Why, If, When, and How to “Pinch” Your Seedlings

“Pinching” a plant refers to the process of snipping off (or literally pinching with your fingertips) the top of a plant when it’s young, in order to promote a bushier plant that eventually yields more blooms. While it’s recommended for the majority of annual flowers, there are specific ways to pinch - and not to pinch - to ensure a healthy harvest all season long.

Why to Pinch a Plant

Pinching a plant limits growth from the central, larger stem, and instead redirects the plant’s own energy to its lateral growth - in other words, smaller, side stems. This abundance of new side stems creates a bushier plant that will ultimately produce far more flowers. Every variety responds a bit differently, but it often leads to the plant producing at least double the number of flowers compared to its “non-pinched” counterparts.

If You Should Pinch Them

The majority of tender annual flowers respond well to pinching - but of course, there are exceptions! Single-stem varieties, like most sunflowers, for example, should never be pinched. Common “cut-and-come-again” flowers, though, like cosmos, zinnias, dahlias, celosia, sweet peas, snapdragons, and amaranthus all will produce larger harvests if they’re pinched.

That said, I occasionally leave sections of some varieties un-pinched. This is because the process of pinching delays the plant’s blooms by a couple of weeks, on average. (The central stem would have produced the first flowers, and the pinching process prevents this from happening.) When we are custom-growing for a wedding or special event early in the growing season, those couple weeks can make all the difference in whether or not we’ll have our flowers in time. If the goal is to get flowers as quickly as possible, it’s best to leave a third of them un-pinched.

When to Pinch Your Seedlings

As a general rule, it’s best to pinch plants when they are about 8-12” tall with at least three sets of leaves. For many varieties, this is a month or less from when they were started from seed.

How to Pinch Seedlings

Some gardeners like to use their fingers to pinch plants, but I find it easier to use a sharp pair of snips, or flower scissors. On a plant that is about 10” tall, you’ll snip just above a set of leaves, about 2-3” down on the plant. It’s never recommended to snip off more than a third of the plant’s total height.