Why, wherefore and whatever!

[Palustris]

I thought that I would begin by defining what is meant by the term 'Alpine House' , but that is not that easy.

To me it is a glasshouse made, designed, altered to suit the growing of plants which for one reason or another do not grow well outside in the conditions prevailing in a particular locality. Now that definition could also refer to a glasshouse for growing Orchids or one for plants needinf heat (in a cold climate) or coolness (in a hot climate). So one then needs to define 'alpine'. In its strictest sense it means plants growing above the tree line in the Alps. Slightly less strict, it means plants found growing above the tree line in any mountains anywhere in the world. In my definition, it means any plant which I grow which is dwarf, hardy and grows on or around rocks. Mind some of the things I grow come from river valleys and some are not that hardy.

Many of these plants will grow very happily in the garden in this part of the world and that is where they are better grown. They do far better in many ways outside than in. However, there are many which for a variety of reasons do not take kindly to my conditions.

 What we are talking about is,then,  a glasshouse in which hardy (ish)dwarf plants can be grown to avoid the local climatic conditions.

So, the main enemies of these plants are excessive wet, fungus attack and insect damage. The kind of wetness meant here is not just rain, but mist and fog and lingering dampness. Many of these plants get rained on or covered in mist in their natural habitat, but that dampness is very quickly burnt off a soon as the sun comes out. Many of them grow in very windy areas where again the wet is blown away and just as importantly the spores of most fungi do not arrive or cannot begin to grow without that dampness. Finally most insects, especially aphids do not reach the plants so they are not so much of a problem, both for their weakening effect on the plants and for the number of viruses which they carry and inject into the plant tissue when feeding.

Finally the other very important reason for this kind of glasshouse is in a word' Display'. Some of these plants are so tiny , or fragile or fleeting (flower wise) that the only way to see them in all their beauty is undercover and at eye level..

[ideasguy]

A very good and VERY informative posting, Eric.

I found the fillowing points of particular interest:

So one then needs to define 'alpine'. In its strictest sense it means plants growing above the tree line in the Alps. Slightly less strict, it means plants found growing above the tree line in any mountains anywhere in the world. In my definition, it means any plant which I grow which is dwarf, hardy and grows on or around rocks. Mind some of the things I grow come from river valleys and some are not that hardy

I'm pretty certain most gardeners are only aware of the latter definition (i.e. your own definition)
I for one hold that opinion, due to the "Alpine" tags given to plants at Garden centres.

Some of these plants are so tiny , or fragile or fleeting (flower wise) that the only way to see them in all their beauty is undercover and at eye level..

Ive attempted to grow plant in those brackets outdoors, and, since I don't have as much time as I'd like to patrol the garden and offer assistance to specials, I lost them.
Very often, I don't plant out until they are in flower, so I can remember what they looked like (usually very beautiful) and wish I'd taken more care.

May I add another reason to your list? To protect dainty little plants from slugs.
Plants which just don't stand a chance out in the garden. Ive one real beauty at present - Leucanthemum catananche
I bought it in flower, and it was absolutely gorgeous. I planted it out, and it was razed to ground level overnight!
I put down slug pellets and it recovered. Then the pellets ceased to function (buried?) and the slugs have eaten it to a stump again.
Needless to say, that delight hasn't managed to give me a flower since planting.

Thanks for initiating this topic, Laurie. Its proving to be a revelation!

[NightHawk]

Thanks Eric for getting this topic rolling with an extremely detailed and informative text. 

I'm sure that anyone interested in growing alpine plants will benefit greatly from this.

Laurie.

[Palustris]

Forgot about mollusc attack. Mind being in the Alpine House does not atop the blighters from attacking. We remove a fair number of them every night. Morisia Fred Hemingway gets regularly cropped.
More to come when my headache stops

[bossgard]

