Claire Mummery: Why and how to prune your plants throughout the summer

Pruning the right leaves is important, but reasonably simple. Photo / Getty Images

While pruning is a gardening task most typically associated with the winter months, pruning of summer crops has been an essential part of my gardening journey over the past three years. By lovingly paring back my fruit and veg during the sunny months, it has enabled me to minimise disease and control outbreaks of unwanted pests, so here are my tips to prune effectively in your summer garden.

Pest organisms are actually clever little things and it’s worth understanding their life cycles in order to notice and prevent them more effectively.

When insects lay eggs, it is usually on the underside of our plants’ leaves. This is done to keep their eggs and young safe and undetected, and to provide them with an immediate source of food when they hatch, ready to munch their way through our leaves and young vegetables. Clever!

When the eggs hatch under the leaves, the young usually start to suck the goodness out of our plants and our plants quickly weaken, in turn becoming more susceptible to disease.

This is where a regular leaf pruning ritual can really help. By removing leaves on a regular basis, it enables the grower to minimise the pest outbreaks and plant stress, as in doing so, you will usually find cocoons, eggs or even young pests under these leaves.

If the summer becomes very humid, a regular leaf prune also creates much-needed airflow around your plants. When the leaves are close together, they create a humid microclimate that actually encourages pests and disease to flourish. From the outside, it may appear that you have a thriving, leafy plant, but peek inside and you will start to see a different story…

Pruning the right leaves is important, but reasonably simple. A simple rule I follow is to avoid taking any leaves that sit directly above fruit, as these serve as cooling shade, and prevent sunburn. I also leave enough for photosynthesis to occur in the plant, usually 2-4 leaves is sufficient.

In my experience, the vegetables that benefit most from a summer prune are beans, cucumbers, melons, pumpkins, zucchini and tomatoes. In controlling pests, I have found this to be the most effective and efficient under the cucumber, melon and pumpkin leaves, as they have much bigger span capacity than the others, often revealing colonies I have been able to control!

With the above vegetables, I wait until the plant is established and has produced its first fruit before beginning to pluck leaves. After this, I will prune off any leaves that look unhealthy, have changed in colour or are curled up on a fortnightly basis. When pruning these leaves off, always remember to look underneath for cocoons and squash these before putting in the compost or bokashi, as this will prevent hatching. Cut leaves off close to the stems of the plant with a sharp knife or scissors. Do this on a dry day, preferably with a light wind as this will enable the wound to heal quickly and prevent any disease from entering the plant.

If your leaves are diseased with powdery mildew or mosaic virus, I would recommend spraying these with a good oil before removing, which will help stop the diseases spreading through the air as you move them.

For tomato plants, I recommend a slightly different approach. I will always snap the bottom 30cm of leaves off to create airflow and then only leave the leaves covering the tomatoes. I always snap the leaves off on a windy dry day, remembering to give the plant enough time to dry out before the evening arrives. If these leaves are disease-free, place them in a bucket of water and leave for 24 hours, then use the water to feed the tomato plants, which they absolutely love and it causes them to go for gold! My grandfather taught me this incredible trick, so it has been normal practice for me over the past 30-plus years.

Last, but by no means least, is to remember to water your plants at the base only, never overhead, so the roots can absorb straight away, you avoid burning your plants and this will also help with disease prevention.

Happy gardening!

For more gardening advice, visit growinspired.co.nz and discover Claire Mummery’s online gardening course at www.growinspiredacademy.com