How to Get Thick Stems on Tomato Plants – Practical Tips you can implement NOW!

Are your tomato seedlings becoming stretched and spindly? Worried you will end up with broken stems from plants that can’t support themselves?

Follow our comprehensive guide to how to get thick stems on tomato plants. Produce strong, healthy tomato plants with bumper crops of delicious tomatoes.

How to Get Thick Stems on Tomato Plants

Welcome to today’s feature article at the Garden Bench Top, where we dive into our favorite tips for growing thicker and stronger tomato plants.

Practical Tips for Thicker Stems on Tomato Plants

Below is a list of our most practical tips for growing thick stems on tomato plants. We recommend reading through all the tips in this guide, before deciding to take action.

Rather than trying one tip at a time, try implementing a few tips at the same time. This will give you the best chance for success, and help you achieve stronger tomato plants.

Tip 1 – Give them a Head Start

tomato plant cotyledon leaves
credit: redditramblings

One of our favorite tips for encouraging strong growth is giving your tomato plants a power boost right at the beginning of their lives.

As soon as you see the cotyledon leaves of the tomato seeds peak out from the soil, we give them an energy boost with a 72-hour period of non-stop light. This provides the seedlings with the necessary light (and energy) to establish a healthy root system. A stronger root system lays the foundation for higher nutrient uptake by the plant. That then results in stronger, thicker tomato stems.

Note, as you can appreciate, this tip will only work if you are planning on growing your tomato plants from seeds. Applying this tip to mature seedlings will have a detrimental impact on their health, since plants require intervals of no light to recuperate from a busy period of growth.

Tip 2 – Let there be light.

Light is important for strong thick tomato plant stems

A lack of light is one of the primary causes of irregular growth in plants.

Plants require light to fuel their growth. Light is especially important during the seedlings’ stages of growth. Without it, they will not have the necessary energy to form a healthy and strong foundation for future growth.

It is so important, in fact, plants will search for the best sources of light. If there is insufficient light, they will reach for the light by growing taller, sideways and even around objects blocking their path, just to reach some light.

And it is for this very reason that tomato plants can form weak and thin stems.

To ensure your tomato plants develop thick stems, ensure they have sufficient light.

Provide adequate light sources for your tomato plants to ensure strong thick stems

If you are growing your tomato plants under lights, make sure the lights are low enough to discourage your tomato plants from stretching up. We recommend keeping the lights 3-4 inches (7-10 centimeters) above the tomato plants at all times. This means, adjusting the lights’ height as your tomatoes grow.

TIP 3 – Three’s a Crowd

Okay, before you go out and cull your tomato crops, this tip doesn’t have anything to do with the number ‘three’ per se. You can most definitely keep more than three tomato plants at a time. We are simply using it to demonstrate that overcrowding your tomato plants can cause them to grow thin stems.

credit: giphy

Overcrowding your tomato plants and seedlings can have the same effect as not providing enough light. As the plants mature, they begin to shoot out leaves which can block the light of other plants.

As a result, they begin to grow in abnormal directions to reach the light. Resulting in poor stem formation and weak plants.

To prevent this from occurring, ensure you leave enough space between your tomato plants. This applies to when you plant them in the ground, as well as when you are rearing the seedlings in seedling trays.

Tip 4 – Water is Life

Providing a constant and adequate water source for your tomato plants will ensure the formation of healthy, thick stems.

If your plants currently rely on your diligence and meticulous watering schedule for their source of water, we would recommend installing an irrigation system to drip feed water.

Don’t get us wrong, we are not questioning the rigor of your watering schedule. But life happens. Who knows what is going to happen tomorrow, next week or the following month.

Even a short dry period can have long – term detrimental effects on your tomato plant crop, resulting in thin stems and weakened plants.

For us, the added peace of mind justifies the small expense. Why risk it? When you can systemize your plants’ water source using an automatic watering system.


just because you have the water on automatic, doesn’t mean you should stop visiting your tomato plants. Be sure to inspect them regularly for any issues, like pests. It also gives you the opportunity to make sure the irrigation system is functioning as it should.

Tip 5 – Feed Feed Feed

feeding tomato plants with nutrients is key

Making sure your tomato plants receive the necessary nutrients and minerals to grow is imperative for healthy plants with thick stems.

