Ontario's Cosmetic Pesticides Act bans 2,4-D and most weed killers. We compare Fiesta, corn gluten meal, EcoSense and manual tools — and explain why weed control alone never fully works.
No. Killex contains 2,4-D, mecoprop, and dicamba — all three are on Ontario's Schedule 1 prohibited list for cosmetic outdoor use under the Cosmetic Pesticides Act. Applying it to a residential lawn in Ontario is a provincial offence regardless of where you purchased it.
Fiesta's efficacy drops significantly below 12 to 15°C. In early May when daytime highs are still in the 10 to 14°C range, results may be slower and less complete than applications later in the season. For spring treatment, apply Fiesta when daytime temperatures are consistently above 15°C — typically mid-May in the GTA. Corn gluten meal in late April is the better early-season tool.
Fiesta is generally considered low-risk to pets — the active ingredient is an iron salt. The standard recommendation is to keep pets off the treated area until the spray has dried completely, typically 2 to 4 hours after application.
After. Core aeration opens channels in GTA's compacted clay soil that improve both water infiltration and the effectiveness of contact weed control products. Apply Fiesta 48 to 72 hours after aeration for maximum penetration. Do not apply corn gluten meal within 6 to 8 weeks of overseeding — it will inhibit grass seed germination.