Epsom Salts, Aerator Sandals, and Thatch in St. Augustine Lawns

A Stuart, FL homeowner with St. Augustine grass sees yellowing. A neighbor suggested Epsom salts and bagging clippings to reduce thatch. They also bought aerator sandals.

Thatch Is the Likely Culprit

St. Augustine is prone to thatch—a ½–2 inch layer of partially decomposed runners, stems, and roots that blocks water, oxygen, and nutrients. Yellowing often results.

Better Than Sandals: Vertical Mowing

Aerator sandals punch holes but are minimally effective. Rent a vertical mower (verticutter/dethatcher) to thoroughly remove thatch. If the thatch layer exceeds ½ inch (check by cutting a soil core), dethatch.

Epsom Salts: Unlikely to Help

Epsom salts supply magnesium and sulfur, but yellowing is rarely due to their deficiency. They won't fix thatch, drought, insects, or disease.

Best Practices

• Water deeply when you water.
• Fertilize regularly with appropriate turf fertilizer.
• Mulch mow normally; only bag clippings temporarily if dethatching.
• Resume mulch mowing after dethatching.

Dethatch every few years as needed; it's the real solution for St. Augustine yellowing from thatch.