Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: ArnoldT on September 15, 2010, 05:35:42 PM
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I have seen plunge beds in many of the images posted here. Some look like pure sand and other look like a collection of whatever was left lying around.
Any suggestions about about fill used for a plunge bed.
Thanks,
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Arnold I am glad you asked this question I also would like to get some advice too.
Dont like to hijack your topic but I was also wandering what depth the plunge beds should be.
Angie :)
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Some of our plunge beds look a bit scruffy, because for the Erythroniums we are growing in them we have been covering over (those sand plunges that have the bulbs in pond baskets plunged up to the rim) the beds with a mulch of composted shredded hedge trimmings. This helps to keep down the growth of mosses and liverworts and aslo helps keep a moist atmosphere around these bulbs, which would really prefer a woodland situation.Whether for inside a glass house, in a frame or outside, any plunge bed should be as deep as possible. ...and sand is without doubt the best medium for such a bed.
In our glass houses the plunge benches are really too shallow but we are constrained by the need to have a double layer so we cannot have the very deep (at least fifteen inches/ approx 38cms) plunge benches, which old style alpine houses used to have, usually made of brick and providing a great place for plants in pots to live!
Outside, whether in the open or in a frame then, again, the more depth the better- this will keep a steadier temperature and moisture level around the pots .
It is best if the sand can be in contact with the ground below since this will greatly aid in drawing moisture evenly through the sand.
Hope this is some help.... it works for us!
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Sand for the plunge beds in the greenhouse, I have read in some old posts that you can't use builders sand, I was just going to get some sand from our local quarry .
Also if I heat the greenhouse do you need to put warming cables under the sand.
Angie :)
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Builders' sand is fine , Angela. You want a coarse sand anyway, the very fine stuff tends to get "caked" too much.
Warming cables are a good idea..... Ian has 'em. They hardly ever go on, they're on a thermostsat just to be able to protect the bulb pots from being frozen right through in the worst of the cold weather. In a mild winter they may never run at all but it is good to know you have the option to either protect from frost or even raise the temperature a bit higher for some plants or when propagating.
I think there's a thread here somewhere for warming cables.... I'll go have a look......
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Some of our plunge beds look a bit scruffy, because for the Erythroniums we are growing in them we have been covering over (those sand plunges that have the bulbs in pond baskets plunged up to the rim) the beds with a mulch of composted shredded hedge trimmings. This helps to keep down the growth of mosses and liverworts and aslo helps keep a moist atmosphere around these bulbs, which would really prefer a woodland situation.Whether for inside a glass house, in a frame or outside, any plunge bed should be as deep as possible. ...and sand is without doubt the best medium for such a bed.
In our glass houses the plunge benches are really too shallow but we are constrained by the need to have a double layer so we cannot have the very deep (at least fifteen inches/ approx 38cms) plunge benches, which old style alpine houses used to have, usually made of brick and providing a great place for plants in pots to live!
Outside, whether in the open or in a frame then, again, the more depth the better- this will keep a steadier temperature and moisture level around the pots .
It is best if the sand can be in contact with the ground below since this will greatly aid in drawing moisture evenly through the sand.
Hope this is some help.... it works for us!
To illustrate what Maggi means, this is how I constructed my glasshouses.
All the clay-pots are plunged in a yellow sand that is able to hold the moisture for some time and that stays firm enough when a pot is lifted.
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Well, Luc, I have to say that your glasshouses are a treat to see.... so neat and tidy.... very impressive 8)
I haven't found the thread that I mentioned.... must have been imagining things :-\... there are odd mentions but here is a link to a good post
by Gerd K. about an experiment he made...........
http://www.srgc.org.uk/smf/index.php?topic=2496.msg59350#msg59350
For anyone wondering what our system is: The cables are below the pots, set to come on when the temperature at about an inch or so below the sand plunge surface goes down to minus 1 degree C and the heat goes off again when the temperature is raised to around plus 1 degree C.
I had a look in Len Rhind's Bulb Log Index ( what would we do without that man?)
http://www.srgc.org.uk/bulblog/index.pdf and found this.....
http://www.srgc.org.uk/bulblog/log2004/270104/log.html
I am worried to post that because the contrast between our glasshouse and Luc S' one is more than extreme!! :-[
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Wow. Luc I'm envious now.
I don't think soil cables would work here as well. Our lows can get down to 10F at times.
Builders sand may contain some salt. I used Play Sand which is washed and sterilized for use in childrens play boxes.
Must be careful with the overall weight on greenhouse benching. Wet sand can be heavy.
