Generally, you should try to keep your lawn at a height of 1 1/2" (40mm) in the spring and autumn and about 1/2" - 1" (13-25mm) during summer, however, if the summer is quite hot you should leave it a bit longer so it provides a bit of shade over the soil and help to protect the roots. In hot weather water it, (hose pipe ban permitting), lightly in the morning and evening. Do not give it a drenching as it can only absorb so much of it. Too much water will cause the roots to become waterlogged and can lead to rot setting in.
@Keital, what type of mower are you using? A hover mower? Electric with rear roller and grass box? Electric hover without grass box? Old style hand push rotary with/without grass box? With or without rear roller?
@Keital, what type of mower are you using? A hover mower? Electric with rear roller and grass box? Electric hover without grass box? Old style hand push rotary with/without grass box? With or without rear roller?