Know Your Chemicals - Pre-Emergents
Pre-emergent are herbicides designed to kill weed seeds BEFORE they sprout. They are usually granular and are applied to lawns and flower beds in the spring, but they persist for three months – that means prolonged time for human exposure.
Below we have gathered important information about some typical active ingredients and their effects:
Prodiamine – carcinogen, neurotoxicity
Pendimethalin – extremely toxic to fish and aquatic organisms
Isoxaben – possible carcinogen, kidney/liver damage, toxic to birds
Oxyfluorfen – possible carcinogen, reproductive, birth and development effects, kidney/liver damage, skin irritant, toxic to fish and aquatic organisms
Oryzalin – kidney/liver damage, skin irritant, birth and developmental effects, toxic to fish and aquatic organisms
Trifluralin – extremely toxic to fish and aquatic organisms
Also, since the active ingredient is usually only 1% ... what are the 99% "other ingredients" ? They are often a blend of equally toxic ingredients that amplify the deadly effectiveness, which means they are even more toxic for you too.
Safe alternative? Although corn-gluten is often recommended as an organic pre-emergent for lawns, it is expensive, and timing is too critical to be effective, so we don’t recommend it. The PRFCT nature-based approach to weed control is to outcompete weeds in lawns. Overseed lawns in the fall or early spring before weeds germinate. In shrub and flower beds plant many small plants close together, leaving little to no space or sun for weeds. More plants is always a better option for filling space than bark mulches from far away.