Mulch-Lock Concentrate is a patented formula of bonding agents that helps lock mulch in place. Just spray it directly onto mulch or other groundcover, including pine straw, pebbles, gravel, sand and dirt, to lock in place for up to 12 months. Covers up to 1,500 square feet. Use Mulch-Lock Concentrate around trees, planting beds, slopes, pathways, borders, edging and driveways. It starts bonding immediately, with maximum bond after 24 to 48 hours. Although this formula locks mulch in place, it allows water and nutrients to flow through to plants and shrubs. Mulch-Lock Ready-To-Use sprays on milky white and dries completely clear. Spray Mulch-Lock when groundcover and air temperature is consistently 55 to 60 degrees or warmer and when the air is calm with no rain in the forecast for at least 24 hours. Results are best when applied in warm weather and direct sunlight. Do not spray if ground may freeze overnight.