Core aeration (warm-season)

Timing for warm-season grass

Aerate when the lawn is growing at full speed, so it closes the holes within a couple of weeks. For Bermuda, Zoysia and St. Augustine that is late spring into early summer, mid-May to the end of June in the northern hemisphere, after full green-up. Autumn aeration, right for cool-season lawns, is wrong here: the grass is slowing toward dormancy and the holes stay open all winter.

How

• Use a core (hollow-tine) aerator, pulling plugs 7–10 cm (3–4 in) long.
• Water the day before so the soil is moist but not wet.
• Make two passes in different directions on compacted areas.
• Leave the cores to dry and break them up by mowing or dragging a mat over them.

Afterwards

Feed and water normally; the lawn recovers fast in summer heat. Do not aerate within a few weeks of applying a pre-emergent, as it breaks the barrier. Once a year is enough for most lawns, twice for heavily used ones.