Raise bed in cement backyard

Hello ,
I am new in the community and will start to build a raise bed in my backyard that has a cement floor. do i need to build a wood floor to my raise bed ? To i need to fix the wood to the floor ?
there is some warnings or tips to place my raise bed under a cement floor ? do i need to build a
sewer system ?

Thanks for your precious help , try to search in the forum for a previous answer but has no luck.



Hey Danisam,

did you think about drainage?

yes @Klimbim, there is too much rain here.


Thanks @Klimbim will search again in the forum with Drainage key word.


This is what I did. The slab was pitched at 1/4" per foot. At the lower end the vertical supports stick out of the bottom of the box and are flush at the upper end. This left a small gap on 3 sides of the box between the horizontal boards and the concrete.


Thank a lot @John_D , will try and post here my final raise bed.