Rust can form on your griddle top if the steel is able to interact with oxygen and water. This is also known as oxidation.
- Use your griddle frequently! Every time you cook, you are adding to the seasoning, which makes rust less likely.
- If possible, store your griddle out of the elements, like under awning or in a shed. If you don't have a good place to store your griddle, you can also remove the griddle top and store it inside if you won't be cooking for over a month.
- If you are using a soft cover on a unit that doesn't have a hood, make sure to tent your cover in the center. This will allow water to drain over the cover. If the cover gets beaten down, water can pool on top of the cover and start soaking through onto your griddle surface.
- Consider pairing your soft cover with a hard cover. This will give your griddle top the best protection.