Raised beds from excavated weed-infested topsoil - HELP

dh82

We've moved into victorian terrace with a small sunny garden that has a little 5x5m 'lawn' that is mostly dandelions. I'm going to pave over it and plan to use the excavated topsoil to make raised beds (we like raised beds but in any case the only access to the garden is through the house so don't we don't want to have to remove the soil entirely). 

What's the best way to deal with the weeds, so that we don't start these new beds with a weed infestation from the beginning? 

BobTheGardener

You can't do anything about weed seeds, but if you try and remove every piece of root you find when transferring the soil, you will remove any perennial weeds.  I would recommend mixing-in at least 25% well-rotted manure (the bagged stuff from garden centres is generally weed-seed-free) and then cover the surface with a 10cm later of the same and plant through it.  THe mulch layer on top wil prevent most weed seeds in the moved soil beneath from germinating and if you mulch every year in autumn with the same, the soil will stay in excellent condition.

nick615

You may like to consider a temporary solution of covering the whole (small) plot with either black plastic 'builders membrane' or roofing felt, either of which will stifle any weed growth underneath.  You could then punch holes in it, in which to plant whatever plants you fancy, and that will kill off all bar the most persistent weeds.  If you then take a look round about next February, and things don't look too bad, Bob's given you good advice for the future?

Chris-P-Bacon

Slice up the turf and stack it upside down..or roll it up. Lay your paving - saving any topsoil. Build the raised beds, place the turf grass side down on the base of the raised beds. (I'm assuming you don't have drainage issues and the raised beds are less than 300mm high and not placed directly on the paving stones) then fill with the remaining topsoil. Finally mulch with manure or soil improver. What you add to the soil depends on what you'd like to grow and you may still get the odd weed but nothing too bad.

dh82

Thanks everyone, that's really helpful