Growing plants in your garden is an enjoyable experience but sometimes the plant stems grow tall and spindly. This makes the plant weak and it may even fall under its own weight.
You can get thicker stems on your plants by providing them with the required amount of sunlight, water, aeration, nitrogen, and space. The most common reason your plants don’t grow thick stems is due to a lack of sunlight. You need to learn about your plant requirements to grow them better.
I’ve written all the details that will help you figure out what is the problem and what you can do to get thicker stems on your plants. Below is the list of things to do to get thicker stems on plants.
- Provide the plant with sufficient sunlight
- Provide sufficient growing space
- Make sure the plant is getting enough nitrogen
- How To Get Thicker Stems (And Keep Your Plants Healthy)
- Ensure good aeration in the soil
- Give the plant enough water
Many times the simplest way to get thicker stems on the plant is to provide it good amount of nitrogen-rich fertilizer. You can add this once every month so the plant gets the required nutrients. Check out the best nitrogen fertilizer on Amazon.com.
Provide the plant with sufficient sunlight
If your plant does not get the required amount of sunlight, it will grow tall and spindly. The plant tries to reach out and get as much light as it can that causes this problem.
But you can’t just place your plant in direct sunlight. You need to learn more about your plant and understand how much sunlight it needs.
Some plants need full sun which means at least 6-8 hours every day. Other plants need to grow in partial or full shade.
Once you know how much sunlight your plant needs, you need to place it in a suitable location in your garden. If the plant needs full sun, make sure there are no obstacles like a wall or tall plants blocking the light.
If the plant needs partial shade, the places with partial obstructions like tall plants or fences would make a good growing space.
If you’re already growing the plant, you can trim the branches of tall plants blocking sunlight. Or you need to move the plant to another location in your garden.
If your plant needs more shade, you can try placing a sunblock or any type of tall object that will obstruct the direct sunlight.
Provide sufficient growing space
If your plants do not get sufficient growing space, they will compete with each other for nutrients, moisture, and sunlight.
The foliage of the plants will block each other and prevent sunlight from reaching. This means the plant won’t be able to produce food efficiently. They will grow weak and spindly as a result.
The lack of sunlight and airflow among the foliage will create a humid condition that will encourage fungal diseases. This will stress the plant further and make them weak.
The lack of growing space among the plant roots means they will compete for nutrients and moisture from the soil. The lack of nutrition will make the stems grow thin.
I suggest that you should understand more about the plant you are growing. You need to find out how much growing space the plant will need. Then ensure you give the plant that much space in your garden.
If you’regrowing the plant in a container, I recommend only growing one plant if the container is small. If it’s large, you may be able to grow a few of them.
If the plants are already growing in the garden and are lacking space, you need to take a few of them out and transplant them to another location.
Make sure the plant is getting enough nitrogen
The plant you are growing needs nutrients just like humans. The macronutrients that are important for the plant are N-P-K, Nitrogen, Phosphorus, and Potassium.
If you want your plant to have a thicker stem, the most important macronutrient is nitrogen. This encourages foliage and stem growth.
I like to usecompostin the soil as it provides organic matter and nutrients to the roots of the plant. It also introduces beneficial organisms that further increase the nutrients in the soil.
If you don’t have compost, the other option is to add an organic fertilizer to the soil in your garden. You can choose a balanced fertilizer with an N-P-K of 5-5-5. Or you can choose one that is nitrogen-rich such as one having an N-P-K of 10-5-5.
Some examples of nitrogen-rich materials are blood meal, bone meal, alfalfa meal, and seaweed.

It’s important that you read the manufacturer’s instructions before adding the nitrogen to your garden soil. It will tell you how much to use and how often.
If you use too much nitrogen in your soil, it will burn the roots of your plant. This will have the opposite effect that the plant will not be able to get nutrients. And the stem will grow thin and weak.
Ensure good aeration in the soil
If the soil is not suitable for the plant you’re growing, the stem will be weak and thin. You need to learn about the plant and provide it the required soil.
Your plant will need oxygen from the soil so it can produce food and transport nutrients through the foliage.
If the soil has a good texture, it will have air pockets from which the roots can get the required oxygen.
If the soil contains a lot of clay, it will clump together and reduce these air pockets so the roots get less oxygen. If the soil contains a lot of sand, there will be good aeration but the soil will drain water too fast.
You want the soil to contain the right amount of organic matter to strike a balance. Then it will have the right texture to retain enough moisture but allow good aeration as well.
My favorite material to improve the soil for plants is to add organic compost. This material improves the texture as well as introduces beneficial organisms to the soil. That helps improve your garden soil even further.
You can get a soil test conducted on some samples of your garden soil. Your local extension service will help you with this test for a nominal fee. They will also inform you of the amendments you can add to improve the soil.
Give the plant enough water
Your plants need water to grow well. The amount of water they need and how often will depend on the plant you’re growing.
Hardy plants need less water or need less frequent watering. Other plants will need more water and often. You should understand your plant’s needs before you start to grow them.
If the plant gets too little or too much water it can get stressed and grow weak which means thin stems.
If the plant you’re growing is hardy, you should water less often. Let the soil completely dry out before you water it again.
If the plant needs plenty of moisture, you need to keep the soil moist every day. The moment you see the surface of the soil is dry, you can water it again.
If your plant gets more water than required, it can get stressed out. A hardy plant will not prefer to grow in soil that is moist all the time.
The other problem that can happen isoverwatering. This is a common issue if the drainage in the soil is not good enough.
The water collects near the base of the plant roots and drowns them causing root rot. The roots become black and soggy. They are unable to provide the plant with the nutrients causing the plant to become weak.