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Maggi,
There is this thread about thermostats on cables?#
http://www.srgc.org.uk/smf/index.php?topic=1098.msg25509#msg25509
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Well done, Mick..... I thought there was something else to be found! :-\
Arnold, of course you are right, for greenhouse staging with sand benches the whole construction needs to be VERY strong and solid.
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My plunges are mostly about 25cm deep, and contain 'sharp sand' from our local dealer (just ordered some more today cost £24 per bulk bag -about a ton-plus vat). Get a look at it first if you can and hopefully get stuff which is not too dusty.
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I think I need a new greenhouse and start right at the beginning again.
Luc I can only say one word and it's WOW :o :o :o :o :o :o , can I move into your greenhouse.
Now I will have to find where to buy, heated cables, plunge beds and everything else I need, can anyone pm with any information please.
Away to have a long look again at Luc,s amazing greenhouse 8), mine is such a muddle :'(
Angie :)
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Builders sand may contain some salt. I used Play Sand which is washed and sterilized for use in childrens play boxes.
If by salt you mean sodium chloride (table salt) builder's sand should be free from it since it causes problems with frost resistance and corrosion of steel. Why do you think there is salt in it?
Cceers
Göte
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I've never used heating cables. My benches are 70cm deep because they stand on the concrete greenhouse floor. That volume of sand gives enough heat-capacity to prevend the pots from freezing
through. In a hard winter, I give some overhead protection with fleeze or air-bubbles plastic.
About the cleanliness. I think this is necessary if you want to control deseases.
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I grow all my bulbs in clay pots in plunge beds - they are only brought under 'glass' (i.e., plastic) when in flower. My plunge beds are 60cm deep. The bottom 30cm of most of them is filled with builders rubble - in one case with wine bottles (empty) - & the top 30cm with coarse, sharp sand sometimes known as concreting sand, quite different to the soft, yellow builders sand. This holds water reasonably well for a short time. I don't think it matters what bulky material one puts in the bottom of a plunge & I recall Bob Wallis recounting how their plunges were filled up with old lawnmowers, defunct TV sets & similar rubbish - veritable time capsules.
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If by salt you mean sodium chloride (table salt) builder's sand should be free from it since it causes problems with frost resistance and corrosion of steel. Why do you think there is salt in it?
Cceers
Göte
I thought that was well. I know applying salt in the winter to new concrete can cause spalling. Salt (NaCl) would be the enemy of the concrete process! I went to a mason's yard and the fellow told me the bulk sand was from the beach and had sea salt in it. I had told him I was going to use it for a plunge bed and to improve drainage in a potting mix. Of course had to explain what a plunge bed was! So I purchased the Play Sand that had been washed and sterilized for use in a child's play sand pit.
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If by salt you mean sodium chloride (table salt) builder's sand should be free from it since it causes problems with frost resistance and corrosion of steel. Why do you think there is salt in it?
Cceers
Göte
I thought that was well. I know applying salt in the winter to new concrete can cause spalling. Salt (NaCl) would be the enemy of the concrete process! I went to a mason's yard and the fellow told me the bulk sand was from the beach and had sea salt in it. I had told him I was going to use it for a plunge bed and to improve drainage in a potting mix. Of course had to explain what a plunge bed was! So I purchased the Play Sand that had been washed and sterilized for use in a child's play sand pit.
In my part of the world, all the coarse sand sold for concreting purposes is of marine origin. I think it is washed before being sold but I am not sure how thoroughly. I have never had any problems with it, though I should add that mine has been in use for 20 years or so & by now will have been well washed.
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I have always used builders sand and buy it from B&Q as the bags are easy to handle.
It gets covered in liverworts and assorted weeds during the winter and spring and I clean it of when repotting and top it up with fresh sand.
I have two beds with heating cables and these worked okay last winter which was our coldest here since we arrived 17 years ago.
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Angie, try www.twowests.co.uk. That's where my plunges came from.
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My husband said that there isn't salt in the ton bags that we get ,he said like some of you have already said it would cause big problems, so it will be nice and cheap.
I could hear him moaning if I had to buy Child's play pit sand, he is in construction and buys sand in a weekly basis.
Thanks for the advice, I ordered the plunges, would have liked to got wider ones but my staging is only 2 ft wide. Bought the heating cables, thought I better be safe than sorry.
I shall post a picture when everything is finished but don't expect something like Lucs, I am still at the learning stage but maybe one day I will have something as amazing as lucs ::)
Angie :)
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My parcel came today from twowests...first thing I thought was I have ordered the wrong thing but no they have to be bolted together I thought they would just come 100" long ::).
Now the hard bit ::) ;D what nice thing can I cook for hubbies tea ;D He can use his new socket set, no point depriving him of that ;D.
Shall post a picture, hopefully soon.
Angie :)
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Crikey, they don't hang about do they? That was good fast delivery.
