Tomato Seedlings Growing Very Slowly

Most farmers, especially beginners, have to deal with the stunted growth of crops. It’s obvious that after planting tomatoes and nurturing them, you expect them to thrive and yield a great harvest. 

Sometimes, though, they don’t progress as expected. It’s devastating, to say the least, especially if you can’t tell the causes of tomato seedlings growing very slowly. 

The leading causes of the slow growth of tomato seedlings include extreme temperatures, improper watering, and lack of sufficient nutrients. Therefore, you should plant the seeds in warm temperatures and healthy soil. In addition, ensure you regularly water your young plants for optimal growth

This article discusses the causes and appropriate solutions to the problems you may experience with the seedlings. Additionally, you get to learn how to prevent it from happening in the first place. 

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Why Are My Tomato Seedlings Growing Very Slowly?

There are several causes as to why your tomato seedlings are growing very slowly. Below are some of the causes and the solutions. 

Extreme Temperatures 

Extreme temperatures, whether too hot or too cold, can slow the growth of your seedlings. Midsummer high temperatures are ideal for growing seedlings. They require 70 degrees to develop well. However, if the temperature rises above 100 degrees or below 40 degrees, the seedlings stop growing. 

Unfortunately, you can’t control the weather. Even so, using a garden cloche can protect your seedlings from the cold. A cloche is a glass cover or clear plastic that you can use to protect your young plants from cold, pests, and wind. 

Likewise, you can’t stop a heat wave. Nonetheless, you can put mulch on your soil to help control the temperature by insulation. Also, use a shade cloth that lowers the heat reaching your plants by several degrees. If the weather becomes hotter and drier, it’s advisable to water your seedlings several times during the day. 

Improper Watering

Watering helps tomato seeds sprout. Once they do, they require regular watering to ensure they grow well and fast. However, some seeds may experience moisture deficiency, making the seedling stop developing. 

Even though the seedlings require water, they hate soggy soil. Therefore, ensure your soil drains any excess water fast, so it doesn’t remain soggy for a long time. If the soil stays wet for long, you’ll find there’s no room for air. Thus, your seedlings’ roots can’t breathe, encouraging rotting and eventually killing off the young plant altogether. 

Most beginners are too generous when watering the young ones and end up killing

them. Work with mother nature to avoid this. If it’s most likely to rain, don’t water your seedlings and wait for the rains instead. 

Do also reduce the amount of water you use if you notice the weather becoming cooler and damp. Why? Because the water evaporates more slowly in this kind of weather. 

Nutrient Deficiencies

The typical nutrient deficiencies that affect tomato seedlings are potassium and phosphorus. In rare cases, you might realize your soil lacks magnesium and manganese. 

A lack of sufficient phosphorus slows down the growth of the seedlings. Additionally, the young plants put less energy into their roots. As a result, they’ll use a lot of water which then interferes with their development. 

Likewise, if there’s a lack of nitrogen, the seedlings use a lot of energy to grow and don’t develop as fast. 

The best solution is to get a nitrogen, potassium, and phosphorus fertilizer. In addition, you can also add compost to the soil as it adds nutrients.

How Can I Make My Tomato Seedlings Grow Faster?

You can make your tomatoes seedlings grow faster by doing the following 6 things:

  1. Choose A Fast Maturing Tomato Variety

You can plant a quick grower tomato variety known to develop in less time than usual. When purchasing the seeds, check the seller’s description that indicates the time the plants take to grow.

  1. Warm Up The Soil

Tomatoes need warm soil to develop well. Chilly ground slows down the growth of seedlings. Therefore, it’s advisable to warm the soil before you plant the tomato. How do you warm the soil? You pull back mulch in early spring to expose the ground to the direct sun’s warmth. Additionally, you can place a transparent plastic sheet over your garden bed. 

It’s essential to note soil in raised gardens and containers warms up faster because of the extended height. Thus, they’re ideal for planting your tomatoes. 

