Preparing a Weedy Backyard for a Concrete Patio

Rain has sprouted weeds in the dirt where a stamped concrete patio is planned. The homeowner asks if weeds must be killed first.

Few Weeds? Pour Over Them

Concrete smothers and kills isolated weeds. No pre-treatment needed.

Heavy Weed Growth or Sod? Remove It

Organic matter (thick weeds, grass, roots) decomposes under concrete, creating voids → cracking. Strip to bare soil with a shovel or sod cutter.

Weed Killer

If desired, glyphosate (Roundup) or organic alternatives (vinegar, citric acid) work. Follow label. Wait 7–10 days for full kill before excavating.

Base Prep Is Key

Compacted subgrade + 4 in class II base + vapor barrier + reinforcement (rebar/mesh) = durable patio. The weed decision is minor compared to base quality.