Leggy Tomato Seedlings – (Causes and SOLUTION)

If you’ve ever grown tomatoes from seed, you’ve probably seen the dreaded leggy tomato seedlings at one point or another.

One thing to note is that, it is not only tomatoes that tend to have spindly seedlings when the conditions are not right for the germinating seeds.

Other vegetables and herbs such as pepper, mint, kale, zucchini, basil etc. also do sometimes have leggy seedling.

Every vegetable gardener at some point have experienced spindly tomato plants.

In this article, we will talk about how to identify leggy tomato seedlings, what causes them and how to how to prevent or fix leggy tomato seedlings, so you can ensure the healthy growth of your plants.

Leggy Tomato Seedlings vs. Normal Tomato Seedlings

Leggy Tomato Seedlings

When comparing leggy tomato seedlings, also known as etiolated seedlings, to their healthier counterparts, distinct traits emerge that set them apart. The term “leggy” characterizes the elongation of the stem, resulting in a frail and spindly appearance. Contributing factors to the development of leggy tomato seedlings include insufficient light, improper spacing, and excessively high temperatures.

Characteristics of Leggy Tomato Seedlings

1. Long and Fragile Stems
Leggy tomato seedlings often showcase elongated stems with noticeable gaps between leaves. The stems may appear fragile, struggling to adequately support the weight of the plant.

2. Sparse Foliage
Inadequate light results in sparse foliage, with leaves spread out along the stem. This can impede the tomato plant’s ability to effectively undergo photosynthesis.

3. Reduced Vigor
Leggy tomato seedlings generally exhibit diminished vigor compared to their well-developed counterparts. Weakened defenses may render them more susceptible to pests and diseases.

Normal Tomato Seedlings

In contrast, normal tomato seedlings epitomize healthy growth and vitality, flourishing under optimal conditions with the right balance of light, nutrients, and spacing.

Characteristics of Normal Tomato Seedlings

1. Compact and Robust Structure
Unlike leggy tomato seedlings, normal tomato seedlings boast a compact and robust structure, featuring well-developed stems capable of supporting the weight of the plant. Uniform spacing between leaves contributes to a balanced appearance.

2. Abundant Foliage
Healthy tomato seedlings showcase lush and abundant foliage, indicating robust growth and efficient photosynthesis. This abundance of leaves enhances the tomato plant’s capacity to produce energy and nutrients.

3. Vibrant and Resilient
Normal tomato seedlings display a vibrant green color and a resilient overall appearance. Their increased resistance to environmental stressors positions them for successful growth, promising a bountiful tomato harvest in various gardening conditions. In essence, the distinctions between leggy tomato seedlings and normal tomato seedlings highlight the critical importance of providing optimal conditions for healthy and vigorous tomato plant development.

How to identify legginess in tomato seedlings.

It is very simple to identify a leggy seedlings. All you need to tell that you have at your hand leggy tomato seedlings is that the stem looks stretchy. 

This results in the seedlings growing tall very fast as the seedling is trying to reach out for light source. 

Leggy tomato seedlings also have thin stems. This is because the seedling focuses its attention and strength on searching for sunlight or light and not much on growing thick and firm stems. 

You can also identify spindly tomato plants by observing that the seedlings look to be bending over after some time.

All these signs are clear indications that you have leggy seedlings on hand which needs to be dealt with. So the next question that naturally follows is what causes leggy tomato seedlings. 

What Are The Causes Of Leggy Tomato Seedlings

Leggy tomato seedlings are definitely signs that you are not doing something right. There are things that causes tomatoes seedlings to become leggy.

These include not exposing your germinating seeds to the right amount of light throughout the day. Also, starting a lot of seeds in the same space leading to overcrowding.

Too much heat can also lead too your germinating seeds to become leggy. Inconsistent soil moisture is a culprit that can equally lead to leggy tomato plants.

Lack of Adequate Light For Germinating Seeds 

Seeds need nutrient rich, moist soil or potting mix as well as adequate light (natural light – sunlight; the better) to germinate well.

Plants depend on the presence of sunlight to undergo photosynthesis in order to prepare its food that will aid its growth. Plants require not less than 12 hours in a day.

No or limited exposure to light will result in the seedlings growing tall and bending towards the direction of your source of light.

Once this phenomenon is identified, you should know that your seedlings are growing leggy and need to be attended to as quickly as possible.

Excessive Fertilizer Can Result in Leggy Tomato Plants

Another common cause of leggy seedlings is adding too much fertilizer. Seedlings require low amounts of fertilizer.

The adage “too much of everything is bad”, though not entirely true however certainly applies to too much fertilizer application to your plants. 

Too much fertilizer can also result in your seedlings growing leggy and fast but producing only foliage and lots leaves at the end of the day without proper fruiting.

Overcrowding of Tomato Seedlings

One mistake beginner gardeners make is overcrowding seeds in seed trays when starting their seedlings.

Overcrowded seedlings will result in some overshadowing others that will result in those tomato seedlings becoming leggy as they will try desperately to get sunlight.

Leggy Tomato Seedlings As A result of Poor Ventilation

Stems of tomato seedlings will grow strong, thick and sturdy when they are exposed to some amount airflow or wind. 

Without proper ventilation among your seedlings, your tomato seedlings will grow up weak and might suffer shock during transplanting.

How To Fix Leggy Tomato Seedlings. 

No one is interested in spending time and resources in starting seedlings which turn out to be leggy and eventually die or result in stunted growth along the way.

Can you save leggy tomato seedlings? Yes of course. Leggy tomato seedings is not a death sentence for your plants as when identified early, they can be saved and the next few paragraphs will show how to fix your leggy tomato plants.