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Yes Maggi they were really quick and so helpful and delivery only £4.99 .
One thing about the plunge beds it will stop me knocking my pots of the staging, I wouldn't like to count the amount of pots that I have knocked down.
It's only two plunge beds, but it's a start ;D
I was reading on another thread about potting or not re-potting your bulbs every year so maybe I should keep to only two plunge beds. It must be so much work but I suppose worth every minute if you can produce flowers like some members produce.
Angie :)
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He can use his new socket set, no point depriving him of that ;D.
I hope he's not disappointed Angie, it's quite difficult to get the ratchet drive into the corners :( Give him 2 10mm a/f spanners, one ring, one open and he'll be happy as can be ;D ;D ;D
Now just to maKe you scratch your head a bit.....you need to decide if the bent over bits at the top of the plunge face in or out. I go out to maximise plunge space but I've seen others with them turned in the way to save greenhouse floor space. You might also remember that both Diane Clement and myself line the bottom of the plunge with water matting to 1) act as a water reservoir and 2) to stop the sand washing out through the drain holes.
Of course, as supplied, there are no drain holes so your better half can also have some fun with a drill 8)
Martin
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Thanks Martin for the advice. Drain holes I never even thought of that, the water matting is that capillary matting or something similar.
He popped back at lunchtime and I showed him the pieces and before I could say anything he said I forgot I am golfing this afternoon but I shall it done tomorrow. I won't say what I said :-X
I really don't mind as I took one look at my greenhouse and thought to myself it will take me a day to move my pots to get space to move.
Maybe I could do it myself, better not he hates me using his tools. I always forget to put things back in there place ::)
Angie :)
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Angie, the water matting I use is another Two Wests product. It's thicker than capillary matting so you can just soak it and leave it for several days, saves having water tanks and wicks etc like you would use with capillary matting. I use it on my shallow staging trays. Capillary matting would certainly be OK as a substitute under the sand.
Another bit of advice (I'm confessing to all my mistakes here) is to build it in situ even if your greenhouse door is wide enough to move it in afterwards. It's all built hand tight and then all the bolts are tightened up at the end. If you do it in position it will naturally compensate for any unevenness in the floor of the greenhouse so that when it is all tightened up you don't end up with some of the legs off the ground!
p.s this means putting your head under the plunge to get a the nuts and bolts....if either of you can do that without ending up with a sore head you're way ahead of me in skill :'( :'(
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Thanks again Martin. I will show this to my husband and it will maybe make things easier for him.
I have fixed staging in my greenhouse, husband built wooden staging, so hopefully I won't have a sore head ;D
Angie :)
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Here is my plunge bed finished in the greenhouse. Got a bit carried away and started in my poltunnel, most of the plants in the tunnel could stay outside but after this last winter when a lot of the pots were frozen solid I thought this would help a little.
The staging in the greenhouse that was recommended by forum members was perfect. I am really pleased but now I will have to work out how much water the pots will need.
Thanks everyone for the advice.
Whilst doing the plunge in the polytunnel a frog jumped out of a plant, he was only little so didnt give me to much of a scare.
Angie :)
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Wow! That looks really great, Angela....you have masses of super plants there.....the new metal plunges look very smart and you have it all laid out neatly.... even in the polytunnel where we would be messy!...... well done!!
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I'm looking forward to seeing it in person next April, Angie! ;D
If the invitation still holds (and we have transport!)
cheers
fermi
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Maggi I never showed a picture of the other side of the polytunnel, it's like a bomb has went off.
Fermi Looking forward to you coming, accommodation here if needed, but no cooked breakfast, I burn everything. Can't cook, won't cook ::) there is always porridge ;D hope you will have the time to visit my friends garden, Bill and Helen are SRGC members and i was down yesterday and there garden was looking really good, well worth a visit, plan it for lunch time as Helen is a good cook. I can't wait to next April to meet everyone.
Angie :)
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Well done Angie, nice job.
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Looks fantastic Angie and I'm pleased to see the tea mug at the ready under the staging - for visiting forum members....
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Angie, your greenhouse and tunnel look fantastic!
Not to mention soooooo much tidier than mine ;D
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This is a really useful thread. I'm considering replacing the original slatted wooden staging in our greenhouse because I'm short on space and I can't put a great number of pots on this staging due to weight. My main decision is whether to use plunges or not. Many of my plants are grown in plastic pots which are quite happy standing on a gravel tray, but I have increasingly come to the view that some of my bulbs really don't like to be in very damp compost at any time, and plunged clay pots would suit them better. Maybe half & half (plunge and normal staging) is the way to go.
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That's an incredibly neat greenhouse Angie, puts mine to shame ::). Oh to have the space....
