Pinching zinnias is a horticultural technique that helps promote bushier growth and more abundant blooms. Ideally, you should pinch your zinnias when they reach a height of about 6 to 8 inches (15 to 20 cm). At this stage, select the central stem and pinch it just above a set of leaves. This encourages the plant to produce side shoots, leading to a fuller, more vibrant display of flowers.

It's best to perform this pinching in late spring or early summer when the risk of frost has passed, and the plants are actively growing. Remember, a healthy plant will reward your efforts with a spectacular show of colour throughout the summer months!