How to Aerate Your Lawn
Step-by-step guide to core aerating your lawn. When to aerate, how to prepare, machine operation, and what to do after aeration for best results.
Run your sprinklers the day before aeration so the soil is moist but not muddy. Dry, hard soil resists the aerator tines and produces shallow plugs. Soggy soil clogs the machine. Aim for the moisture level you'd want for digging: a screwdriver should push in easily to 4 inches.
Walk your lawn and place flags at every sprinkler head, valve box, and shallow utility line. The aerator tines penetrate 2 to 3 inches and will crack sprinkler heads on contact. Also mark any invisible dog fence wires. One broken sprinkler head costs more than the entire aeration.
Run the aerator across the entire lawn in one direction, then make a second pass perpendicular to the first. This creates a grid pattern of holes spaced 2 to 3 inches apart. Two passes produce roughly 20 to 40 holes per square foot, which is the density needed to meaningfully reduce compaction.
Broadcast grass seed over the freshly aerated lawn while the holes are open. The seed falls into the holes and has direct soil contact for germination. Apply at your species' recommended rate: 6 to 8 lbs per 1,000 sq ft for tall fescue, 2 to 3 lbs for bluegrass. Then apply starter fertilizer (high phosphorus).
Keep the top inch of soil consistently moist for 14 days after seeding. This means light watering 2 to 3 times per day for 5 to 10 minutes each. After germination (7 to 14 days depending on species), transition to deeper, less frequent watering to encourage root depth.
Do not rake up the soil plugs. They break down in 1 to 2 weeks and return nutrients to the soil. Mowing over them speeds decomposition. They look messy but they're doing good work. Resume normal mowing when the new grass reaches 3.5 inches.
