Extra mow in a growth surge

Why it happens

A spell of warm, humid weather after rain, especially soon after a feed, can double a cool-season lawn’s growth rate in late spring or early autumn. Stick to a fixed weekly mow and the grass gets ahead of you; then the next cut either takes off far more than a third or leaves the lawn long enough to flop and start setting seed heads.

What to do

• Mow as soon as the grass is dry, at the normal height, taking off no more than a third.
• Expect to mow again three to four days later while the surge lasts.
• If it is already too long, raise the mower one or two notches for this cut and lower it again on the next.
• Collect the clippings; heavy, wet clippings left on the lawn smother it.

Avoid making it worse

Hold off on nitrogen feeds until growth settles. Keep the blade sharp, as soft, fast-growing grass tears easily. When the weather settles, go back to the normal schedule; see spring mowing.