It’s fun to enjoy tomatoes that you have grown in your own garden. But it can be frustrating when you find that your tomatoes are not growing as they should.

Your tomatoes are growing slowly because they are not getting the required sunlight to produce nutrients. Tomatoes need full sunlight which means you need to provide at least 6-8 hours of direct sunlight every day. You can clear obstructions like tree branches or move the plant to another location.

Several other reasons can cause your tomatoes to grow slowly and I’ve listed them below. I’ll also help you figure out what to do when your plant faces one of these issues.

Lack of Sunlight

If the tomato plant gets less sunlight than it needs, the tomatoes will not mature as fast as they should.

Plants need sunlight to grow. Tomato plants, in particular, will thrive in sunlight. The average variety needs at least six hours of sunlight per day to grow. However, eight or more hours will give you better results and more tomatoes.

Like any other plant, tomato plants take in the sunlight and convert it to energy. They need that energy to produce fruit, just like you need a cup of coffee in the morning to complete your job and activities for the day! The more sunlight they have, the faster and more productive the plant will grow. You should note, though, that tomatoes don’t need sunlight to ripen.

You should check the reason your tomato plant is not getting the required sunlight. If something is blocking the light such as tree branches or tall plants, you need to prune them.

If the problem is due to a wall or a fence, you’ll need to move the plant to another location that gets better sunlight.

Overwatering

Gardeners, both new and advanced, often overwater their plants. It’s a common cause of slow plant growth for tomatoes, even if the tomato plants are well-established. You might think that you’re doing your plants a favor by giving them plenty of water, but it can cause slow growth.

Soil saturated with water doesn’t provide any air circulation for the plants. Eventually, without air, the roots rot or aren’t able to absorb water anymore.

To avoid overwatering, make sure to check the weather for rain and don’t water when it rains. Additionally, water your plants less often with deeper soaks instead of watering them every day with little water.

I recommend checking the soil before you think about watering your tomato plant. Stick your finger 1-2 inches in the soil and feel the moisture. Only water the soil if the tip of your finger comes out dry.

If the plant is already suffering from overwatering, let the soil dry out and don’t water the plant till it recovers. Check the roots for signs of root rot. If that has affected the plant, you need to take it out of the soil and cut off the diseased roots.

Then transplant the tomato plant to another location in the garden with good soil that is dry and has good drainage.

Underwatering

The roots of a tomato plant grow a couple of feet down into the ground. They need enough water so that it reaches the ends of those roots. If you’re noticing that your plants have wilted leaves, yellow leaves, or dry soil, and they aren’t growing very fast or tall, then you might be underwatering them.

If you ever think your plants might not have enough water, you can check the soil. Use your fingers to poke through the soil and feel a couple of inches down. If it’s moist, don’t add water. But if it feels dry, you can add water.

If you don’t have the time to water the tomato plant or seem to forget, you can use drip irrigation or a soaker hose with a timer system.

You need to set it up once around your tomato plants. The system will slowly drip the required amount of water and make it available to the plant as and when it needs it.

Lack of Heat

When temperatures get colder, tomato plants cannot produce as much energy as when the temperature is warmer. Anything below 55 degrees Fahrenheit will slow down your plant’s growth.

It would be best if you kept tomato seeds at temperatures between 70 and 80 degrees Fahrenheit. Although you can’t control the weather conditions, you can help out your tomato plants.

You can protect seeds with a heating mat while they germinate. Younger tomatoes out in the garden will benefit from a cloche, which protects them from colder temperatures. 

Also, if you have more mature plants, you can use mulch or a row cover to protect them. If you start your plants inside, it’s good practice to keep them indoors until the risk of frost passes your region.

Make sure you’re growing the tomato plant when the temperatures are warm enough in your garden. Start growing the tomato plant outdoors a few weeks after the last frost date of your region.

