Topping a tomato plant is a type of pruning. You may hear the term and think that you’re simply lopping of the top of the plant. And that is part of the process. But technically speaking, topping a tomato plant means removing all plant’s actively growing tips once the plant grows to the top of its cage or stake. Topping prevents those tips from growing.
Let’s say your tomato plants are too tall and leggy. Or your tomato plants are too tall with no fruit and you want to know how to make tomato plants bushy and productive once again. Those are also good opportunities to top your tomato plant, no matter what point you are in the growing season.
Gardening experts recommend topping a tomato plant about 30 days before your zone’s projected first frost. If you’ve grown tomato plants in the past, you understand why this makes sense. As the season drags on, tomato plants get leggy and fruit takes longer to ripen.
But you can top your tomato plant sooner than that, especially when it begins to spill over the top of its cage or grow beyond the height of its stake. Topping a tomato plant has several advantages.
Topping a tomato plant moves things along. As you prune the upward branches back to their last growth, the plant must direct its energy elsewhere. All those luscious nutrients concentrate themselves on the fruit. And those fruit are bigger and more flavorful.
Leftover nutrients also go to producing new growth and new blossoms. The plant puts out more lateral stems and leaves. That offers more shade to ripening fruit which they appreciate as they ward off sunscald from the hot, late summer sun. And new branches and new flowers means a longer season of fresh tomatoes for you when frost holds off.
Now that your tomato plant doesn’t need to support as much height, the center stem and new branches get more water, sunlight, and nutrients. They get stronger. They are less likely to break.
And if your tomato plants are supported in cages, then you have less tying and staking at the end of the season. If you’ve ever had to get on a ladder to add a cage extension during the hot days of midsummer, you understand what a relief this can be.
There’s no need to trim the tops of determinate tomato plants. Determinates are sometimes called “bush tomatoes” anyway. Their branch tips end in flower clusters.
Determinate tomatoes grow to a certain height and then stop. Their end game is “determined.” If you prune their tips, you’re telling them their season is done early. They’ll stop growing new branches and blossoms. All their energy will descend on the tomatoes currently on their vines and then they’ll shut down.
Of course, you want those tomatoes to ripen. But a few more days or weeks of production would be nice, too. Moral of the story: don’t top off determinate tomato plants.
Now that you’ve topped your tomato plant, you have tomato cuttings. You can compost them. But you can root these in water. If it’s early enough in the season, plant the cuttings in your garden or in containers. You’ll extend your harvest! That’s another argument for topping a tomato plant as soon as it gets too tall or leggy.
But let’s say you waited until late in the season to top your plants. If cold weather threatens, never fear. You don’t have to waste your rooted cuttings. Plant them indoors and you can have fresh tomatoes all winter long.
A word of caution in topping a tomato plant: don’t get scissors happy. If you over prune you plant, you can stress it. Your plant may never recover.
Instead, be prudent as you prune. Trim your plant enough to encourage more blossoms, a bushy habit, and faster ripening fruit. Your topped tomato plant will reward you with a longer harvest and a longer season and more luscious, fresh tomatoes.
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