It won’t be long before butterflies and moths start laying their eggs…and not long after that the caterpillars will have a good chomp on any leaves that they find tasty. You can always be one step ahead though, keeping your precious crops protected.
The first thing is to be aware of which plants are most at risk. Brassicas (cabbages, broccoli, cauliflower and kale) appeal greatly to butterflies and moths. You’ll need to be extra vigilant with these plants and put a few defences in place when you plant them. Other plants, like spinach and chard, aren’t at such a great risk but will need to be watched.
The key to keeping your brassicas safe is preventing eggs from being laid in the first place. The best way to do this is to create a barrier of fine, insect-proof netting or horticultural fleece. You can do this in any way you like and there are plenty of ready made net tunnels that you can place over an entire row of plants, and tunnel hoops so that you can make your own. For a make-your-own version, we recommend sticking a few bamboo canes in the ground between rows, placing a jam jar on top and then laying netting or horticultural fleece over the top. Make sure the fleece/netting reaches the ground and secure in the corners with stones.
Another great way to keep brassicas safe is by using companion planting. The idea is to plant some nasturtiums nearby. The nasturtiums are even more attractive to butterflies and moths than the brassicas, so eggs will be laid here instead. When they hatch, your nasturtiums will be munched before your very eyes and your brassicas will remain safe and sound!
Finally, it’s a really good idea to check your plants on a daily basis during May and June in particular. Look on the undersides of leaves and in the corners between leaf and stem keeping an eye out for clusters of eggs (very small, usually white, black or yellow) and newly hatched caterpillars. Wipe off any that you find using kitchen paper. Catching them early will prevent too much damage being done.