Field guide

Why the yard smells after rain

It feels backwards: the sky just washed the yard, and the yard responds by smelling worse. The explanation lives under the blades.

Artificial turf is built to drain. Urine doesn't sit on the surface waiting for a hose — it slides past the blades, through the perforated backing, and beds down in the layers underneath. There it dries, concentrates, and crystallizes into ammonia compounds a surface rinse never touches.

Rain re-wets those crystals. Rehydrated ammonia is enthusiastic ammonia — it evaporates upward through the turf with the next stretch of sun, which is why the smell blooms on the first warm day after a storm. The water wasn't cleaning; it was reviving.

The fix is to send something down the same drain the urine used. Sprayed through the BioSiphon, BioS+ rides the water past the backing and digests the crystals where they live. And because heavy rain can also carry working product away, the label's advice is practical: after a real downpour, move the next treatment up rather than out.