Beginners Guide: How to Prune Tomato Plants for Maximum Yield

The main aim of planting tomatoes is to get the maximum yields possible. You may want to remove the unnecessary suckers and leaves for the plant to maximize the use of nutrients towards productions of fruits

Selectively removing unwanted plant growth from indeterminate tomatoes can help to improve production and the taste of the harvested fruits. Further, removing a set of older leaves improves air circulation and keeps the plant off the ground. This reduces the chances of fungal diseases like early blight and septoria leaf spots attacking.

Does Pruning Tomatoes Increase Yield?

Yes, pruning tomatoes increases yields. It helps the plant to direct its energy towards fruit production rather than the production of foliage. Pruned plants tend to produce larger fruits as compared to those left alone. 

Pests and disease attacks are among the common causes of poor yields in tomatoes. Pruning ensures the plant receives free air circulation and stays off the ground. Tomatoes are at risk of fungal infections like early blight and septoria leaf spots if they are lying low on the ground. 

In addition, when plant leaves stay permanently in shade, they produce less sugar. This can be corrected by pruning or staking the plant to remain in an upright position. This ensures all the leaves receive adequate sunlight. Plants use sunlight in the process of photosynthesis to manufacture their own food.

How to Prune Tomato Plants for Maximum Yield

The main reason why you may want to prune your tomatoes is to help the plant to direct its energy and nutrients towards fruit production. However, before picking that pruning shears, it is important to figure out the following:

The tomato variety you are growing

There are two main types of tomato varieties, i.e., indeterminate and determinate. The common indeterminate varieties include Beef Master, Big Boy, Black Prince, and German Queen. Most cherry and heirloom tomato varieties belong to this category.  

On the other hand, determinate varieties are Amelia, Better Bush, Ace 55, Biltmore, Patio, Mountain Pride, Heinz Classic, and Headmaster. 

Indeterminate tomato varieties grow like vines and require a lot of staking and pruning to keep them upright, while determinate varieties require less or no pruning and staking. They can contain themselves and direct their energy toward fruit production. 

Readiness of your plants for pruning

The common mistake that many gardeners make is pruning their tomatoes too late. Watching out for the following tell-tale signs will help to guide you on whether your plants are ready for pruning or not:

• Check for yellowing of lower leaves

Yellowing of the first set of leaves is among the early signs that a tomato plant is ready for pruning. It is an indication that the plant no longer needs them. You can start to prune when you notice this change in leaf color.

• Check for sprouting of suckers

Suckers are small new branches that emerge at the center of the leaves and branches of indeterminate tomato plants. They are the branches that you would want to remove. When left to grow, they can produce fruits but will compete for nutrients and other resources with the main plant. 

• Check for flowers

The plant is mature when you start to observe the appearance of flowers. At this point, you can go ahead and start pruning. During flowering, the plant requires a lot of energy. Cutting off the suckers and older leaves can help the plant to stay healthy and produce larger fruits.

The techniques to use for pruning

The quality and quantity of fruits to get from tomato plants are determined by the techniques you use during the pruning process. Be gentle when removing the suckers and older leaves to minimize injuries to the plant. Here is how it is done:

1. Prune all the suckers below the first cluster of flowers

Removing all the suckers below the first cluster of flowers is one way of ensuring that the nutrients are directed toward the development of the fruits. When the plant is left alone, the nutrients may be wasted on the unwanted suckers.

To remove the sucker, grab it at the base using your thumb and forefinger. Bend it back and forth until it plucks away. This procedure should be done when the sucker is still young to prevent serious injuries to the plant.

2. Do not prune thicker suckers

Snapping off thicker suckers can cause serious injuries to the plant. Use a Missouri pruning method on suckers that are thicker than a pencil. This method is done by pinching the tip of the sucker. Leave behind a set of leaves for photosynthesis and protection of the fruits from a sunscald.

3. Remove the lower yellow leaves

It is normal for the lower set of leaves to turn yellow as the plant matures. However, you should remove them once you start to notice a color change. Yellow leaves use more energy from the plant than they produce. They can also act as pest and disease transportation media.

4. Remove some fruit-bearing tissues from the indeterminate tomato variety

When all the fruit-bearing tissue is left to develop, there may be a competition for nutrients and other resources. The fruits will be many, but too small. For larger and healthier fruits, you can remove some clusters of fruit-bearing tissues.

5. Top the plant

Remove the terminal shoot when the fall of frost is around the corner or when the plant hits the ceiling of your greenhouse. The plant will use its nutrients for the development of the fruits instead of supporting further growth.

