tomatoes
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Post by tomatoes on Jan 10, 2023 10:27:31 GMT 10
I’m about to set up 4 large raised garden beds and I’m hoping for some wisdom from those who have done this before.
When I’ve done raised beds before (at a previous property) the grass grew up through the bed very quickly. I know it will need weeding, but I want to do what I can to minimise the chance that the beds will be overrun with grass - particularly grass that comes up from the bottom meaning when I try to pull it out it’s either impossible or it rips up all the soil around it.
The beds will sit on an area that currently has grass. If I think we’ll dig up the grass underneath it before setting the beds in place, I’m not sure it would ever happen - the current “to do” list is way too long, and the beds have been in their boxes waiting to be set up for over 6 months (a fence had to be built first, which is finally done).
I have a lot of old cardboard boxes waiting to go to the tip. I could put a layer of them on the grass under the beds. Or I could buy some weed mat. Would these work?
Whenever I’ve used weedmat under stones for a pathway, it only takes a short time before weeds are breaking through. But these beds would have a much deeper layer of soil over the top, blocking a lot more light.
If cardboard would be effective I’d rather use that, as not only is it free, but I need to get rid of it. I just have a very vague memory of something toxic in cardboard that would get into the soil as it breaks down. Does anyone have knowledge of that?
So what are your experiences of raised beds, weedmat and cardboard?
I’d be happy to read if any other tips too. Our beds are quite deep (high) so they’ll take a lot to fill!!
And if possible my preference is to get rid of the grass between and around the beds too, so I’m interested in options for covering the pathways.
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peter1942
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Post by peter1942 on Jan 10, 2023 11:32:15 GMT 10
The cardboard is good for a while depending on how many layers you put in.
I am not sure where you are but I would say that your evaporation rate from a normal garden bed is about a metre a year. By making a raised bed the evaporation rate could climb to about three metres a year so what I have done with ours is put a heavy duty plastic liner in the bed that covers the bottom and up the sides and by doing this you will save not only a lot of water but the beds will stay moist between waterings. You will have to either put a couple of holes in the plastic per bed so that if you do get heaps of rain they will not become waterlogged or at the end of each bed just above ground level insert a plastic 25 millimetre irrigation elbow with a small bucket of gravel around it on the inside of the bed so that if it gets too much water it can get out. On the elbow you can also put a length of plastic tube to regulate the depth of water in the beds to suit the plants you are growing. More water nearer the surface to get seeds going and less water when the plants have a root structure that will reach it. Fittings for the elbow to go into are available at irrigation suppliers.
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malewithatail
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Post by malewithatail on Jan 10, 2023 12:13:42 GMT 10
1) Destroy the grass under where u want to put the beds, using a brushcutter to take it down to dirt.
2) Place black plastic sheeting under, out say 12 inches from the edges.
3) Thick, at least 6 inch, layer of compressed cardboard, or newspaper.
4) Thick layer of cow poo.
5) Thick layer of soil or planting mixture.
6) Good watering in.
7) Let it all settle for a while.
8) Plant out and mulch heavily with straw.
We have had good success with using old tractor tires with the side cut out and the uncut side placed downwards. The dark gives some degree of frost protection as well.
Shadows occur in areas where a dark sucker cannot reach. Shadows are caused by opaque objects blocking the suction of a darksuckers.
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dirtdiva
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Email: cannedquilter@gmail.com
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Post by dirtdiva on Jan 11, 2023 21:31:30 GMT 10
Your vague memory of cardboard controversy is if the glues and chemicals used to produce it leech into the soil. I personally have used cardboard with great success and have seen no studies or evidence to stop me from using it. Newspaper also works. I personally do not till my garden beds but rather top dress twice yearly. By doing this I do not redistribute the weed seeds in the top few inches of soil which is where most of your weeds are going to come from. The system MWT uses above should work great.
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Post by spinifex on Jan 12, 2023 17:52:51 GMT 10
grasses that produce runners (stolons) such as Kikuyu and couch are determined and strong little invaders. They will not only pierce lighter grade weed mat and plastic sheet and definately cardboard which will rot away within months BUT they can find hidden little nooks and entry points in the sides of raised beds or the floors - which means drainage holes and any corner joints that are not 100% tight fitting can let them in.
Either nuke the grass with glyphosate AND a pre-emergent herbicide - something like simazine (sells as Bantox in some garden centres)- out to a perimeter maybe 30cm out from the base of where the bed will be sited and keep it nuked to bare earth with the simazine.
Or ... try and build the raised bed with a solid floor and a 10cm plus air gap under it - and nuke the soil below with simazine.
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rosebud
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Post by rosebud on Jan 12, 2023 18:10:31 GMT 10
Spinifex, you beat me to it. I agree with everything you say. I have put raised garden beds on a couch lawn with cardboard as a base, and have found couch runners coming up one metre. I am about to spray around the base of the raised bed to stop the couch because the couch thrives on the water which runs to the bottom of the bed and out the sides.
In my shadehouse I used a weedmat that landscapers use. I don't know the name of it, but its like a pink felt and very effective. It was available from Mitre 10.
The reason that weedmat under gravel doesn't work so well is that the stones put holes in the weedmat. Also weeds can sprout nearly anywhere, even on top of weedmat. Look at the weeds between pavers. You'd never get a decent vegetable to grow there.
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tomatoes
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Post by tomatoes on Jan 13, 2023 0:21:02 GMT 10
…. In my shadehouse I used a weedmat that landscapers use. I don't know the name of it, but its like a pink felt and very effective. It was available from Mitre 10. The reason that weedmat under gravel doesn't work so well is that the stones put holes in the weedmat. Also weeds can sprout nearly anywhere, even on top of weedmat. Look at the weeds between pavers. You'd never get a decent vegetable to grow there. Are you saying that this pink weed at manages to keep grass away? |
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rosebud
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Post by rosebud on Jan 13, 2023 11:29:24 GMT 10
I've had the pink weedmat in for about 12 months. On the pathways only I put plastic underneath to stop the gravel from poking holes through the weedmat, then covered the whole lot with green shadecloth to further protect it where I walk. So far, so good.
Previously, I used a non-woven black weedmat from Cheap as Chips which disintegrated, especially where exposed to the sun. To be fair, I just looked at the roll I have left and it does say, not UV resistant.
There is a bit of couch along the edges of the pink weedmat, but none at all coming through.
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tomatoes
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Post by tomatoes on Jan 13, 2023 22:58:00 GMT 10
Thanks for all the suggestions
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