Scottish Rock Garden Club Forum
General Subjects => General Forum => Topic started by: Alex on April 12, 2009, 04:53:25 PM
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Hi,
A quick question for those that have plunge beds (most people probably!) What do you line them with? I now have a new plunge, but it is just metal sides and a corrugated iron base, so I presume it needs lining, but with what? I have found an old thread on this forum in which plastic pond liner is mentioned. Is this the norm? Would you just make some small holes for drainage if so?
Any help welcome!
Many thanks,
Alex
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nothing lines my aluminium plunge
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I lined ours with old plastic sacks cut to make them into sheets. They overlap but allow seepage of water, if necessary.
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Thanks, both. Mark, doesn't the sand leach out when you water into the plunge?
Alex
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now yes because one plunge isnt very full but the two that are filled no problem so far
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Alex,
I suppose construction of one's plunge bed depends on what it will primarily be used for.
It is my *most* important garden "tool"---something I could not live without---and the first thing I would again build when I change gardens. I have better success overwintering plants in the plunge than in cold frames. And a plunge bed is a snap to build.
I use mine primarily for overwintering plants in pots, including small first year seedlings. Also to grow on bulbous plants from seed until they are large enough to plant in the open garden. My current plunge is in full sun, on a flat site, where water does not accumulate for any extended periods of time. I would like to have another one in light shade.
It is a large rectangle, outlined with railway ties, filled with sand to a depth of about 12" (to accomodate deep pots). Not lined in any way (not sure why folks would line theirs????) Exposed to the elements. Never covered.
The only maintenance ever necessary is to top up the sand every few years (as I tend to steal it from there for other projects).
Plunging in sand is easy (although sand must be moist or else it collapses on itself when plunging).
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Woo! Kristl ... now those are plunge beds! 8)
Some of our psand plunges are a bit close to trees and a hedge and, even though raised above ground level, we do have a bit of bother with those roots coming up into the plungs.... so I suppose a lining underneath mighthave been a good idea.... but we give the roots a good dig out every few years and it's not that big a problem. not sure why sides would need lining either, really :-\
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Thank you Kristl, that is a really excellent plunge!
I'm afraid I have caused confusion by carelessly stating bed when I meant staging in the original post - as in greenhouse staging. Apologies for my mistake, but hopefully the question makes more sense now.
Sorry again - must not have been thinking.
Alex
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hopefully, Janis Ruksans will add to this post....because he sent me this picture of his greenhouse a couple of years ago...i believe he said his boxes were lined with styrofoam sheets on the sides---obviously for extra cold-protection in his climate---which may not be an issue for you, Alex. I can't remember if the soil in the boxes goes all the way to ground level, or if there is a "false bottom" somewhere....
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I answered as for a staged plunge in the greenhouse. The outside plunges have the weed stopping membrane underneath. They are a tiny fraction of the size of Kristls'.
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Kristl,
How in the world do you get to pots in the middle of those large expanses. :o I can just imagine spotting weeds in there and then having to work out how to clamber over the other half million pots to get to them.
I think one of these years I must do something along these lines..... getting far too hot and dry here in summer now for many things. ::)
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Kristl,
How in the world do you get to pots in the middle of those large expanses. :o I can just imagine spotting weeds in there and then having to work out how to clamber over the other half million pots to get to them.
Ah, Paul....it's my very logical, brilliant mind and practical spirit that does it 8)
But truth be told, I don't ever need to get to anything in the middle....everything more or less comes out every spring and goes back in the fall.
I have already arranged them logically as to what needs to come out first (by sale times, by flowering, by stress etc). The pots that stay for the summer are in their own (shadier) sections in the rear, closer to my building, where they are easily accessed, if necessary.
I've actually arranged the plants in sections, as you will notice, with walking rows in between, so that I can get to everything if need be from one side, or the other.
When I plunge again in the fall, it is with the same forethought as to what comes out in the spring and when, and what stays.
Next week I will un-plunge the very first section of alpines and succulents that need to be tidied up & prepared for my first sale of the year, on Mothers Day and thus, I progress, until the bed is mostly empty.