What are the Advantages of Pruning Tomatoes?

When tomato plants are left on their own without pruning, they can grow shrubby or into a jungle. The weight of the foliage and fruits can also cause the plant to topple. The plant can be attacked by pests and diseases when the leaves and fruits come into contact with the soil. 

Pruning helps to keep the plant healthy and is advantageous in the following ways:

1. Earlier tomato fruit ripening

Tomato suckers are new plants that grow between the main stem and each leaf. Requires a lot of energy from the main plant to grow. When removed, the plant directs the energy towards fruit production and earlier ripening.

2. Ease of harvesting

Pruning tomato plants makes it easy to harvest the fruits. Ripe tomatoes are visible and easy to access without interference from the neighboring plants. Imagine how it would be difficult to walk through a jungle of tomatoes looking for ripe tomatoes. 

3. Larger fruits

Reducing foliage content means that the plant will be able to put more energy towards fruit production. When suckers are allowed to grow, they may produce more clusters of fruits but small in size. Fruits require a lot of energy to develop. Too many of them will compete for nutrients.

4. Reduced pest attack

Most gardeners agree that pruning tomatoes can help to reduce pest infestations. Shrubby tomato plants provide ample hiding places for pests. Old leaves at the base of the plant can also act as a transportation media of pests like hornworms. They crawl on the plant and attack leaves, stems, and fruits. 

5. Minimize diseases

Tomato plants are prone to different fungal infections, such as early blight and septoria leaf spots. They thrive well in areas that are warm, wet, and have poor air circulation. Unpruned tomato plants provide ideal conditions for the multiplication of fungal infections.

6. Increased sunlight on leaves

Plants use sunlight to produce energy through the process of photosynthesis. Pruning allows all the leaves to be exposed to the sun. It is difficult for the lower leaves to receive sunlight when the plant is shrubby.

7. Improved fruit quality

Adequate sunlight encourages tomato fruits to develop sugars and ripen faster. If you are staying in a cooler climate area with short seasons, pruning can help to speed up fruit ripening. However, do not over-prune plants if you live in hotter climate areas. Over-exposing fruits to the sun can cause sunscalds in tomato fruits.

8. Increased plant vigor

Pruning improves the general health of the plant. The plant receives increased air flow that prevents bacterial and fungal pathogen infections. The soil is less liable to splash on a pruned plant. There are also fewer chances of leaf spots on pruned plants since the leaves stay drier most of the time.

9. Encourages space utilization

If you have limited gardening space, pruning can help to enhance planting more crops in the same amount of space. With pruning and well management, you can decrease the plant spacing from the recommended 24 inches between the rows to 18 inches and still receive high yields.

Tomato Pruning Mistakes People Make

There are some pruning mistakes that many gardeners make that end up costing them their effort. They include:

1. Pruning determinate tomato varieties

The limitations of pruning determinate tomatoes outweigh the advantages. Pruning won’t affect the quality or quantity of the harvested fruits. Apart from causing injuries to the plant, cutting the suckers simply means that you will get fewer fruits. 

If it is a must to prune determinate tomatoes, don’t cut the suckers. Remove a set of yellow leaves at the base of the plant that may be touching the ground

2. Pruning excess foliage

The plant requires enough leaves to provide itself with energy through the process of photosynthesis. Removing too many leaves can cause stress to the plant. The leaves also act as a shade to protect the fruits from a sunscald.

Over-pruning, especially during summer weather conditions, can damage the fruits.

3. Pruning too late

When growing indeterminate tomato varieties, it is detrimental to prune late when the plant has already established itself. Cutting thick suckers may cause injuries that allow in bacterial infections.

The main aim of pruning is to keep the plant leaves off the ground, maintain an upright posture, and maximize the use of nutrients. Late pruning may not give positive results as it would have been done earlier.

4. Using unsterilized tools

Dirty and unsterilized tools can introduce bacterial or fungal infections to your plants. Clean the tools properly using a disinfectant or clean soapy water. To avoid the spread of diseases, do not use the same shears to cut old diseased leaves and the young suckers. 

5. Pruning wet plants

Tomato plants are prone to fungal infections. Pruning when the leaves are wet can encourage the spread of diseases from infected plants to others. Be sure to wait until the plant is completely dry.

Final Thoughts 

Pruning indeterminate tomatoes promotes maximum yields by ensuring there is maximum utilization of sunlight and nutrients. A healthy plant equals high production, pruning ensures the plant is less attacked by pests and diseases.

 On the other hand, determinate tomatoes do not require pruning, the plants can contain themselves and direct their energy naturally towards fruit production without further interventions.