Preparing Raised Beds: Killing Weeds and Grass Organically

A gardener building raised beds wants to eliminate existing weeds and grass before filling with a compost/sand/vermiculite/peat mix. Tilling in winter may not fully eradicate perennial weeds.

Organic Weed Killer Recipe

• 1 liter (35 fl oz) boiling water
• 5 tsp vinegar
• 6 tsp table salt
• 1 Tbsp lemon juice
• 2 tsp powdered dishwasher detergent

Mix carefully (hot water can burn). Apply to weeds on a sunny day for fastest results. This contact killer disrupts cell membranes but doesn't persist in soil, so it's safe for earthworms and pets once dry.

Alternative: Remove Topsoil

Dig out the top 4 inches of soil (including weed roots), set timbers, then fill with a clean growing medium. This avoids herbicides entirely and gives a fresh start.

— Mack Jean, Master Gardener, Tennessee