Raised bed for raspberries - how high?

[Chestnut]

I would like to plant some raspberry canes in our garden next autumn, as I love eating fresh raspberries straight off the plant!

Unfortunately, the ground conditions are less than ideal; heavy clay soil, and the whole neighbourhood gets waterlogged in heavy rain (our garden puddled 4 inches above ground in the heavy rains last winter), not to mention an old poured concrete shed base a few inches below soil level.

I know raspberries don't like wet feet, so I'm thinking to make a raised bed. Not sure yet whether just to build on top of the concrete, or dig the concrete out

Question is, how deep should this raised bed be ? and how far above the surrounding soil level?

They need enough soil depth to grow happily, and to be far enough above the surrounding soil to avoid drowning - but ideally not so high I have to water them all summer!

Thank you in advance for any advice or experience you can pass on

[BUFFS]

I would thoroughly dig and raise the soil level no more than a foot or so, unless you can get the footballer Peter Crouch to pick them for you, mine, at ground level, reach up to six and a half foot tall, Joan J and Polka, so if you want a high raised bed you will need to go on e bay or amazon for some stilts, and I would dig a drainaway about 3ft plus deep to help avoid swimming roots..

[bramble]

Raspberries are shallow rooted so no need to raise them too much.

[johnjohn]

I can see that you might be reluctant to get the concrete out but if you did it would give you the opportunity to get a load of organic material in there which would benefit the drainage.

[Chestnut]

Thank you all. Glad I still have the best part of the year to get the raspberry beds prepared ;-)

I think I might be tempted to find someone with a pneumatic drill to break up the concrete though - pick axe vs 8x10' concrete could be very hard work!

[chrisdb]

We cut some rose beds into our concrete drive. Pick-axing it was impossible - cutting with power tools where we wanted the edge to be and then hitting it with the pneumatic drill was the only way. You'll just hurt yourself if you try muscle power on any self-respecting foundation.

[polc1410]

Yip - You don't want them high, you want to get a crack in the concrete!

[ESBkevin]

The raspberries are not that fussy but the best way to avoid clay soil is to double dig the first time and bury lots and lots of organic material, leaves, compost, manure, garden ot kitchen waste, cardboard, cheap soil improver, rotted wood and woodchip. Then each year mulch heavily to control weeds. The heavy composting in the ground will have the microbes worms and such digging and turning the soil into first class topsoil in one to two growing years, the extra mulch just keeps it there and you'll have weed supression, fertilisation and excellent moisture regulation. The only downside is that if you just dig a narrow trench to start it is still surrounded by waterlogged clay for a year or so until the wildlife under the surface spreads and improves the surrounding soil too.

[Chestnut]

Thanks All.
You've decided me on getting some professional help on the concrete (Electric drill and cake mixer are about my limit on power tools...)
I'm planning 2 adjacent rows, so will double dig/add organic matter to about 9' x 11' patch (once the concrete is out!). The last foot of the raising will be by far the easiest bit!!