Soft, Spongy Lawn in Houston: Causes from Leaks to Grubs

A 20-year-old lawn that suddenly feels soft underfoot — you sink in — with premature grass decline suggests subsurface changes. An oak planted 12 years ago may be a factor, but not via acidity.

Systematic Diagnosis

Wet softness: Check for irrigation or water supply leaks. Turn off water for 48 hours; if firmness returns, you have a leak.
Dry softness: Extreme drought can lower the water table, drawing air into soil pores — essentially natural aeration. Water deeply and monitor.
Spongy, not wet: Grubs eating roots create a loose, carpet-like sod. Tug the grass; if it lifts easily with few roots, treat for grubs.

Tree Influence

The oak's roots compete for water and nutrients, but won't cause sponginess. Focus on the three scenarios above.