I have another question, besides plain salt which has to be used too?

http://homeguides.sfgate.com/homemade-bug-killer-hostas-77559.html

Hi Katrina,

You don't mention what is eating your hostas, but I found an article that mentions several different animals. I hope this helps you. Wishing you the best.

https://www.hostasdirect.com/learn/control-hosta-pests/

Rabbitts and squirrels are the hosta eaters, and also slugs. For the slugs try crush up egg shells or oyster shells around your plants, for the rabbit and squirrel, use ground up Irish spring soap and sprinkle around. In other words all three should be used.

Put some small containers of beerin the ground near your plants. Make a hole and set the container (I cut pop can about 2 inches up from bottom, be careful the cans are sharp once cut,) inside the hole push the soil up to the edges of can, then poor beer into the can stopping about 1/2 inch from the top.. next morning you will have a can full of drunk dead sluggs. Good luck