Poor Soil Conditions

A healthy plant begins with healthy soil. Any slight change or imperfection in the soil where your plants are growing can result in slow-growing tomatoes. There are a few factors that can help your soil become perfect for your plants:

  • pH: Tomato plants prefer a slightly acidic pH of about 6.8, or even as low as 6.0. You can perform a soil test to know your soil’s pH or send in a sample to your local agricultural testing center.
  • Nutrients: Too many nutrients or not enough can also cause slow plant growth. Soil tests can help you understand what nutrients are lacking. And what nutrients are present in excess. 
  • Aeration: Tomato plants need good aeration in the soil. Compacted soil often occurs with overwatering or heavy rains. If you notice your soil is dense, use an aeration tool or a pitchfork to poke holes in the ground around the plants. This gives them room to breathe.
  • Mulching: Layers of mulch and/or compost can guard against moisture loss and prevent weeds from overtaking tomatoes. However, it’s recommended to limit mulch to a 3-inch layer to ensure plants can access enough oxygen.

Lack of Nutrients

A lack of nutrients can cause tomato plants to grow at a slow rate. An indicator of a deficiency in nutrients is usually yellow leaves. Just like with the pH, a soil test can tell you what your plants are lacking.

Often, one of the nutrients the soil lacks most is nitrogen. However, other nutrients may be lacking, including calcium, iron, phosphorus, potassium, and magnesium.

If you’re into composting, try adding nutrient-rich waste to your compost — organic matter from eggshells to tea leaves can add the missing ingredients and create a healthier environment for your tomatoes.

Of course, overcorrection can also be an issue. Be careful when adding nutrients that you don’t go over the limit, because too many nutrients can also cause stunted plant growth. Soil testing can help you keep tabs on your soil’s health and adjust your gardening to meet its needs.

Lack of Growing Space

Tomato plants need space. Depending on the variety, a tomato plant can grow anywhere from a couple of feet tall all the way up to 12 feet tall! They need plenty of room to grow, both horizontally and vertically.

When choosing your tomato plants, research their maturity levels and maximum height. Compromising on space will cause them to grow more slowly because they compete with each other for nutrients.

There will be a limited supply of nutrients, moisture, and oxygen for the tomato plant roots when they grow too close to each other.

Pests and Diseases

Pests and diseases may be holding your tomato plants back from their full potential. Common tomato pests include aphids, slugs, whiteflies, snails, tomato hornworms, and flea beetles.

Each pest has its own method of being removed, so if you notice any of these, do your research and avoid chemical pesticides when possible.

Your tomato plants can get infected with diseases such as blight, bacterial leaf-spot, damping-off, and various kinds of wilts.

The best way to prevent fungal diseases is to keep your tomato plants away from humid conditions. Avoid splashing water on the foliage. Make sure the plants are well-spaced and have plenty of airflow through the foliage.

If the plant is suffering from a disease, you need to prune the infected parts as soon as possible to help the plant recover.

If the tomato plant is suffering from a bacterial or viral infection, you can only slow down the problem but eventually, the plant will die and you need to dispose of it.

Transplant Shock

Another reason why your tomatoes are growing so slowly could be because of transplant shock. Most gardeners will start their tomato plants indoors from seed or purchase small tomato plants from a greenhouse. Those plants were once in constant warm, indoor air and plenty of light.

Transplanting them immediately to the colder, hard ground without acclimation to the outdoors shocks them, and therefore, their growth rate declines.

I recommend you harden the tomato plant or seedling before you move it to your garden outdoors. You need to keep the plant outside for a few hours every day. Make sure the plant stays out of direct sunlight, wind, or rain during this time. After a few hours, bring the tomato plant back indoors.

Keep doing this for a week and the tomato plant will have hardened to the outdoor conditions. You can now transplant it to your garden and it will not suffer from the stress of transplant as much.

Author:

Evelyn Long is a freelance writer and the editor-in-chief of Renovated. She publishes home improvement and gardening advice for homeowners at every experience level.