Scottish Rock Garden Club Forum
Memorable Topics – Threads and posts that are just too good to lose => Plant Information and Portraits => Topic started by: annew on February 16, 2012, 05:55:19 PM
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I’ve had some requests to describe how I made my 2 new plunge frames, so I hope the following will help.
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Despite being a Yorkshire person, only the slabs used for the base were recycled, all the other materials were bought specially. I don’t think my dad would have approved. He would have used pallet wood and old window frames, I think!
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The frame base is made of concrete paving slabs set on edge, sunk 15cm and packed around with soil, then tied together using strips of copper piping, hammered flat, and bolted to the slabs. Do not try to drill into the slabs closer than about 12cm from the top or they will break. If you do break one, stick it back together with superglue and drill lower down. That’s what I had to do. (Lesson 1)
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The sides of the frame are lined with polystyrene sheeting to help insulate the frame, and also to absorb some of the expansion, should the contents freeze.
The base is lined with porous fabric to keep worms out, then 15cm of large gravel to prevent capillary absorption from the groundwater. Another sheet of landscape fabric tops that, and then the sand is placed on top. I used ordinary sharp builders’ sand.
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To construct the supporting structure for the lights, I used 75x50mm timber for the 2 vertical king posts, 35x35mm for the 8 diagonal braces, 50x50mm for the ridge, and 150x20mm planks for the sides, all tanalised.
First the 150mm wide planks were bolted to the sides of the frame, using coach bolts and nuts. They stood proud of the upper edge of the slabs by 30mm.
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The king posts (cut with a v-notch at the top into which fitted the ridge, positioned diagonally), sitting on the top edge of the end slabs, were attached to the slab using an offcut of timber. The ridge pole was then screwed into the v-notch in the king posts.
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Next came probably the trickiest bit for a beginner woodworker like me. The diagonal braces are fitted between the side planks and the ridge pole. They are positioned in line with the king posts at the end, and to come directly beneath the join between the lights, 8 in total.
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Before fitting, the timber has a narrow groove routed out about 8mm from each side on what will be the upper surface, to discourage rainwater from seeping across from the gap between the lights down into the frame beneath. The bottom end of each brace must be cut to fit in the corner between the side plank and the top of the slab, and the top end cut to fit snugly against the underside of the ridge pole.
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A spirit level must be used to make sure the ridge is not pushed up or pulled down or the lights will not open and close properly (Lesson 2). This is REALLY fiddly, and is ideally done with an extra person to help. A mitre saw was used to do the main cutting, and a belt sander to fine-tune the angles. Keep all the braces marked with their positions and cut them all to size before permanently attaching any (Lesson 3).
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When you are happy that they all fit properly, they are screwed to the side planks and ridge, countersinking the screws.
Finally, the top edge of the side planks is beveled using an electric planer or belt sander, so that it carries on down the angle of the diagonal braces.
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Now for the lights:
The lights (covers) are made of 700mm wide, 10mm thick double-wall polycarbonate sheeting from roofing suppliers. Hinges are the loose pin type as I need to remove the lights in summer and replace them with shading material slung over the ridge pole and weighted down with battens. The trick is remembering where you put all the pins when you need to put them on again (Lesson 4). Also, each light needs to be permanently coded so that it goes on in the same position every time, or the hinge halves won’t match up (Lesson 5).
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2 kinds of edge mouldings were used for the polycarbonate sheeting: The U-section is used to seal the cut ends of the sheeting, and is applied over porous metal tape, which is called teabag tape. The side with the ridge along is used for the upper surface to deflect rain from the gaps between the lights.
The F-section is used for parts where I needed to attach hinges etc. The flap part can be cut off if necessary to leave a deep U shape and a flat strip, which are needed later.
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Cut the polycarbonate to size. The lights should overhang the ends of the frame by about 80mm. I had to take some off the width because my frames were too close together, and when the lights were all raised there became too little room between them to walk along (Lesson 6). Tape the cut edges and apply the u-section plastic moulding, mitering at the top end.
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To attach the hinges to the top of the lights, first I attached the F-section along the top edge, mitering into the corners. Hinge postions were marked and a single pop rivet is applied to the part holding the polycarbonate, to avoid the moulding from being pulled off the light.
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One half of the hinge is then attached to the flap part using small countersunk machine screws and nuts. The rest of the lights are constructed in the same way, 2 hinges per light.
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Before attaching the lights to the ridge, the attachment points for the stays must be fixed. The flap part is cut off an 80mm piece of the F-section moulding, and the resulting deep U-shaped piece is used to attach the stay to the lower edge of the light. It is slid into position in the centre of the lower edge, and rivets applied from upper and lower sides, into a channel in the polycarbonate, at each end of the moulding piece to anchor it to the light.
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Now the aluminium sections come into play. A 25mm piece of the wider aluminium is cut and the cut corners rounded off. A 6mm hole is drilled through the 2 sides towards one end, and 2 smaller countersunk holes in the bottom of the channel. This is then riveted to the piece of moulding you have just attached to the light, so that it is on the underside of the light and the holes in the sides are towards the lower edge of the light.
