Using Lye Under Deck for Weed Control: Dangerous, Use Alternatives

Lye Under Deck: Burn Hazard, Not Recommended

Lye (sodium hydroxide) causes severe chemical burns on skin contact. Unsafe for kids/pets.

Glyphosate (Roundup): Kills green plants. Apply to weeds only.
Horticultural vinegar (20% acetic acid): Contact kill. Add dish soap for waxy leaves.
Physical barrier: Heavy landscape fabric + gravel under deck.

Barrier method is longest-lasting and non-chemical.

Trees: Lake Algae Ecology: Nutrient Cycling and Management Realities; Organic Aloe Vera Black Spots and Weed Control; Using 20% Vinegar as an Organic Herbicide: Efficacy and Safety; Vinegar Weed Killer: Non‑Selective, Protect Desirable Plants; Vinegar as Weed Killer: Science, Strengths, and Limits; Vinegar, Stickers, and Crabgrass in Oklahoma: Organic Approach; Vinegar Beats Weed Barriers for Schoolyard Weed Control; Vinegar as Weed Killer: What Works and What Doesn't; Vinegar as Weed Killer: Science, Limitations, and Legal Products; Acetic Acid (Vinegar) Herbicides: Not as Safe as Advertised

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