The Wilderness Tamed Guide To Mowing.
I harp on about this more in the Lawns, borders & Wildflowers Article but here is a brief list of essentials that every gardener or landscape designer should know.
How to mow
Mowing itself is relatively straight forward. It is the mowing height that can cause problems. Almost everyone cuts at the lowest setting on the mower.
For the first mowing in spring, set the cutting height to the highest setting. Thereafter, gradually reduce the height of cut until the desired height is reached.
For ordinary ornamental lawns this will be 13-25mm (½-1in) in summer and up to 40mm (1.5in) in spring and autumn.
Avoid excessively close mowing, it weakens the grass, encourages shallow rooting which makes the lawn more susceptible to drought, weeds and moss. The lawn will need more frequent feeding and watering. Extremely low mowing scalps the lawn, leaving bare patches where there are bumps or tree roots protruding above the surface.
Lawns regularly cut too high can suffer from loose, weak growth that is less durable as a surface.
If you are unsure of what height to use, the general guideline is never remove more than one-third of the leaf shoots in any one mow.
This advice has come from the RHS website