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You will need to use a spacer to apply these rivets, as the nose of the rivet-gun will not fit into the channel (Lesson 6). I used a 50x10mm piece of flat aluminium with a 2mm hole drilled at one end. The long narrow part of the rivet goes through this, and then a small nut before inserting it into the rivet-gun. The thicker part of the rivet is then pushed into the predrilled holes and the rivet is applied in the usual way.
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Tea-time, more later. :)
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Will u build me some please? They look 'the business'. We are down the road!
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Truly impressive Anne. When you've finished at Ron's you can come a bit further down the road
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Anne - that's tremendous; all the detail is so valuable. You should write it up for the Journal, or as an article for the opening section of the website. Another project to fit in with the prospective tufa garden. It would be good to have such a plunge bed to help increase some of the nursery plants, especially bulbs (and snowdrops!). Up to now I have either grown plants in the garden setting or from seed, but a plunge like this would allow much more control over watering and pests.
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Its amazing Anne. Joking apart it really is what I envisaged as the ideal for my potted plants. I'd like to see someone better it! Now can I follow your instructions .. although they are thorough I'm not so good :-[ :-[ :-[. Will certainly be trying though. Thank you!
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What do you consider each one cost Anne?
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Anne that's brilliant and to have it showed with so much detail is perfect. Better than my effort that blows away every time its windy.
Is Aberdeen to far to come ;D
Angie :)
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Will u build me some please? They look 'the business'. We are down the road!
Ha!! Judging by how long it took me (8 weeks), you couldn't afford me!
Next bit...
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The next part definitely requires 2 people.
The hinge halves are put together and the pins inserted. The centre point of each light and where it should be placed on the ridge pole are each marked. Each light, depending where it is on the frame will need part of the flap on the F-section removing to clear the diagonal braces and king posts. I used strong snips, and a power file.
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The completed light is offered up to the ridge pole, matching the 2 marks. The roll part of the hinge just hooks over the outer corner edge of the ridge pole. The other half of the hinge is then screwed to the ridge. Keep checking that the lights stay away from their neighbours by about 5-6mm all the way down so that they will not catch on each other. The other lights are attached in the same way.
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Best I've ever seen Anne. Last a lifetime. Congrats!
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To complete the stays, a 300mm length of the narrow aluminium section is cut and both ends rounded off. A 6mm hole is drilled at each end from side to side, at about the centre point of the circle you have made of the ends of the section. This will act as the pivot. One end is attached to the piece of wide aluminium section on the lower side of the frame light, using a 5mm diameter machine screw and locking nut.
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The light is lowered into the closed position. A piece of the wide aluminium section is applied vertically under the light against the side plank, until it just comes short of touching the light. The stay is then laid along it and the position of the bottom hole marked onto the wider piece. The wider piece is then cut to 10mm below the point where the hole in the stay matches up to, and the corners rounded.
7 or 8mm holes are then drilled through the sides of the wide piece at the marked point, at the top, and half way along. 2 smaller countersunk holes are drilled in the channel so that the piece can be screwed to the side plank. To do this, the bottom holes of outer and inner stay are aligned and a nail or pin threaded through, then the wider section is placed against the side plank, and held in position while the nail is removed, when the screws can then be drilled and applied.
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The ridge is capped with a length of PVC pond liner, stapled to the point of the ridge.
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For the triangular end lights:
Cut a piece of polycarbonate to shape so that it overlaps the end braces, tucking under the lights, with a flat top.
Tape and edge the piece with U-section moulding along the sides and top. For each end, cut 2 pieces of wood the width of the slab top, to fit between the king post and the side planks. Screw into position.
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Using a piece of the F-section moulding with the flap removed, attach 2 hinges to the triangle, drilling and bolting right through the moulding and sheeting together. Edge the remaining part of the triangle base with U-section moulding.
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The triangle is then offered up to the end of the frame and the other half of the hinge screwed into the wooden bearers. A simple catch for the top of the triangle can be made from a small block of wood, and a short piece of the flap removed from the F-section moulding, loosely screwed to the block so it swings freely.
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I live in a windy place, so I have made extra precautions to prevent the lights being wrenched off by the wind. This is simply a length of webbing long enough to go over the lights when in the open position, with half of a quick release bucle at each end. The other halves of the buckles are screwed to the end slabs, with a short length of webbing. It is quick to fasten and undo. I tend to leave it on every night, just in case the wind gets up – I don’t want to have to go down the garden in the middle of the night!
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Finally, it is useful to have a long prop for the lights for when you want to work under them.
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This can be made from a 30mm wide x 800-900mm piece of timber. At the bottom end, on the back, a short piece of the narrow aluminium channel is attached, drilled from side to side as usual. This can be pinned to the top hole in the bottom part of the stay.
At the top end I used 20mm square section aluminium, cut 80mm long. This is screwed to the front of the wood so that when the narrow part of the stay is inserted through it, just enough of the stay pokes out so that a pin can be pushed through the stay to stop it lifting out.
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I attached the pin to the prop with a short length of chain and a staple so that it wouldn’t get lost. I made a separate prop for each light. They are narrow enough to store on their sides on top of the slabs inside the frame when not in use.
