Rotation fails when it is run from the calendar, because grass grows by weather and season, not by the week number. A paddock grazed to the roots in a dry spell and given two weeks on paper has rested without recovering, while the same field in a wet spring may be ready noticeably sooner. Heights and rest periods together give a system a keeper can judge by eye at the gate: measure the sward, move the horses on a trigger everyone recognizes, and give the field a genuine recovery interval before it is grazed again.
Graze by Height: On at Six to Eight, Off at Three to Four
Bring horses in when the sward stands at roughly six to eight inches, with enough leaf to feed them and enough reserve left in the plant to power regrowth afterward. Take them off again once grazing brings the sward down to roughly three to four inches, before hooves and teeth start scalping the growing points and exposing bare soil. Grazing below that floor feels thrifty and costs dearly, because a plant cropped to its crown must rebuild from root reserves, weeds colonize the gaps, and the next grazing arrives later and thinner. Walk the field diagonally and judge the average rather than the lush corner by the trough or the bald patch by the gate, and accept that fields with heavy traffic areas may need those areas fenced off or rested separately. Keep a simple grass measure or a marked stick at the gate so different family members judge the same heights the same way.
Rest Through the Growing Season, Longer in Dormancy
Once horses move off, the field then rests, commonly three to six weeks while growth is active, with the shorter end suiting warm, wet weather and the longer end suiting slow, dry spells. That rest is when the real recovery happens: leaves regrow, roots rebuild the reserves spent during regrowth, and the break in grazing also interrupts parasite cycles, because larvae left behind in an empty field decline without hosts while the sward is resting. Through winter dormancy, plan on longer rest, because dormant grass is not regrowing at all, and turning horses onto a winter field is spending stored leaf rather than harvesting growth. Winter fields therefore need either generous area, a sacrifice area for the worst weather, or acceptance that the spring recovery will be slow. Fields recover during rest, they do not merely grow taller, and a field that looks long but has thin roots and patchy cover is not yet a recovered field.
Running the Rotation as a Household
Droppings management is the quiet partner of rest. Harrowing a rested field in dry, sunny weather spreads dung so it dries and breaks down instead of sitting in pats that horses refuse to graze around, which steadily shrinks the usable area of a small paddock. Where harrowing is not possible, picking up droppings from rested fields keeps the recovery honest and reduces the parasite burden waiting when horses return at six to eight inches, ready for the next grazing round in the rotation.
Divide grazing into at least three paddocks where land allows, so one is grazed, one is recovering, and one is ready, and harrow or top the rested field during its break to level droppings and cut back weeds before they seed. Note the date horses entered and left each field and the heights at both moments, because after a season those entries reveal which fields recover fast, which lag, and whether your rest interval is honest for your soil and climate. Adjust the pattern rather than defending it: persistent bare patches argue for longer rest or fewer horses per field, while fields consistently ready early may carry a slightly shorter break in a good growing year. Partners viewing the Family Sharing map on KinsLe can tell which paddock rests, which one hosts horses tonight, and when grazing resumes.