Although botanically, the tomato is classified as a fruit, it is usually considered a “culinary vegetable”. With summer in front of us, we need to start thinking about our vegetable gardens.
Therefore, today’s topic is tomatoes. In particular, how to prune your tomatoes. With pomodori (that’s Italian for tomatoes), the goal is to maximize the efficiency of photosynthesis and minimize the risk of disease.
Pruning is the best way to do that. A pruned and staked plant will produce larger fruit two to three weeks earlier than a prostrate one.
Why prune tomatoes?
To achieve that efficiency of photosynthesis you need to make sure that each leaf has enough space and is supported up off the ground.
If your tomato plant lies on the ground, or when its growth is extremely dense, the leaves may be forced into a permanent shade. This will reduce the amount of sugar that they produce. If a leaf uses more sugar than it makes, eventually it will yellow and drop off.
On the other hand, when a tomato is properly pruned and supported, the sun will shine on all of its leaves. The sugar produced in them will be directed towards the fruits since the only competition will be the single growing tip. Thus, it will produce large, healthy fruits and the production will continue until the end of the season.
Pruning is used mostly to keep plants tidy, to speed ripening and to manipulate fruit size. However, you need to keep in mind that you should prune only indeterminate varieties.
They produce new leaves and flowers during the whole growing season. Pruning is best for plants, which are trained on strong vertical support, for example, a trellis. The right way to prune is to prune enough, but not too much.
Pruning determinate varieties is not recommended, since it may reduce the harvest. They require little to no pruning at all.
Tomato pruning tools
The one and only tool that you need for pruning tomatoes is a pruner (a.k.a. garden clippers). Pruners are easy to manoeuvre, as they are a hand-held tool and are easy to work with on the tomato plant.
As well as that, their size matches exactly the tomato branches, as they don’t cut anything bigger than 1 inch.
There are three different types of clippers, differentiating by size, shape and sharpness. Their common names are bypass pruners, anvil pruners and ratchet pruners.
For pruning tomatoes, the best choice is bypass burners because they are good for maneuvering in tight spaces in between branches and best for live stems.
What are the benefits of pruning tomatoes?
There are few important benefits you need to know about!
Earlier ripening
Extra stems divert energy from the main plant’s fruit production. Removing the extra growth focuses more of the plant’s energy on ripening existing fruit, which can lead to an earlier harvest. When the plant has fewer fruits to take care of, they ripen faster.
Bigger fruits
Pruned plants take up less space and can be placed closer together. Thus, pruning can reduce the yield per plant, but it allows us to grow more plants in a given area, thereby increasing the overall yield.
Pruning ensures that you will have fewer fruits but they will be bigger. When tomatoes are pruned, more leaves are exposed to sunlight and they can produce energy for the plant. Directing this energy to fewer branches and blossoms after the pruning will produce larger fruits.
Better airflow and fewer diseases
To combat early blight and keep your plants healthy, you need to prune all the leaves that hang within a foot from the ground.
Early blight is a fungus that colonizes on leaves and produces brown spots. It can eventually kill leaves and significantly reduce fruit production. Lower leaves are typically infected first due to their proximity to the ground.
During rainstorms, early blight spores in the soil can splash up and come into contact with leaves. Pruning the bottom leaves not only eliminates infected leaves and those likely to be infected, it also increases light penetration and air flow, creating a less hospitable environment for the fungus.
Bottom pruning should be done after plants are at least 4 or 5 feet tall or when you see infected leaves.
Determinate vs indeterminate tomato plant
What are determinate tomato plants?
Determinate tomatoes are bush tomatoes that usually don’t grow taller than 4 feet. They have a predetermined number of stems, leaves, and flowers hardwired into their genetic structure. Their fruit ripens at roughly the same time and then the plant dies.
How to prune determinate tomatoes
Pruning determinate plants will significantly reduce their yield. Because of this pruning is generally not practised. You can only prune suckers below the first flower cluster. This won’t affect their fruit size or plant vigour. Pruning anything above the first flower cluster means throwing away potential fruit.
What are indeterminate tomato plants?
Indeterminate tomatoes are vining tomatoes that keep growing and putting out new suckers, buds throughout the whole season. Their growth is limited only by the length of the season.
Indeterminate tomatoes usually grow on trellises and need to be spaced only a foot apart. Each sucker of an indeterminate tomato essentially produces a whole new plant, so pruning them makes this close spacing possible. It also allows for adequate light penetration and airflow around plants. If you don’t prune, the tomatoes would have to be 2 to 3 feet apart.
How to pune indeterminate tomatoes
Prune suckers that are developing below new blossoms. It’s best to prune suckers when they’re relatively small.
Removing a more mature sucker would leave a larger wound, which could be more susceptible to infection.