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Right then, lads and lasses, for homework I want you all to have a go, and please tell me any refinements you come up with, because I’ll probably be making some more, since these 2 are already full up.
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Are you sure you can't come and refine them in situ here. I always got E- for homework!
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Practice makes perfect, Ron. ;D
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Anne:
Are those espaliered fruit trees in the background.
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Anne,
that's very good, nice detail and pitfalls explained. Well done. :) :) :)
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Thanks Anne for taking the time to download all the pictures and explaining everything, it would have taken me 8 weeks to get these instructions onto my computer so well done.
Angie :)
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Great topic Anne. You have certainly inspired me to have a go. ;D ;D
Now where did I put that big hammer :P
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Ron, you have to remember my husband's motto - 'never use a nail when a 6" screw will do'.
Arnold, yes there are espaliered apples and fan-trained plums etc.
Also an awful lot of mess left over from last season, since I spent all my time constructing these babies instead of tidying up.
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Anne when I see how much work you have done and how much money you have invested I wonder what are the advantages of a pluge bed made that way instead of a plunge bed in a tunnel?
I found the tunnel easier to build and you are out of the rain all the time while gardening.Even if I am a continental guy I made it the yorkshire way:from the frame under the tarpaulin of a lorry.I got a 2,5m X 8m tunnel for the price of the scrap metal and the sheet of plastic.For good ventilation I can open the front and the back(yes made from pallet wood ;)) and roll up the sides for about 60cm.
it doesn't have the beautiful look of your construction but it may be a cheap and easy alternatve.
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Hi John, I would have to get planning permission for a tunnel, I think. I already have 3 greenhouses in quite a smallish garden, and my mini-nursery is in the part of the garden behind my neighbours' house, so it would be intrusive to them as well.
Respect to you for your Yorkshire approach!
I'll try and tot-up how much the 2 frames cost to make.
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Anne Wright, you're brilliant. Of course much too complicated for my style of DIY which hasn't improved much from the Neolithic :-[
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David, it would be even better made out of stone. ::)
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Well, I added up my outgoings for the plunges. The cost also includes materials to make stays and props for 22 other frame lights, and I have lots of spare bits like extra screws etc left.
(Deep breath) £680
Well it's cheaper than a certain snowdrop.
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Is that for each bed Anne?
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No, the pair. Including all the sand and gravel. But not the plants.
I don't buy expensive handbags either.
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Eh, thats not too bad Anne. :) Given the quality I would have thought a lot more. Should last a while.You'll be able to judge from how your plants perform in these new structures. What orientation do you have?
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Sure Anne...daff as a brush my @#$....
These look spectacular and should allow some bit of growing to be going on. I'd love a range of these....
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They are oriented about W-E. End on into the prevailing wind.
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oh!
mmmm. never mind, see your thinking , great. sure thy'll be fine. Will u b @ driffield anne?
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How are the new beds performing Anne?
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So far so good, but I need more. ::)
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JULY 2013, the frames are still going strong. The butyl capping strip needs a batten on it to keep it down, as the staples ripped out.
Frame number 3 almost done. Frame number 4 before this winter, but probably on a wooden base rather than slabs, as the plants inside won't be plunged.
I haven't ever removed the frame lights, so the hinges could be ordinary ones, I didn't need the removeable-pinned ones. They were to allow the lights to be removed in the summer.
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Fantastic job Annew!
I've just "scored" a load of (mostly) full sized clear polycarb sheets on freegle. My plan is to use it to;
a] make a temporary (as in I'll erect it in autumn for the winter) covered area over the rockery area. Mostly for the benefit of succulents, I also have a few other plants that I want to try there too.
and
b] replace the roof on my shed (about the size of a single garage) with it to improve the light for the plants that are in there over the winter.
Do you have any problems with moisture getting between the layers of the sheet - if it does do you consider it an issue?
Thanks for taking the time to do this post.
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No, so far they have stayed moisture free in the gap between the sheets. The cut ends were sealed with what they called tea-bag tape, a kind of perforated foil adhesive tape, before the plastic mouldings were applied.
Good Luck!
Frame number 4 turned into a full scale greenhouse for my hepaticas/tomatoes...
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For the polycarbonate sheets used to replace some glass in the greenhouses, Ian used an aluminium tape sold for the purpose, to seal the open ends.
I would think it is not the best idea to leave them open - old sheets of this material that we have lying around for frame covers have got quite a lot of algae etc in the open spaces.
Easy enough to wash that out from a "loose " sheet, but not from one fitted in a frame or greenhouse. :P
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Thanks for the answers . I was going to be a cheapskate, but I'll buy the proper stuff now.
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As a rough guide, I think 45mm tape is the size for 25mm sheeting.
Plenty available at good prices via Amazon or Ebay ( edit to add- of the solid and perforated types) so your bargain sheeting is still going to be a "steal of a deal" :D
I'm a great believer in recycling!
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I'm a great believer in recycling!
Me too! The local freegle group is very active around here. 90% of my plastic pots come from there, and here is my potting bench which I "won" on there.......................
(http://img20.imageshack.us/img20/2369/dsc2351g.jpg)