How to fill deep (11") raised beds

[WinnieParticipant]

I’m setting up two new wooden raised beds, 3ft square and 11″ deep. I’ve created a thick layer of cardboard on top of the lawn and have set the wooden beds on top of this. I have plenty of compost, perhaps not enough to fill them both completely, but certainly enough for a 6″ layer in each bed. I’m wondering what else I should use to fill the beds? Should I use all the compost I have? Should different materials be mixed together or layered?

[charlesModerator]

11in is a lot of compost and it will sink to 6 after a year. Put 5-6in soil in the bottom.

[WinnieParticipant]

Thanks Charles. I’ve recently moved house and it’s mainly lawn here, with a small flower bed next to the house, so I’d have to dig up soil from another part of the lawn or buy bags of soil, which could prove expensive. I wondered if instead I could incorporate other materials similar to this permaculture raised bed recipe, which I discovered yesterday:

Top layer: straw
Layer 2: compost
Layer 3: newspaper and cardboard
Layer 4: grass clippings
Layer 5: rough mulch
Bottom layer: branches

What do you think?

[charlesModerator]

You need to read this http://www.charlesdowding.co.uk/wp-admin/post.php?post=46&action=edit esp third para of Initial Preparation:
In damp climates such as the UK, I recommend not using mulches such as straw, which allow slugs to hide by day and eat your plants by night. Where slugs are potentially prevalent, compost is the mulch of choice because it does not harbour slugs. Composted beds look ‘bare’ where not growing vegetables, but there is a mulch of compost protecting the soil below.

Permaculturists often recommend straw mulches but British ones should know better. Straw and hay mulches are great in dry climates.

Why are you making such deep beds, 11in?

[WinnieParticipant]

Actually I wasn’t intending to use straw on top, but am interested in the alternatives to soil to sit beneath the 6″ layer of compost, i.e. branches, leaves and newspaper. That’s good advice, however, about straw in our damp climate. The permaculture page I was looking at was Australian, probably in an area with a much drier climate than ours.

The reason for such deep beds was that they were half-price in a sale, ready-made to slot together easily and the depth will make it easier for my arthritic husband to use. I bought them before reading your essential no-dig preparation guide. 😉 Since my last post I have managed to re-arrange the slats so that the beds are now 3″ lower. After measuring them I found that they were in fact 12″ rather than 11″ as was written on the label, so they’re now 9″ deep.

[LeifParticipant]

Could you not cut them in half? Buy or borrow some G clamps, get a piece of straight wood, clamp it onto the side of the bed, and then use a jig saw to cut the side in half using the clamped wood as a guid. Practice on some old waste wood such as bits from a pallet until you do a good job. Jig saws are cheap and very useful, but I’m sure you can hire or borrow one. You will get twice as many beds for the same price. Where you have cut the wood, you might need to paint on some preservative, depending on how it was originally treated.

[WinnieParticipant]

Thanks Leif. I’ve certainly considered cutting them in half and do have a jigsaw, as it happens. Thanks for the G-clamp tip. However, I’m also rather taken with the Hügelkultur approach and may endeavour to fill the bottom half with logs, branches and leaves gathered from my neighbours’ gardens and nearby woods.

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