Needless to say, the weeds that *do* appear, are a snap to pull out of that lovely sand. And when it is empty I routinely just rake it lightly to keep it clean (and feel very Japanese & spiritual while I am doing it ;)
What *is* problematic is leaving plants in the plunge for too long (years) ---with them rooting down through the pots & deeply into the sand. In the last picture, you will notice a batch of very tall plants in the left rear corner---these are seedling woody species that had to be literally excavated last fall, as their roots went several feet down.
And I forgot to say that in the summer, when the plunge is mostly empty (with the exception of seedling pots and bulbous species)--this is where the fun happens--because the sand bed then becomes the place to make free-form troughs. The sand is wet down, the shapes are made, and the hypertufa added. They are then left there to harden & cure, and lifted out when ripe. Nothing could be easier.
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I've used weed mat and also thick old tarpaulin as a base to my plunge beds (outside) and still the roots of the damn eucalytps come up through.
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the important lesson is to build the plunge bed as far away as possible from any woody species. mine is over my septic bed---a good use for a mostly unusable space.
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A quick question for those that have plunge beds (most people probably!) What do you line them with? I now have a new plunge, but it is just metal sides and a corrugated iron base, so I presume it needs lining, but with what? I have found an old thread on this forum in which plastic pond liner is mentioned. Is this the norm? Would you just make some small holes for drainage if so?
Some 25 years ago, in preparation for building a raised bed for bulbs, I looked for guidance, and found it in the SRGC bulletin. The particular issue was, to dig out under the raised bed and put in "drainage" or not. The advice was not to do so, regardless of your soil. If you had fast-draining soil, no need for "drainage" at all. If you had poorly drained soil, digging out underneath and putting in "drainage" would merely create a sump to hold water and keep the bed above unduly moist.
Mutatis mutandis, the same applies to plunge beds. The plunge medium (usually sand) should be in direct capillary contact with the soil underneath. If the underlying soil is reasonably well-drained, then the plunge bed can be a simple excavation filled with sand, but if poorly drained, you really should have the plunge medium above grade for drainage.
My own experience revealed that perhaps the most critical factor is making sure the walls of a raised bed should be able to resist the lateral force from the weight of the soil or sand filling it.
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the important lesson is to build the plunge bed as far away as possible from any woody species. mine is over my septic bed---a good use for a mostly unusable space.
kristl, that bed is great, and i definitely should have something like this, on a smaller scale...lol
keeping it away from trees would be a desirable idea for many kinds of beds, unfortunately i have no area that is any significant distance from large, established, native, woody species, even in the middle of my largest sunniest clearings there are plenty of poplar suckers, and no doubt all sorts of roots ..i think i will just always have to be nipping off, pulling out and hacking at suckers and roots...
just today i clipped probably a couple hundred poplar stems--saplings from a 18" tall to 10-12 feet; there are many many more to go, plus many that are too big for clippers, and i will be getting the chainsaw to work on those ones.. (these arent all in the 'yard' and 'garden' areas, some are around the edges where i hope to expand the mowable zone for the express purpose of keeping the forest at bay, and some are within the edges of the bush, where i want to thin natural seedlings, keep some areas of forest more open, regulate which species are present in what numbers etc...)
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Can I follow up by asking what kind of sand people use? I was planning to use some coarse builders sand with particle size up to about 5 mm (but there is quite a lot of finer stuff in there too.
Thanks for all replies so far, also.
Alex
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Cohan, Unless you have serious issues about chemicals, cut the suckering woody species close to the ground, leaving exposed ends of 1-2" and treat (paint the stumps). I easily got rid of huge colonies of unwanted suckering woodies in this way---the stumps were also dead in short order.
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Hi:
Our conditions are different, and for most of you could be regarded as very mild. We have used for many years plunge beds made with brick on their sides walls. These walls were lined in the inside with 1 in. or 2 in. styrofoam sheets. We used 16 cm. clay pots and the plunge material for most species was a mix of very coarse sand and sterilized soil. For plants demanding warmer conditions, we used charcoal as the plunge material, that traps a lot of warmth.