It looks to be a better idea using aluminium plunges on a timber frame than my construction of exterior grade plywood plunges sitting on top of brick pillars. They are incredibly heavy to manoeuvre into the greenhouse fully assembled and my brickwork for the pillars leaves a lot to be desired. If I ever have to start again due to moving house, I'll know what to do now!
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Angie, the frog is perfectly visible in the Echeveria pot.
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This is a really useful thread. I'm considering replacing the original slatted wooden staging in our greenhouse because I'm short on space and I can't put a great number of pots on this staging due to weight. My main decision is whether to use plunges or not. Many of my plants are grown in plastic pots which are quite happy standing on a gravel tray, but I have increasingly come to the view that some of my bulbs really don't like to be in very damp compost at any time, and plunged clay pots would suit them better. Maybe half & half (plunge and normal staging) is the way to go.
Like you Darren most of my plants are in square plastic pots (apart from my Cyclamen for which I've used clays this year) and if they are happy you have the added advantage of being able to cram so much more in there. You would probably have to face the problem of what not to grow!
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Magic Angie and I couldn't see any pools of blood from skinned knuckles either :) :)
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Magic Angie and I couldn't see any pools of blood from skinned knuckles either :) :)
No Martin I cleaned it all up, mine were all right as I was just supervising and drinking coffee out of my SRGC mug, it's the most used item in my greenhouse.
Darren and Hans did you notice all my lovey plants. ;D ;D
I was at Ian Young's today and he has square pots in his plunges, you certainly get more in. I haven't got to many plants YET to worry about space.
Thanks again everyone for the help, advice and plants, I am so lucky to have met so many great people on this forum. I would hate to be without my computer now. Hope to meet you all at Alpines 2011
Angie :)
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I did notice some Massonia, yes Angie!
David, most of my Cyclamen are in clays too - plunged in a fishbox under the bench. I do have a plunge in the other half of the greenhouse (it houses Massonias etc, and central asian Anemone). I also have a plunge bed which is simply set up with a few cm of sand in the bottom and has deep plastic pots just standing in it. These are full and I'm very aware of all those germinating pots of bulb seed which are going to need a home...
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Angie,
Everytime you show us another part of your garden I feel the need to visit. You have a wonderful greenhouse and some great looking plants. I think you are too modest in some of your postings.
I see there is a mug in the greenhouse - do you keep a kettle and some tea in there also. ;)
Graham
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Your greenhouse and tunnel look wonderful, Angie. So much tidier than my overcrowded greenhouse. I've been thinking about buying plunge benches for my greenhouse but the thought of moving everything out and back in again puts me off.
I will be over to see your garden and greenhouse as soon as I am able to drive again even though it will be the middle of winter.
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Many congratulations Angie : a wonderful achievement !
Happy growing !!! 8)
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I see there is a mug in the greenhouse - do you keep a kettle and some tea in there also. ;)
Graham
Don't tell everyone there is also chocolate biscuits as well.
Roma you and others have said how tidy my greenhouse is the reason is I haven't reached the stage that all you folks have. I have to hurry and find more plants that I get to the stage of overcrowding ::) ;D this I can't wait for.
Hope to see you soon Roma.
Angie :)
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What a wonderful new polytunnel Angie and everything in perfect order (don't worry, you've plenty of time before next April when the Aussies come, to have it looking messy ;D)
Here, a tunnel or polytunnel means that covered place where all the rubbish gets dumpsed and the gum leaves accumulate to make a thick carpet of non-composting material which shelters slaters and beetles.
Lucky you, to have a resident frog. :D
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Lesley it soon will be untidy when I start potting up all my spare garden plants.
Lesley I wish you were coming over next April I was saying yesterday to Dave that I would love to meet you, you sound such a lovely lady.
I will try and keep the greenhouse tidy ::) ;D
Angie :)
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Lesley I wish you were coming over next April I was saying yesterday to Dave that I would love to meet you, you sound such a lovely lady.
Angie :)
Angela, Ian has met Lesley and they got on well.... I have yet to meet her in person but I can tell you she has been very kind to me and helpful - arranging surprises for my sister's birthday and so on.... a good friend and I would love to be able to meet her properly and give her a thank you cuddle- even in her untidy polytunnel!!
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See I was right, Maggi you have said it, a really kind person. Lesley Maggi and I would love to meet you someday soon.
Maggi maybe we need to go over a tidy up these polytunnels ::) ;D
Angie :)
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Lesley I wish you were coming over next April I was saying yesterday to Dave that I would love to meet you, you sound such a lovely lady.
I bet that raised a snigger ot two! ;D
But thanks Angie and Maggi, for generous comments and kind thoughts. One day maybe.....