Raised Beds

kerri_gt

Hi, apologies if this has been asked before but we've had some raised beds built into our new patio - they're made of concrete blocks and rendered. Currently the bottoms are just hardcore and and 'blobs' of render that seem to have been lobbed about in the rendering process. Most loose bits of building materials have been removed but there's still enough 'stuff' at the bottom to assume the drainage would be pretty reasonable.

My question is whether I should / need to line the beds with anything else before planting - they will just have a couple of small ornamental trees and some grasses planted - nothing with special requirements. Or can I just fill the beds with soil and compost then plant up?

The builder has left a box with some hardcore and sand waste - wondering if I should put this at the bottom of the beds for additional drainage or whether it's not necessary.

The beds extend below the top level of the patio so there's no issue of anything escaping from the bottom into the paving.

Many thanks

Farway

Although not strictly necessary I would line the interior walls, not the base, with something like pond liner, or just old compost sacks or similar

Reason would be to stop damp creeping into the walls and subsequent external mould, not damaging but possibly unsightly in years to come

Mojisola

kerri_gt wrote: »

we've had some raised beds built into our new patio - they're made of concrete blocks and rendered.

they will just have a couple of small ornamental trees and some grasses planted

How high are the beds? Will you get a reasonable depth of soil in them for trees to thrive?

Grenage

If the beds extend below the slabs, I imagine a tree's roots will just move down and out.

kerri_gt

Mojisola wrote: »

How high are the beds? Will you get a reasonable depth of soil in them for trees to thrive?

prob about 50cm in depth - they are only small olive trees which we intend to keep small - the rest of the planting will be grasses

Mojisola

kerri_gt wrote: »

prob about 50cm in depth - they are only small olive trees which we intend to keep small - the rest of the planting will be grasses

That should be fine. Don't give them too rich a mix of new soil/compost - think of the kind of poor, stony soils they naturally grow on.