Max Slope?

We are going to introduce a bed across our front garden. Its currently gravel. Dims are roughly 8m x 2m. In the 2m direction there is a fall of about 300mm, slightly less probably. Is that too much? If so I can take some of the slope out using sleepers, what should I reduce it too?
Thanks for any advice.

 

Hello fred88, if you've got the choice and a clean slate, go for level! IME it's so much easier to water effectively if it's not trickling off down a slope. It will also give you a good depth of soil which I'm sure the plants will appreciate.

 

Level would be nice but we don't want to have a terraced garden to the that extent. So is 12 degrees ok, maintainable etc?

 

I'd be inclined, sorry about the pun, to keep the slope dig it over incorporating some of the gravel and plant it up with drought tolerant plants, mostly low growing and spreading to hold the soil in place.