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Raised bed advice - depth & lining options
suzquigley
Posts: 14
in Fruit & veg
Hi. I would love advice from experienced veg growers if you can help. I’m ordering 3 raised bed kits for my small garden, size 120cm x100cm each. I can’t decide whether to go for 27cm or 45cm depth. I was thinking the latter will be more versatile and easier to tend, with the downside being the expense of filling them. Any advice much appreciated. I have only grown potatoes in my garden so far but wish to grow a variety of veg.
Also, there is so much conflicting advice about lining them. Should I do this? The beds are attractive and should be good quality (safe pressure treated thick redwood) so I want to do all I can to preserve them as this is a pretty big purchase to me.
The beds will be set on my clay soil, in Scotland where it’s pretty wet. Thanks in advance!
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I would definitely lined them. I used empty compost bags which I cut into strips around the height of the boards and stapled into place, the black side facing out rather than the decorated exterior. I left around an inch at the top so the plastic didn't go right to the top, and which will be the height the soil will sit at (although you will probably want to fill to the top as the soil will settle over the months).
Hope this helps, and happy planting!!!
It's never great putting timber directly on soil here - even good quality stuff
Raised beds [especially low ones] are easy enough to make from good quality fencing timber - mine have always been done with that. Batten at each corner or those brackets you can buy in DIY stores.
I live in west central Scotland - not where that photo is...
If you choose the shallower 27cm beds it looks like you’d need about 1.3 tonnes to fill the 3 beds, so depending on how much old soil and compost you have to start them off you might get away with just one tonne bag.
As mentioned above though, the soil will settle over time and they’ll need a good top up at a later stage
Last Spring I removed some turf to make a flower bed, most of the turf has turned into compost, but there's a layer of matted roots that looks perfect for the base of the planter. I've also got bits of wood to lay at the bottom to help with drainage, as the wood decomposes I'm hoping it'll add to the nutrient content.
There's an area of our garden that was a flowerbed, with good topsoil and decomposing bark bits. It's going to be dug up to lay pavers. Some of the good soil from here will make another layer in the planter.
The rest is to be filled with home grown compost, decompressed coir bricks, worm casts (from my wormery), quite a bit of vermiculite (a big bag from Amazon is loads cheaper than smaller bags), and many handfuls of fish, blood and bone meal.
It's surprising when you look around what you can use to help fill your planter. You'll be helping to keep the garden tidy as well.
The basis of my 'recipe' may not be scientific, but as long as there're no contaminants used, and there's plenty of moisture retention and drainage, then I don't see any problem with it.
Cambridgeshire/Norfolk border.
I use old turf etc in my beds when making them, as @Jenny_Aster describes. Mine are mostly ornamental, and up to around 18 inches in height with varying widths/depths [ie front to back] because of the shape of the plot. The ones I did here [ten years ago] were mostly on compacted hardcore/gravel, because the whole back garden was paved/gravelled. The others had a base of plastic or concrete as they were directly on soil/cleared turf.
I wouldn't be skimping on the prep, no matter what timber you're using. Don't underestimate how quickly timber can break down if put directly on clay, with the amount of wet there is, especially if you're in the west.
I live in west central Scotland - not where that photo is...