How To Prune Tomatoes For Maximum Yield (And Plant Health)

Growing tomatoes is one of the most rewarding crops to plant, nourish and tend. They’re highly nutritious and delicious to eat in salads or in raw form and work well in many cooked dishes, complementing other flavors.

The best thing is that tomatoes are relatively easy to care for.

They are happy in the ground or a pot as long as they have regular and consistent water, at least 8 hours of full sun a day, and plenty of nutrition throughout the season. 

And if you plant them early in the spring, under a warm cover, before planting out, you can enjoy their precious fruit all season long.

For tomatoes to produce a bumper yield,  there are several steps you can take, including regularly using fertilizer.

However, keeping on top of pruning is also one, and knowing why, how, and when to prune will keep fruits coming thick and fast. 

Why Prune Tomato Plants?

Whether or not you prune your tomato plants is a matter of opinion, and there is no hard evidence, either way, saying that it makes a difference to how your tomato plant performs.

However, many top gardeners swear by pruning, and with years of experience, their methods must have the truth.

If you allow your tomato plant to do its own thing, your plant will still create energy, and you will still have fruit.

However, if left to its own devices, the plant will direct energy to grow endless new shoots rather than to make tomatoes. 

You would also end up with a plant much bigger, and one that probably won’t fit the intended patch in your yard.

Pruning tomatoes will provide more space for the fruits to grow. It will allow more air to circulate and cutting back specific shoots will stimulate more flowers to grow, which, once pollinated, will begin to ripen. 

When To Prune Tomato Plants

Pruning and knowing how to prune is excellent, but knowing when to do it is just as important.

For best results, tomatoes are not the kind of plant you can leave and hope for the best. They need a certain level of care and a watchful eye.

Knowing when to prune is vital for the best tomato crop because it can be the difference between a triumphant yield and a failing crop.

Look out for these signs that your tomatoes need some attention.

It’s Growing New Shoots

At around 2-3 weeks after planting, and once your tomato plant begins to take off, think it’s time to think about a small-scale prune.

Your vines will grow exponentially at this point, and it might be worth directing the plant’s energy into one main shoot.

The Plant Becomes Overcrowded

You’ve left it a little too late when your vines begin to look like a bush, and some of the leaves are so squashed they’re rolling or wilting.

Although all is not lost, do get your secateurs to it and thin it out.

You Spot Yellowing Leaves

Yellowing leaves is never a good sign, and you’ll need to act quickly.

It is either a sign of disease, so whip them off and dispose of them responsible to stop the spread. Alternatively, your plant is suffering from a lack of nutrients.

Still, remove the yellowing leaves, but make sure you also top up the nutrients.

You Spot Brown Leaves

As with yellow leaves, brown leaves will always mean something is wrong with your plant, and it’s a good idea to remove them immediately.

In the best case, brown leaves mean your plant lacks nutrients, is wilting due to a lack of water, or has been scorched by the sun.

In the worst case, it is a sign your plant has blight, a fungal infection that will quickly spread and infect your entire crop.

The Plant Is Just Too Big

If you find your plant is just getting too big for your space, there is nothing wrong with cutting it back to control it for your designated area.

Luckily, tomato plants forgive when it comes to pruning, and you will not damage it by cutting it back. You may, however, lose some potential fruit.

How To Prune Tomato Plants (7 Steps)

1. Identify Your Tomato Variety

Knowing your variety is the key to successful pruning. There are two main types: indeterminate tomato plants and determinate tomato plants, and within these two categories are many types.

However, if you’re unsure: most people growing tomatoes will choose an indeterminate variety.

Indeterminate tomato plants are the ones that start small and grow into vines-like structures. They usually need support when they grow, and will usually need pruning to keep them under control.

Determinate tomato plants grow more like a bush. They do not need pruning, will only grow to their predetermined size, and bear fruit yearly with little to no intervention.

2. Wait For A Dry Day

The best time to prune your tomato plant, regardless of your variety, is early morning, when the weather is dry and your plant doesn’t have any water residue or droplets.

Pruning at this time is best because water is one of the main ways bacteria and diseases, such as blight, will spread and infect another plant. It also allows your plant’s wound to heal and stop infections from entering the plant.

When the weather and your plant are dry, the chances of reinfecting are much low, and you can pinch and snip without worrying about causing a problem.

3. Choose The Best Tools

A good, sharp pair of pruners or secateurs is great for cutting your tomato plant.

These garden tools are perfect for various plants, and it’s easy to use them repeatedly; however, it’s essential to make sure you clean them between uses.

Diseases and spores spread quickly, and a clean blade will help stop this.

4. Snip Back Suckers

Suckers are the new green shoots that grow in the ‘v’ between the main stem and the fruit-bearing branches. Many gardeners recommend snipping these off, but it does depend on your variety. 

For an indeterminate plant – those that grow like vines – this new growth will eventually become a new stem but does not serve a functional purpose for the fruit on your original stem.

Allowing it to grow will make your plant much more significant, heavier, and overcrowded. It would eventually give you more fruit, but it would be smaller.

Sticking to one main stem means more energy will go into those fruits, and they will end up being bigger, juicer, and tastier.

A determinate tomato plant is unlikely to need any pruning, and leaving suckers and new growth is fine because they will produce fruit.

The height and size the determine plants grow to depends on the specific variety, but they will not grow out of control like vines.

5. Snip Back Other Leaves

For indeterminate, vine-growing tomatoes, it’s also a good idea to use your sharp, clean pruners to snip any leaves below the first branches with flowers or fruits.

Cutting these away will help to keep a distance between the first leaves and the soil which may help.

Soil naturally contains all manner of bacteria and viruses, not all bad. Some will infect and affect some plants and not others, but maintaining that distance will help stop anything from creeping north.

Leaving a gap also means that when you water your tomatoes, you’re less likely to splash droplets onto your plant, which is another way nasties can spread.

6. Avoid Pruning Too Much

As mentioned above, there are no hard and fast rules about how much you should prune your tomato plants. 

Some gardeners swear by removing all the leaves from their plants. The idea is that all energy is then directed into the fruit and nothing else. 

However, most gardeners recommend some pruning; but do suggest avoiding taking off too much. 

Pruning is good to prevent overcrowding to give your tomatoes space because it will lessen the chance of disease. However, the leaves are a plant’s energy center and where photosynthesis occurs. 

7. Top The Plant

Once you reach the end of the summer, and you know the first frosts may be on their way, it’s time to think about ‘topping’ your plant.

When topping, you quite literally take the top off the primary stems. Taking the tops off each main stem stunts their growth and redirects energy into ripening existing fruit rather than getting bigger.