New raised bed - ideal depth

[FuzzyFeltDeath]

Good evening everyone, I hope the Sun we've had the last few days has lifted everyone's spirits.

We've a rare weekend where the father in law is able to come and help build a proper raised bed with us.

It's looking likely to be two 1.2m x 2.4m beds, but what we can't decide is the height it should/needs to be. I've seen mention of a minimum of 8inches but 12inches being better.

I'm not 100% certain it's going to have much use for growing root veg as I don't eat much carbohydrates so root veg are off the plate, it's main use will be growing the likes of corn, squash, courgettes, strawberries and beans, giving some space back to the greenhouse for the warmer loving plants.

It's going to be built on an area that's currently grass, that's has well drained soil underneath, it would be filled with fresh tonne bags of compost or mix.

What wisdom do people who've had raised beds have towards the depth?

[Chestnut]

What kind of soil are you on? And are there any problems with drainage/flooding on your site?

[Penellype]

My raised beds are 5 inches high, on top of soil. I would think 8 inches would be fine, unless you need the beds to be higher for easy access.

The higher the beds are the more control you have over the composition of the soil to that depth, but because water will naturally drain downwards, higher beds will become dry more quickly and will therefore need more watering.

[FuzzyFeltDeath]

What kind of soil are you on? And are there any problems with drainage/flooding on your site?

The are is clay, clay and more clay, the main garden floods with any decent rain, and the water table seems very high, but..... the garden that we will use, is in fact what seems to be a man made garden way before our time. When I first rotovated it as the grass was terrible, we found it had a lot of old rock and brick under the top soil, so it was probably a site used when the house was extended to dump hardcore waste and then filled with soil. It sits about 6" off the drive but as it has a slightly higher centre.

We've never had any issue with drainage on it, and the chickens lived there for a year, so it's had some good fertilising done! At a guess it's probably not clay but soil from another site.

In fact here's a photo of it before we started tidying everything up, so it's had a new border by now.


The plan is to follow the hedge line to the right of the photo as it's South facing, the other section of that garden will be a playground area for the two little ones.