  1. Harden Off Seedlings 

It’s advisable to harden the young plants to acclimate them to the outdoor weather conditions. Better still, you can place a mini-greenhouse on each tomato seedling for protection as they adjust.  

Gradually introduce them to the outside by taking them out for several minutes a day before transplantation. 

  1. Protect Seedlings From Wind And Chill

Wind dries out young plants and may cause the still fragile stems to break. Therefore, planting your tomatoes on the house’s south side is advisable to protect the seedlings from strong winds. Also, it’s less chilly there. 

  1. Wait To Apply Mulch

It would be best to leave the soil bare around new seedling transplants for about a month. This allows the sun to keep warming the ground. 

However, once the summer sets in, apply a 2-inch layer of straw mulch to help maintain the soil moisture.  

How Do You Fix Stunted Tomato Seedlings?

You can try adding a 2-inch layer of old compost to the soil around the seedlings. Additionally, you can apply fertilizer like a bone meal and repeat it 3 and 6 weeks later. It’ll help to restore the nutrients the seedlings require.  

During applications, ensure you don’t spill any fertilizer on the leaves. Also, water the tomato seedlings well after the application. 

If the cause of the stunted growth is pests and diseases, take proper measures to control them. You can look up the suspected disease or pest in a pest database. It’ll guide you on what you need to get from the agro vet and the best way to tackle the disease. 

Additionally, it’s advisable to water your seedlings with tap water instead of stored rainwater. The reason being the water may be harboring bacteria and fungi.

Also, allow the water to drain before you water the seedling the next time. The soil should feel moist when you touch it. You can change the soil to a better draining medium or aerate it to improve the drainage. 

Stunted tomato seedlings regain their vigor once you deal with the factors affecting their growth. The new leaves sprout afresh in about 3 to 4 weeks. 

If the young one’s growth stunt is due to fungal or viral infections, the probability of recovery is minimal. Unfortunately, by the time you discover the diseases, it’s usually too late, and damage has already happened. 

Why Are My Seedlings Staying Small

The following may be the reasons why your seedlings are staying small:

Too Little Water

Undoubtedly, if your seedlings are getting too little water, they’ll not grow tall and mature to be able to bear fruits. Therefore, you should check if the soil is dry. If so, water the seedlings, and let them soak up as much water as possible. 

Nevertheless, be careful. Don’t overwater the seedlings as their roots may rot, destroying the entire plant.

Lack Of Nutrients

If your seedlings lack phosphorus, they’re most likely to remain small as it helps make plants grow tall. To take care of this, apply a fertilizer with phosphorus such as blood meal to the soil mix. 

Temperatures That Are Too Cold

When the temperatures fall below 13 degrees Celsius, your tomato plants experience difficulty in producing enough energy required for growth. Thus, they stay small without growing, which may happen when you plant too early in the season. 

To avoid this, plan to plant your tomatoes at the right time, depending on the previous frost dates. Nevertheless, if you have to plant early, start them off in a greenhouse or pots inside your home where the temperatures are conducive.

Then, after the frost has passed, you can transplant them outside to the garden beds. 

Temperatures That Are Too Hot

When the temperatures go up to 30 degrees Celsius or higher, it can hinder the seedlings’ growth. Therefore, you can move the seedlings to a place with a bit of shade. 


How Fast Should Tomato Seedlings Grow?

It takes about 6-8 weeks from sowing the tomato seeds to transplanting the seedlings. Check the last spring frost date and count back 8 weeks. That’s when you should sow the seeds indoors. Otherwise, you’ll have overgrown seedlings if you plant too early. 

Wrapping Up

I believe that the reasons for tomato seedlings growing very slowly are now clear.  But just to wrap up, some of them include a lack of nutrients or improper watering. Also, it could be the variety you chose to plant is a slow grower. 

Thanks to the simple remedies discussed above, for example, you can add fertilizer or compost to add nutrients to the soil. You can also go for a fast-growing variety that takes less time to develop. Additionally, be keen when watering the seedling. 

Ensure your seedlings grow in the ideal conditions and enjoy a bountiful harvest of big juicy tomatoes.