The easiest way to figure out the moisture content of the soil is to use a moisture meter that you stick into it.
The other good option is to just stick your finger 1-2 inches into the soil. When you take your finger out check if the soil is sticking to it. If not, it means the soil has dried out and you need to consider watering it. again.
If the plant is suffering from root rot, you need to take it out of the ground and cut off the affected roots. Then you can replant it in another location of your garden that has good drainage.
Here are some of my favorite container gardening tools
Thank you for reading this post. I hope it helps you with your gardening needs. I’ve listed some tools below that can help you with container gardening. These are affiliate links so I’ll earn a commission if you use them.
Gardening Gloves – I find the Pine Tree Tools Bamboo Gardening Gloves really good for both men and women. It’s made from bamboo so helps absorb perspiration. They are also comfortable and fit very well.
Containers – You know picking the right container is crucial for your container gardening. I’ve written a detailed post on the best containers you can choose from. If you’re happy with a plastic container, you can check out the Bloem Saturn Planter.
Watering Can – This is a must-have tool when you’re growing plants in pots or grow bags. It helps to water the potting soil without splashing on the foliage. The Kensington Watering Can is stylish, strong, and can provide precision when watering potted plants.
Trowel – Garden Guru Trowel is my favorite because it’s durable and comfortable to use. My gardening friends really love having a trowel because they use it for digging soil, mixing fertilizer, moving seeds, leveling out the soil, mixing compost or mulch, and also dividing tubers
Bypass Pruner – I really like the Corona Bypass Pruner because it’s durable and gives a clean cut that helps plants recover faster. If you’re looking for something cheap, get the Fiskars Bypass Pruner that is really good as well.
To see an extensive list of the best container gardening tools gardeners recommend, check out this resource that I made for you.
FAQs
How To Get Thicker Stems (And Keep Your Plants Healthy)? ›
Potassium helps plants make strong stems and keep growing fast. It's also used to help fight disease.
How do you make a plant stem thicker? ›- Give them space. Plants need a lot of space to grow. ...
- Pay attention to the temperature. ...
- Provide proper nitrogen. ...
- Ensure proper air circulation. ...
- Trim weak branches. ...
- Provide a proper amount of light. ...
- Boost humidity. ...
- Use a good-quality soil.
Potassium helps plants make strong stems and keep growing fast. It's also used to help fight disease.
Why are my plant stems not thickening? ›Plants need sunlight to grow, so if they're not getting enough light, their stems will be thin and weak. Next, consider fertilizing your plants. A good fertilizer will provide your plants with the nutrients they need to grow strong and healthy. You can also try pinching the top of the stem.
Why are my plant stems thin? ›The stems grow thin because the plant is desperately reaching its leaves towards the light. Seeds that are started late winter or early spring, when the sun is still low in the sky, are prone to this type of growth pattern.
What fertilizer is needed for stem strength? ›Nitrogen promotes green, leafy growth. Phosphorus encourages flowering and root growth, and potassium is necessary for stem strength and stress tolerance. Secondary nutrients that are required in slightly lesser quantities include calcium, magnesium and sulfur.
What growth makes stems wider? ›Meristems contribute to both primary (taller/longer) and secondary (wider) growth: Primary growth is controlled by root apical meristems or shoot apical meristems. Secondary growth is controlled by the two lateral meristems, called the vascular cambium and the cork cambium.
What causes weak stems? ›Not enough light
“Legginess” in seedlings is caused by low light, as plants stretch to reach a light source. Eventually, this will result in weak stems, and the plant will struggle to support itself. If you have a sunnier window, consider moving your plants there. Otherwise, you may need to include artificial lights.
The xylem distributes water and dissolved minerals upward through the plant, from the roots to the leaves. The phloem carries food downward from the leaves to the roots. Xylem cells constitute the major part of a mature woody stem or root.
What stimulates the growth of stems and leaves? ›Gibberellins (GAs) stimulate shoot elongation, seed germination, and fruit and flower maturation; GAs are synthesized in the root and stem apical meristems, young leaves, and seed embryos.
What increases the thickness of roots and stems? ›
In botany, secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate, and gives rise to primary tissue.
How do you revive a plant stem? ›Start by trimming all the dead parts first. Do the same with the stems, one bit at a time, until you see signs of green. If the stems are completely dead but the roots are still intact, leave bits - about 5 cm - of stem intact above the soil. When your plant revives, the new stems will sprout from these old stems.
How do plants with weak stems grow? ›Complete answer: Creepers are plants that have weak stems and can not stand upright. Creepers are also known as prostate or sub-aerial weak stems. They grow by spreading stems and branches on the ground (sometimes water), new plants develop from the nodes of the branches and stems.
What encourages root growth? ›The two main nutrients that support excellent root growth in plants are phosphorous and potassium. These two ingredients are extremely helpful in any fertilizer mix that needs to encourage a thick, healthy collection of brand-new roots, or to strengthen and stimulate existing systems.
How do you fix lean plants? ›Fortunately, there's a simple fix for this: just rotate it. When a plant is leaning, it's telling us that it's exhausted from using all that energy to grow in one direction. That's why it's essential that you rotate your houseplants every once in a while to make sure that their auxin gets evenly distributed.
How do you support a weak plant stem? ›There are several ways to accomplish this kind of staking. You can use a simple purchased wire cage that surrounds the plant, or you can use several stakes with twine strung between them to form a support system.
How do you fix leggy stems? ›Trimming, pinching, and pruning are all helpful activities for eliminating leggy growth. Start by pruning back the longest stem. You can cut right above the uppermost growth node, which should encourage the plant to create new growth at the side of the stem rather than continuously upward at the top.