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Rocks/Rubble in a raised bed?
Daithi29
Posts: 71
Morning all. Hope everyone is doing ok during these crazy times and staying (and sane!!).
So I dug out a massive conifer that was in a double length raised bed last weekend, have loads of seedlings to be planted and wanted to see about filling the bed. I have a lot of rubble and smashed crocks that I was going to chuck out, but should I just throw it into the bed before covering with top soil? I've already mixed in some sand and gravel (not much) but will eventually get compost and topsoil once the restrictions have been lifted here. Is it ok to just mix in the rubble/crocks or should this all be placed at the bottom of the bed? Thanks all
So I dug out a massive conifer that was in a double length raised bed last weekend, have loads of seedlings to be planted and wanted to see about filling the bed. I have a lot of rubble and smashed crocks that I was going to chuck out, but should I just throw it into the bed before covering with top soil? I've already mixed in some sand and gravel (not much) but will eventually get compost and topsoil once the restrictions have been lifted here. Is it ok to just mix in the rubble/crocks or should this all be placed at the bottom of the bed? Thanks all
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Posts
If it's a good couple of feet or more, then it would be ok. I'm not a huge fan of using rubble at the base of beds if they're shallower, because it can sometimes act as a sump in wet weather, especially over winter. It then means that plant roots can be sitting in water for too long.
If you do use it, it's useful to put a layer or membrane, or similar, over it to prevent your soil filtering down through it too much. Raised beds tend to settle and sink a bit anyway, so it helps avoid too much of that,especially early on.
I live in west central Scotland - not where that photo is...
You just need to mix the clay with other organic material to make it a better medium for growing.
I live in west central Scotland - not where that photo is...
A fairly thin layer of gravel etc isn't too big a problem, ie a few inches, and that can be deeper if the bed is also deeper, but without a barrier [membrane] the soil level will sink quite rapidly, and by quite a lot, as it all settles and works through gaps. Especially with winter rains etc. The bigger the pieces of rock, the bigger the gaps. Not a problem if there's plenty of soil for adding, but it makes more expensive to fill.
It's easy enough to add more organic matter, but not just compost, unless there's already a good amount of soil in the bed. If only compost is used, it's not sufficient for long term planting. Same idea as planting in pots - compost's fine for a season but not longer than that
I live in west central Scotland - not where that photo is...
It's made from 18mm thick loglap which i lined with polytunnel grade polythene .The corners were 4"x4" wood and the 1m lengths sections were screwed to 2"x2" battons. I then put polythene bag covered 1" thick struts across every second pair to prevent it moving. However I only did this at the top thinking the rubble would prevent movement at the bottom.
A bed that length would need supports front to back every so often, as well as posts. A post at each corner wouldn't be enough to hold the kind of volume a bed that size would contain. As it's on concrete, you can attach posts to that with brackets and bolts.
My raised beds only have a post at each corner if they're about a metre at most. Anything longer has additional ones concreted in. This bed is about 3 metres long, and about 50 cm in height at the highest end [ground slopes]
I live in west central Scotland - not where that photo is...
(It looks as if some password got added to your username by mistake. Does one of them need changing?)
You can help rubble not settle by using 'clean' stuff ie no earth, so it will move less. You could also add or mix in some 'sharp' gravel if you have some around, or if the whole thing can be topped up even left over drive-type gravel that will 'flow' as it settles and just top up the top layer (Which would be compost in a raised bed).
Either way, as you say, the basic structure needs to be strong enough.
@Fairygirl
Loglap is the curved cladding that makes your shed look like a log cabin. Normally the top one from featheredge, shiplap, loglap options around here. 18mm sounds like a fairly heavy duty version.
Your raised bed design interests me - how long do you find a wooden pillar like that concreted in to the ground directly lasts?
One of my fencing ground rules is that I never concrete wooden posts directly into the ground as they will always rot around or just above ground level in a short time (7-10 years), then I am then left with a bloomin' great lump of concrete where the new post needs to be
It may be a "horses for courses" thing. I usually construct fences designed to last 25-30 years for long term rentals, or be removable relatively easily. My raised beds are done with knockerposts usually, which I put a postsaver on if it needs to last.
Ferdinand
If you angle all the concrete to encourage water to run off, that helps too. My beds are all lined with heavy duty polythene as well, and it runs over the concreted surrounds wherever possible. I only use good quality, treated posts as well. We have huge amounts of wet weather here, so shortcuts are pointless.
Re the loglap - I wondered if it was that stuff, as a neighbour has clad an outdoor shed with it. I couldn't follow how the bed had been constructed though, which was the main problem.
I live in west central Scotland - not where that photo is...