What are environmentally safe weedkillers?

Hot boiling water

Vinegar and salt

Boiling water. Epsom salt (sort of.) Vinegar or cleaning vinegar.

I heard also to add a little Dawn

Hand pulling them or Boiling water are only ones that are "Environmentally safe weedkillers" even vinegar, lemon juice, baking soda,salt, borax all cause damage to microbes that are essential to healthy soil/water which produces healthy plants. If you are asking about non-toxic to mammals, I just listed them.But these can harm fish/birds. The strongest mix vinegar lemon juice & salt spray on weeds in full hot sun.

https://ecocult.com/whats-the-difference-between-green-sustainable-eco-friendly-ethical-fair-trade-clean-organic-non-toxic-and-conscious/

Hi Hanneke - The struggle is real, I know! This is the most effective all-natural weed killer DIY that we use. It's even been featured on Hometalk! Hope this helps! Hugs, Holly

https://pinkfortitude.com/weed-killer/