Why are there holes in the leaves of my plants?

If you discover holes in your leaves, this is usually a sign of pests rather than a disease, which will often lead to sports or the leaves dropping altogether.

Holes are initially caused by little insects munching away at the leaves- i.e., caterpillars. Try looking on the underside of the leaves and see if you can spot any insects or signs they've been there. Caterpillars, for example, will leave little green pellets behind; slugs will leave a shiny trail.

Ensure you select the correct treatment. Pick off caterpillars by hand and drop them into soapy water. Slugs and snails can be treated with a commercial product, or you can just pick them off at night by hand if you prefer!

With time, pests will disappear off on their own, and you don't need to do much to get rid of them- unfortunately, it's just one of those things with plants. Over time, your plant will recover and a few munched holes will not stop your plants from growing well. However, should you feel your plant needs it, using methods like the above is always a good way to solve the problem.