to thrive, and maybe it’s too cold to put them outside. If that’s the case, your next best option is to purchase a grow light.

Luckily, you can easily find them, especially online. You should look for T5 fluorescent lights, which will be the best for your in-door garden and help those spindly tomato plants beef up. They are also the most cost efficient.

When shopping for your perfect indoor grow light, you’ll need to factor in the color of the light. There are cool blue shades of light as well as warm red shades, each serving their own purpose.

Cool colored lights encourage leafy vegetative growth, whereas warm colors encourage fruiting and flowering. While warm colors seem to be your answer to solving your leggy tomato plants problem, you’ll actually need both!

Either use two grow lights, one with each shade of light, or use a grow light that needs multiple bulbs and place half cool and half warm into the unit.

fixing spindly tomato plant seedlings

Culprit #2

Insufficient water. Baby plants are thirsty! You need to make sure you are watering them thoroughly or else you will end up with thin, stringy, leggy tomato plants.

If they were planted in the ground, you would make sure you water them everyday, right? You need to the same indoors. Plants need water to grow.

Fix #1

If you find the soil is drying out too quickly between waterings, put them in a larger pot with more soil to keep them hydrated. You should also use an irrigation system to provide burst of water throughout the day if you’re in an arid, hot climate.

Water them regularly or once you notice the top layer of soil is dry to the touch or turns a bit of a gray color. Check to make sure your soil is not too sandy or drains too quickly. Use a quality soil that will retain moisture.

If your natural soil is not up to par, you’ll want to purchase an all-purpose garden soil that will help those skinny tomato plants thrive. To boost your growth, add a manure, and add mulch to the top most layer of your soil.

The mulch will retain moisture and release it slowly, helping to keep you vegetables well fed.

Fix #2

The soil is too compact for the air and water to reach the roots in the best way. Remember, when watering, you want to water the roots, not leaves. If you find that the soil looks compacted or flat, aerate the soil.

This is the technique of loosening up the soil enough to allow additional moisture, air, and sun into the soil, reaching the roots and allowing for positive growth. Try not to poke the roots of any of the vegetables and avoid damaging them, but do a thorough enough fluffing to see an impact.

Fix leggy tomato plant

Culprit #3

Overcrowding. Here’s where things went wrong for me. I thought it would be a fun and cute project for me and my 4 year old son to plant seeds together. So when handfuls of seeds landed in the grow pods, there was not much I could do except hope for the best.

What happens is the that the plants are competing for nutrients, water and sun. They are depriving each other of the necessary ingredients for survival resulting in long thin stretches of tomato plant stems

Fix #1

Don’t let your 4 year old sow the seeds! Ahem, not speaking from experience or anything…

If four year olds aren’t your issue, and you notice a big clump of seedlings growing together, thin the seedlings out a bit to avoid them competing for nutrients. You should have 2-3 stems per pod.

Once you start seeing thick, stocky stems, you’re good to go. This is a sign of a strong plant that can withstand the weight of a heavier fruit and that you have successfully saved your leggy, spindly, tomato plant seedlings.

Now that you’re on the road to thick, beautiful tomato plants, make sure you know how and when to prune tomato plants once they start growing!

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