The method was good but we had a couple of catastrophic virus outbreaks that spread throught the plunge material with waterings. Besides, keeping the pots tidy at the same level was a chore. In any case we used it for some 18 years until we shifted to the current method, that proved a lot better under our slight frost conditions.
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Cohan, Unless you have serious issues about chemicals, cut the suckering woody species close to the ground, leaving exposed ends of 1-2" and treat (paint the stumps). I easily got rid of huge colonies of unwanted suckering woodies in this way---the stumps were also dead in short order.
That worked on a balsam poplar tree that I chopped down and produced a forest of suckers all over the garden. I dosed them in the autumn and it was no more.
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Cohan - If you decide to paint the stumps with any chemical that is volatile (i.e. produces vapours) then it is a good idea to immediately cover the stump in plastic and close tightly with an elastic band.
A friend treated a stump with 2-4-D without the plastic, within a week a nearby magnolia had rolled leaves on all branches from ground level to 1 metre higher. That probably was not so good for it but the magnolia did survive, just shows you what these chemicals can do.
Another friend treats Acer rubrum this way but she drills holes first and fills them with a bit of concentrate. That does the trick very well.
johnw
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Alex,
re Sand.
A counsel of perfection, would be to use horticultural grade, washed, lime free sand.
This is available in bulk, delivered free of charge, from various horticultural suppliers.
(if you want a 'name' let me know).
In bulk, it is less than 1/2 Garden Centre prices.
Builders sand from your local builders merchant, might be ok for your particular purposes, but it can be a bit of an unknown quantity.
(re lime content, and various salts).
It will, however be alot cheaper.
You will need ALOT.
I needed 1.5 tonnes for a 10' x 12' greenhouse with plunge staging on both sides.
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Thank you Giles, I will take your advice and get horticultural sand.
I have also found what seems to be an excellent material to line the staging with, it is a weed suppressant which is water permeable but of course won't allow sand through. We shall see.
Alex
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Cohan, Unless you have serious issues about chemicals, cut the suckering woody species close to the ground, leaving exposed ends of 1-2" and treat (paint the stumps). I easily got rid of huge colonies of unwanted suckering woodies in this way---the stumps were also dead in short order.
tks, kristl--i do have issues with chemicals,lol--but not averse to evaluating individual cases--since i am not always pure of heart enough to allow unfettered nature to reclaim my home and yard fully...lol
so what sort of chemicals are these?
i'm not sure if it would work in my case, since the suckers are coming from live trees which are all around the 'yard' part of the property in all directions, and scattered through the yard as well---native aspens and balsam poplar; i am gradually reducing numbers a bit--pushing the bush line back a bit farther where young growth has been pushing forward, and getting rid of some of the aging poplars in the yard, but i think there will always be trees in suckering range of most if not all parts of the yard...
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On greenhouse plunges I noted that Alex was using corrugated iron as a base can anyone suggest a lighter alternative please?
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David,
My staging came with galvanised metal sheet.
It's not like 'corrugated iron' in the sense of what was used for air raid shelters and the like, and is very light.
Not much heavier than heavy duty corrugated plastic.
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Thanks Giles, is your base rested on brick/block piers please?
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Each 'bed' is 1800mm long, 780mm wide, and 175mm deep.
It has aluminium sides, and detachable corrugated metal bottom.
Each 'bed' required 270 kg of sand to fill.
It stands on braced aluminium legs, on a solid concrete base.
I didn't bother lining the bed - and no sand has worked it's way out (yet).
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Thanks again Giles, can you tell us the name of the manufacturer?
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Hartley.
They make shallow 'normal' staging, and this deeper 'plunge' staging.
I think they will manufacture the staging to a range of sizes.
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My set up is very similar to Giles's, and has the same galvanised metal sheet on the bottom, carelessly and incorrectly termed corrugated iron by me. I've filled one plunge out of two, and am enjoying the benefits of not watering every other day.
Alex