Raised bed gardening what to put on bottom

Hi

When building a raised bed garden, do you put anything on the bottom - eg between the ground soil and the raised bed soul

many thanks

 

If the depth of the raised bed is about six inches or lower, put down a layer of cardboard, paper, leaves etc on top of the ground soil to exclude light so that the weeds below will be weakened or killed off. Then put your compost or raised bed soil on top of that.

If the bed is really tall, say, more than 12 inches, include other things like tree branches, fruit/veg scraps, grass clippings etc. Do this in layers and add in a few thin layers of the ground soil to incorporate soil microbes to help break down the mix. Then top off the remaining six inches with your compost or raised bed soils.

Most common garden crops which do not require really deep tap roots can be grown in as little as 8cm of soil depth so six inches is more than enough.

 

Many thanks for this, really useful.

So just to clarify, the raised bed I'm building is exactly 12 inches high. So for the first 6 inches I would put alternate layers of grass clippings etc as you suggest and ground soil and then the last 6 inches would be bought compost.

Looking forward, would I add anything else as the plants grow etc

 

Search online for hugelkultur raised bed. This will show you the principle. As misterQ said I would put a good layer of cardboard as the first layer. You will probably need to top up after the first year as the materials decompose as the level will drop. Also give it a good soak before adding top layer of compost.

Rusty