Everyone prunes tomatoes, but not everyone prunes cucumbers, but the science says you should. I have been working my way through a trove of scientific research papers to find out what works and what doesn't, and I have then broken that complicated reading down into a nice and easy-to-follow guide. So let's get into it and find out how to prune your cukes!
Why Prune Cucumbers?
One big reason is that studies have shown pruning cucumbers leads to bigger harvests, but the differences aren't huge if we are being fully honest, so why even bother?
Well, even if the differences aren't massive, more cukes is more cukes! But aside from that obvious point, there are many reasons you want to get your snips out and give those gangly vines a haircut.
One big reason is space efficiency. Many people, especially here in the UK, will be growing their cucumbers undercover, whether that be in a greenhouse or polytunnel. As soon as you grow undercover, space becomes your main limiting factor in how much you can grow.
By pruning our cucumbers and keeping them nice and tidy, they take up much less space than if left to sprawl. And they take up less space while actually giving us a slightly larger overall harvest, talk about a win-win. And factoring in the simple fact that you can now grow more plants because each plant takes up less room, suddenly your marginal gains from pruning have increased to doubling your overall crop by sneaking an extra plant in.
Another benefit of pruning cucumbers is that it helps to prevent diseases and pests. Removing dead or diseased leaves can reduce the risk of infections spreading throughout the plant. Additionally, pruning allows for better air circulation and sunlight penetration, which can help prevent fungal diseases, such as the all too common powdery mildew.
So the benefits are numerous, and I have hopefully convinced you to prune your cucumbers, but what is the best method to do so? Well, as I said earlier, I have been hard at work studying the scientific literature, and here are the pruning methods that worked best.
How To Prune Cucumbers
A couple of studies I have read have come to a similar conclusion regarding cucumber pruning. The basics are this: We train the plant up one main stem with zero side shoots and remove all lower growth up to 75cm on the plant.
The end result is one long stem, completely bare for the first 75cm, which then has lots of leaves and fruit above but no side shoots. So what exactly is a sideshoot on a cucumber plant?
Cucumbers have several nodes on the main stem off of which appear leaves, flowers & fruit, and a side shoot. This side shoot, if left to develop, will grow into its own stem with its own nodes. It is these side shoots we want to remove, this is very similar to how many people would prune a tomato plant.
I have edited the image above so you can easily see what a side shoot is. All of this growth, all the way back to the main stem, is a side shoot, and following our pruning method, it should be removed. Ideally, we would remove this much earlier than I have done in the photo, as all the energy that has gone into growing this side shoot has been wasted. But if we had pruned it earlier, that energy would have gone into growing the main stem and developing fruit instead.
What To Do When The Cucumber Reaches The Roof
Because we are removing the side shoots and pruning our cucumbers vigorously, the main stem is going to grow quickly, so what do we do once it reaches the top of its support and can no longer grow any higher?
The papers I read all had a straightforward approach to this problem: let it grow over the top of its support and continue growing back down towards the ground, problem solved!
Ongoing Pruning
When not removing side shoots, it is important to look for damaged or diseased leaves and remove them before problems begin to take root. I also like to prune any leaves that are in contact with the ground, as this provides an easy access route for plant diseases.
Common Mistakes and How to Avoid Them
Pruning cucumbers can be a simple and effective way to ensure a good harvest, but it's important to avoid common mistakes that can harm the plants. Here are some common mistakes and how to avoid them:
Mistake 1: Over-pruning
One common mistake is to prune too much, which can reduce harvest. It's important only to remove the parts of the plant that are necessary, such as the side shoots that grow from the main stem.
The main stem and leaves should be left as much as possible intact.
Mistake 2: Pruning too late
Another mistake is to start pruning the plants too late in the season. Pruning should start early in the season when the plants are growing quickly.
Mistake 3: Not providing support
Pruning can make the plants more compact and easier to manage, but it's important to provide support for the plants to prevent them from falling over.
Trellises, stakes, and cages can all be used to support the plants and keep them upright.
Frequently Asked Questions
How do I prune cucumber plants in pots?
Cucumber plants grown in pots can be pruned in the same way as those grown in the ground. It is important to provide support for the plant as it grows.
When pruning, remove any side shoots this will help the plant focus its energy on producing fruit.
What is the best time to prune cucumbers?
Cucumber plants should be pruned throughout the growing season. It is best to prune in the morning when the plant is less likely to lose water. Avoid pruning during the hottest part of the day.
What is the cucumber growth point and how do I identify it?
The cucumber growth point is the area where new growth emerges. It is usually located at the top of the plant, just above the last leaf.
To identify the growth point, look for a small, green shoot emerging from the stem.
Should I remove cucumber flowers?
It is not usually necessary to remove cucumber flowers unless you are growing a mix of varities, not all cucumbers like to be fertilised and if ones are fertilised that shouldnt be then it can actially lead to inedible fruit.
Learn more about this and male and female cucumber flowers here.
What is umbrella pruning and how do I do it?
Umbrella pruning is a technique used to encourage lateral growth and increase yield. To do this, allow the plant to grow to a height of around 2 feet, then remove the growing tip. This will encourage the plant to produce lateral shoots, which can be trained along a trellis or support structure.
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