Raised Bed on firm surface

pip2pip

I have a small garden that is entirely brick paved and am looking to place 3 raised beds for shallow rooting vegetables. The raised beds I have received come complete with liners for a hard surface.

These liners (19" depth") have no holes, surely they will need some putting in, and have gravel/crocks around them to prevent blockage.

I want to leave them in place from year to year, how best can I prolong the life of the compost I am using/how long before I have to replace it?

Any tips gratefully received

AllotmentDave

You're absolutely right, you will need drainage for the raised bed. One prolonged period of heavy rain without them and everything would be waterlogged.

I never replace the compost in my raised beds. I add a little each year to top them up.

Dovefromabove

I have an 'ordinary' wooden raised bed which I have lined with porous membrane to enable the bed to drain freely without the compost washing through and out of the bottom of the bed - mine is not on a hard surface, but I would have thought that the same system would work if it were. 

I filled the bed with a roughly half and half mixture of top soil and Farm Yard Manure, and each year I add a layer of well-rotted FYM to the bed about now and fork it in lightly.

I also add a sprinkling of Fish Blood and Bone before planting.  

Welshonion

My raised beds are on Tarmac - school playground.  The beds have no specific drainage.  They in fact dry out too much when the weather is dry.  If I were constructing them again (they are made from old floorboards)  I would line them round the sides with damp-proof course plastic to preserve the wood a bit longer.

I also do not replace the soil, just add more compost each year + compost from pots, etc.