To fix your leggy tomato seedlings problem, expose seedlings to right amount of sunlight or light, check your drainage, add organic matter or fertilizer to the soil if the soil lacks the right nutrients for your tomato seedlings, control the temperature and repot. 

Unless you are able to tell the exact reason for your tomato seedlings becoming leggy, try one fix at a time so you are able to tell the exact cause of the problem. But preferably, start with exposing your tomato seedlings the right amount of light first. 

Increase the amount of exposure to light

The foremost reason why you will have leggy tomato seedlings is that your tomato plants or seedlings are searching for light.

If you are growing in an open space, make sure that where your seedlings are has fair amount of sunlight during the day. Tomato seedlings need a great amount of exposure to sunlight or light so ensure that they are well exposed to it.

Avoid starting your tomato seedlings in areas where there are shades the greater part of the day that prevents sunlight from reaching your seedlings.

If you are growing indoors, ensure your grow light provides sufficient light to your tomato plants or tomato seedlings to prevent legginess in the tomato plants.

You may need to get a brighter source of light when starting your seedlings indoors or bring your light source a little closer to the seedlings to give them adequate light so they don’t grow leggy and tall.

However note that too much of exposure can also lead to your seedlings dying. 

Repot Leggy Tomato Plants 

When you have too many seedlings in one grow tray resulting in leggy plants or you have a leggy seedling, you can save that seedling by repotting them.

You can do so by burying the stem of the leggy plants or seedlings very deep in the soil of the new container up to the lowest sets of leaves.

If the seedlings are due for transplanting, you should bury the stems in the ground or your plant’s container up to the lowest set of leaves also referred to as cotyledon leaves.

Ensure however that the leaves do not touch the soil as it may result in the leaves picking up diseases that may damage your plant in the long run. 

Planting your seedlings deep in the soil will prevent the stem from breaking when wind blows and also the part of the stems buried will start growing extra roots that will aid the plant to become more sturdy.

Tact is required in removing and repotting your leggy tomato seedlings. You visit The Seed Collection website and read the well spelt out steps in fixing your leggy seedlings.

Test the Drainage

If your seed starting soil does not retain the right amount of water or retain too much water,  it will result in your seedlings being under stress because the soil will be dried the most part of the day.

At the early stage of your seeds germinating into seedlings this is not a good condition for your seedlings. Ensure that there is some moisture in the soil. 

Sometimes the best way to retain moisture in your soil if you will not be available in the house throughout the day is to apply mulch around the stem of your plants.

There is the need for the moisture in your soil to be consistent throughout the period the seeds germinate till the time of finally transplanting. 

You should develop a routine for watering your seedlings and try as much as possible to follow through everyday. 

There are smart gadget that can assist you to know when your seedlings need to be watered. If you want to have a smart garden, and also have the resource to afford, you can make good use of same.

However, as a beginner in gardening, your eyes and your timing should be enough to tell when the soil looks dry and needs watering.

You should also have a journal where you keep record of the progress of your seedlings. You can get a journal by visiting https://amazon.com and searching for gardening journal. 

You should however avoid over watering the seedlings at it may result in dampness and resultant rotting roots, disease to plants and ultimately death of your seedlings.

Add Some Fertilizer or Organic Matter

Your germinating seeds need nutrients to be available in the soil for you to have strong seedlings and plants. A good pot mix soil will be sufficient to use for starting your seeds into seedlings. 

If you are adding fertilizer to your soil because the soil lacks the right nutrients the seedlings need to grow well, ensure you do not add too much fertilizer. This is because, over fertilization of your seedlings can cause more damage to your plants.

It is best to use a diluted liquid fertilizer for your seedlings. In other instances, you will need to add some organic matter to your potting soil.

Adding organic matter to your soil is another way to improve the growth of your leggy seedlings. Instead of purchasing pre-made amendments, you can easily make your own by mixing in manure or compost.

This will improve the soil texture and provide your plants with nutrients and minerals they need to grow. This can be done by adding a little bit of the amendments to your soil or by mixing it in with your soil when you re-pot your plants.

Good organic amendments for garden soils include wood by-products such as sawdust and bark mulch, peat moss, rotted manure, grass or wheat straw and compost.

Control the temperature

As a general rule, you want to keep your tomato plants in their optimal environment. Low temperatures prevent leggy tomato seedling growth by slowing the metabolism and preventing the cells from growing and dividing.

It is advisable that temperatures should be between 65°F to 80°F to reduce the chances of leggy tomato seedling formation because high temperatures equal high levels of heat and moisture in the soil, which can lead to leggy tomato seedlings.

Allow Proper Air Circulation

Prevent your tomato seedlings from forming leggy stems by providing adequate air circulation among your seedlings so they can grow strong stems. You can turn on a fan that blows air on the seedlings to get them to experience the conditions that pertain outside so that your tomato seedlings will be able to withstand when transplanting is finally done in the garden beds outside.

Final Words

So there you have it. Lack of adequate light, high temperature, over-fertilization, poor soil drainage, and overcrowding of seedlings can cause leggy tomato seedlings.

Expose the affected seedlings to adequate light, separate seedlings into individual pots if they are overcrowded in the seed starting tray, add fertilizer or some organic matter when needed or necessary and don’t forget to keep an eye on your plants.



If you are starting eggplant, cucumber, pepper, and other vegetables and their plants are leggy, you can read about their fixes below.

Fixes For Other Leggy Vegetable Seedlings

If you have other vegetable seedlings in your garden that are becoming leggy such as pepper seedlings, tomato seedlings, etc. these resources below are a great read.

  1. Leggy Cucumber Seedlings – (100% QUICK Solutions)
  2. Leggy Pepper Plants (Causes and 6 Easy FIXES)
  3. Leggy Swede Seedlings (QUICK Solutions)

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