When identifying suckers, you can think of the sucker as an extra arm growing out of an armpit. The intersection between the main stem and the branch from the armpit and the sucker is the extra arm growing out of it.
You may have some tomatoes that are already taller than the trellises. If you don’t top off the plants, they could very well be 12 feet tall by the end of the season. Of course, they wouldn’t just keep growing straight up.
Instead, they’d slouch over the top of the trellis and hand down over the rest of the plant, which would create a tangled mess and increase the plant’s vulnerability to diseases. Therefore, you need to prune the plants just above the top of the trellis.
Topping them off will also help the plants focus their energy on producing fruit, which is your ultimate goal after all.
Pruning techniques
Throughout the season you’ll need to prune your tomatoes. There are three different pruning techniques that you’re going to need. Here’s what to do and when:
At planting
When you’re planting the tomato you should remove all the lower leaves so you can bury it deep into the soil.
Remove any flowers present at planting time. (even if they were present when you bought the plant). By doing this, you will ensure that all the energy goes into leaf growth instead of fruiting at this early stage.
Early/mid season
Remove all leafy suckers beneath the first fruit cluster. Otherwise, they’ll slow down the development of the fruit. This is best to be done early season when the suckers are still small. When the plants are between 12 and 18 inches tall it’s time to remove flowers, so more energy is directed to the roots.
Late season
At the end of the season, you can remove the growing tip of each main stem to speed ripening. This pruning technique is called “topping” and needs to be done about two weeks before the end of the season.
It will cause the plant to stop flowering. Thus, it will direct all sugars to the remaining fruits and they will ripen faster. Topping is totally optional and you can skip it if you want.
Tomato pruning methods
There are a few simple pruning techniques that you can master.
Simple pruning
Carefully grasp the base of the sucker between the thumb and forefinger. Pinch it or gently bend the sucker until it snaps. It’s best to be done when the tomato sucker is young. Pinched wounds heal quickly and are less vulnerable to diseases. This is called “simple pruning”.
Or: If the sucker has already grown thicker and stronger you can simply use garden pruners. Just keep in mind to disinfect them before you do the pruning to prevent an infection.
Missouri pruning
The Missouri pruning is used mainly because it reduces the shock to the plant. As we already mentioned, the “Missouri” pruning is pinching only the tip of the sucker. By leaving the last two leaves on you allow the plant to produce more energy for ripening tomatoes. This will also help shade the fruit and protect it from sunscald.
Downside: The remaining sucker will grow new suckers on its own.
Root pruning
Pruning the roots of a tomato plant is usually used to speed up the maturing of the plant. It stresses the plant, as it interrupts its natural growth cycle and thus, it forces it to mature faster. The best time for root pruning is the time when the first clusters of tomatoes ripen.
How to do it: Use a pitchfork or a spade and insert it a few inches from the base of the plant, penetrating the soil 8-10 inches. After that, simply make your cut halfway around the plant.
Top pruning
Another type of pruning that we already mentioned is top pruning or topping. About 1 month before the end of the season remove the growing tip of each main stem just above the last blossom.
This directs all sugars and nutrients towards the fruits and gives you a better chance of final harvest of red tomatoes rather than green.
Must be done: Four weeks before the end of the season.
How to prune cherry tomatoes
The cherry tomato is an indeterminate tomato plant. This means that it’s going to grow until disease or cold weather take it. The best thing to do for cherry tomato plants is to grow them in a cage, rather than on a trellis. The cage takes up more space but it allows you to retain up to 4 or 5 main shoots.
This results in a greater yield. Another thing, from which the cherry tomato plant benefits greatly is the pruning.
Regular pruning improves the quality of fruit that the plant produces. Therefore, it’s best to monitor your plant and follow these steps:
Step 1: Start by pruning all the leaves from the lower portion of the young tomato plant’s stem. This must be done at the time of transplant, as it allows you to bury the plant deeper.
Step 2: If the plant is supported by a stake or a trellis, pinch back shoots selectively so that it has two or three main stems. If it’s supported by a cage you can leave up to four or five.
If the cherry tomato plant has already developed larger stems than you want to remove use pruning shears or knife.
Step 3: Pinch back new suckers that appear in leaf axils, where the leaf stem meets the main stem.
Step 4: Monitor the cherry tomato plant for symptoms of disease and pest activity. If you notice leaves that have squiggly lines on them, spots or fuzzy growth on leaves, or pests visibly feeding on the plant pinch the affected parts of the plant.
Step 5: Dispose of the diseased or infested parts, which you removed from the plant well away from the cherry tomato and other plants.
- Rule 1: Get plants off the ground.
- Rule 2: Give plants room.
- Rule 3: Never prune or tie plants when the leaves are wet.
