[allotment-shed]

I've been planning to build a raised bed on the plot, one patch of ground is particularly hard clay so it seems the obvious choice to build the bed. Some scaffold boards have at last be purchased and it should be 10ft long by 4ft wide when finished, would anyone say about two planks high, that's about 18in would be OK?

We have a good source of well rotted farmyard manure and compost is coming on well in the bins to fill it with.
If anyone can offer other advice I'd be most appreciated, thanks.

[Goosegirl]

I'd use two planks so the added compost etc won't fall out over the bed. It's amazing how quickly the soil level falls as you will see over winter so you will be able to top-up with more later on. Before you add the compost stuff, dig a trench in the bottom of the bed and fork in a mix of grit/sharp sand with compost as you go to help with drainage, then back-fill with a mix of your dug-out soil and compost.

[allotment-shed]

Thanks for your idea of digging a trench with grit and sharp sand for drainage, had thought of digging over the clay to help, but that sounds excellent to me, thanks.

[Robster]

When I made my raised beds I wish I had taller sides so that I could incorporate more manure compost etc as the years go by.  I think I'd now go for 8 inches clear at soil level