I urge people who use fertilizer to make their own compost. DIY composting bins can be made pretty cheap, it also cuts down on how much trash you have to put out, you know exactly what is in your fertilizer, and you don’t have to pay for fertilizer. I’m starting my first garden this year, and I plan on making a very large compost bin
I know it’s how most things are grown, but I’ve always had a problem with putting poo on things. Especially things I intend to eat.
The natural products grown using non-vegan fertilizer are still vegan, it’s just the process of growing them that’s not. However as @Dagmar has said, how will you know if what you buy has been fertilized with vegan stuff or not?