You will need to supply three primary elements in order for your tomato plants to get thick stems: phosphorus, nitrogen and potassium.

The best way to deliver these nutrients to your plant is by adding fertilizer to the soil. All-purpose fertilizers are generally readily available at your local nursery. We recommend picking a slow-release fertilizer, which is designed to slowly release the nutrients into the soil over an extended period of time.

Nitrogen, in particular, is a key ingredient for forming the best stems and foliage on tomato plants. To give your soil a nitrogen boost, use animal – based fertilizers like blood meal, bone meal or even composted manure.

Tip 6 – Support Your Plants

To give your plants the best chance of developing thick stems, provide them with support as they grow.

By attaching your plants to structured support, you will minimize the likelihood of broken tomato plant stems, from accidents like strong winds, or animals knocking over your plants.

Broken stems don’t necessarily mean game over for your tomato plants. But, it does hinder their growth and future productivity substantially.

Support structures like tomato cages or trellises are perfect for supporting your tomato plants.

Tip 7 – Mulch Your Plants

mulch tomato plants

Along with installing an automatic watering system, we recommend applying a layer of mulch to the soil around your tomato plants.

As mentioned earlier, providing a constant water source helps to develop stronger, healthier plants.

Not only does mulching help to retain moisture in the soil, it also helps to keep annoying weeds away and provides a cleaner, tidier garden.

Tip 8 – Pruning Your Plants

Pruning is a necessary skill that all gardeners must master at some point in their career. There are so many benefits to pruning your plants, like growing healthier plants and removing dead or diseased parts of a plant.

Or in this case, pruning your tomato plants helps to remove weight from the upper sections of the plant. Tomato plants are aggressive growers. In fact, they are probably too aggressive for their own good.

In an effort to absorb as much sunlight as possible, tomato plants can become quite top – heavy in foliage. Not only does this cause issues for the lower sections of the plant, it also creates problems with weight and the ability of the plants’ stem to support the plant – increasing a risk of a broken or bent stem.

Pruning back the leaves on the upper section of your tomato plant will relieve the weight issue. We also recommend pruning any branches that are close to the ground, which are susceptible to disease and mold.

Frequently Ask Questions

In this section we tackle all the odd questions that may crop up while you are trying to fix your tomato plants.

On a side note – if we don’t answer your question below, please reach out to us via our contact page and we;’ll be sure to respond as soon as we can. We’ll even feature your question in this FAQ section so other fellow gardeners can benefit.

Why are my Tomato Plant Stems Thin?

Growing tomatoes on thin spindly stems is like hanging your wet clothes on a paper streamer. It just doesn’t work, and will likely end in frustration and tears. Even if you manage to grow tomatoes, it is unlikely to produce many viable fruits for consumption.

So why does it happen?

A lack of light, water and malnutrition are the most common causes of thin tomato plant stems. We have listed our favorite tips (above) for growing stronger, thicker tomato stems. Simply follow these tips and you should be enjoying delicious home grown tomatoes within a few weeks.

How do I make my tomato plants bushier?

It may sound counter-intuitive, however constantly getting rid of your tomato plants leaves will actually produce a bushier plant.

Giving your tomato plant a hair cut early on in their growth phase will encourage the plant to shoot out new stems. Tomato plants are quick growers, so even though you may feel like you’ve taken too much off, within a week or two of hot weather, you’ll notice several new branches growing to replace the ones you have taken.

Just remember to provide a lot of water when they are growing.

What Causes Leggy Seedlings?

The most likely cause of leggy seedlings is a lack of light or your light is too high. We like to place grolights around 3-4 inches (7-10 centimeters) above the plants, and adjust as they grow.

If you are relying on sun to grow your seedlings, ensure they are placed on a window sill that receives plenty of sun during the day. This will enourage strong growth and give them the best start to life.

Can Spindly Tomato Plants Be Helped?

Spindly tomato plants are not ideal. But don’t give up on them just yet.

With the right love and attention, they may be salvagable. Provide your spindly tomato plants with some solid structures to support them as they grow. Provide them with the necessary nutrients (phosphorus, nitrogen and potassium) and supply plenty of water during their growth phase, and you can still come out with a healthy crop of tomatoes ready to be eaten.