Why are my grass tips white after mowing?

Because the grass was torn rather than cut, and the damaged tissue at each tip has dried. It is the clearest visible diagnostic on a lawn, and it points at four things.

1. A dull blade

The usual answer. A blunt edge pushes the stem over and rips it, leaving a ragged end with a much larger damaged surface than a clean cut. Two days later it whitens.

This is why blade sharpness is a lawn-appearance question and not only a machine question, and it is the first thing to check.

2. Blade speed lost in the cut

Even a sharp blade tears if it is not moving fast enough when it arrives. A machine bogging in long or wet grass, or one whose deck is packed underneath, loses tip speed on every pass. The symptom is identical to a dull blade and the fix is different: raise the height, clean the deck, cut less at once.

3. Cutting too much at once

Taking more than about a third of the height leaves a large cut area on every stem, and a large cut area dries and discolours whether or not the cut was clean. A lawn scalped after a holiday goes pale for a week and that is not a blade problem.

4. Not the mower at all

Certain grass diseases produce bleached tips, and drought produces a pale, dull cast over the whole sward rather than at the tips alone. The distinguishing question is whether the discolouration follows the mowing — appearing a day or two after each cut and growing out between them.

What to do

Sharpen or replace the blade. Raise the cutting height a step. Clean the underside of the deck. Then mow and look again two days later; if the lawn stays green, it was the cut.

How this site handles it

The blade shelf here treats a blade as a consumable with a working life, and the robot blade shelf does the same for the small pivoting razors — those have a much shorter life than owners expect, and the manufacturers say so in their own manuals.