Eric, George. Kathy and Laurie, and anyone else interested.
You asked for me to check in after our outing on Mt. Rainier yesterday. We weren?t able to make the goals that we had set for ourselves, but like all things it seems like there is always good in what we might think when an experience turns sour.
We checked weather reports for the day both by television and newspaper so we set out by auto quite early in the morning. Had a few rain showers on the way, but the sky looked lighter towards our destination. Got into the Federated Forest Area and the rain increased, then Rainier National Park. Everything was fine until we started the ascent up to Paradise, the mist closed in, around the mountain and we did not have camera views except for one sun break and no road pull-overs. The road up is a narrow two-lane road, that looks like it is just stuck up their by duct tape, or chiseled out of the rock. No side rails, or very few, and straight down on the side of the road. This mist came in over the road, and it was like pea-soup fog, with very limited driving vision. Followed the white stripes, and arrived at the Lodge and Information Center locations, it was raining there so my hiking buddy and I went into the Center to use the restroom. When I came out, it was starting to snow rather heavy and started to lay, and my buddy was very discouraged. My immediate reaction is that we should get out of there, after seeing the ?professional hikers? in their proper clothing, and me in my hiking shoes, jeans, and light weight shirt and jacket, no pack, no bedding, no tent or other equipment, little food.  My buddy said, ?Let?s get out of here? and thankfully he knew of another way down that was much better than how we got up there. One of the rangers behind the desk where they file their hiking plans, said to one of the hikers, this is not a GOOD day to climb the mountain. Coupled with one death on Mount Si (North Cascades) earlier in the week who fell from a trail (he was experienced), and another hiking couple that got caught in bad weather and had to be rescued --  that is my BAD experience.
Now for the GOOD part: Eric, thanks for your definition of Alpine House and the Alpine plants. On Sunday I was misted on, snowed on, rained on, breezed on, cold(ed) on, no sunshined on, low temperatured on,  but I am not a dwarf, but I am a puny little guy. And we didn?t even get past the tree-line. I think I know how an Alpine plant feels.
Seriously, a couple of questions for you guys: Since it is definitely a crime to take any type of vegetation from a Federated Forest or National Park in US where do you get your plant specimens?  I think here you have to be a licensed grower/nursery-man/propagator to even touch them. Other question: I assume that there are a number of mountaineer-plantsmen that have dedicated at least a greater portion of their lives to the study of these plants? I can also see national governments being very interested in them as perhaps a food source (?) when the Ice Age returneth. Have any of you actually got the specimens yourself? Any information posted on the Internet to study? I haven?t checked here yet.Yes, this subject intrigues me!!
-Toby
P.S. Sorry for the length of this posting. One other thing, it was interesting trying to guess the nationality of some of the pros at the Center.

[NightHawk]

Wow, sorry to hear about that atrocious weather there Toby.    Glad you got back okay.

I think as far as the law goes in Britain, you are not allowed to pick any plants in the wild.  You are only allowed to collect seeds, and only then if you are licenced to do so.

Someone may correct me if I'm wrong. 

As regards the other Alpine plant queries you have, I don't know enough about those to answer with any authority.  Maybe when Eric (Palustris) is up to it he will be able to come in and give you some better advice. 

Laurie.

P.S. Are you going to start up the 'Garden Funnies' for us again?

[Palustris]

Sorry to hear the weather was not good.
I will answer your plant queries as part of the ongoing ' essay'. But for the moment check out the American Rock Garden Society. they have a very good seed list. Also Rocky mountain Plants (used to be called, may have changed recently) and a chap called Ron Ratsco, for both American and elsewhere plants and seeds.

[bossgard]

Eric: There is a North American Rock Garden Society http://www.nargs.org/seed/exchange.html that looks like it will be a great source for us in the US. Will await your ongoing ?essay?. Many thanks.
- Toby

[Palustris]

Structures.

The needs of the plants in a way decide the type of structure. All they really need is a roof over their heads. Since they need good light, the roof needs to be transparent. Glass is the traditional material, but polycarbonate sheeting is gaining popularity.

Since these plants often grow in very windy conditions then ventilation is the next consideration. Either it should have a lot of opening windows (or lights as they are sometimes called) or have no sides at all. This has the effect of creating a wind tunnel. Even the slightest air movement is funnelled through a sideless structure. There is a safety consideration in that wind can cause tremendous damage if it can get into a structure, but not get out.

The wind also brings in with it the water which we are trying to avoid, so the sides really need to extend to just above the height of the plants.

It cannot be stressed enough that ventilation is the be all and end all of an Alpine plant house.

There are few worries about cold so the sides can  be left permanent;y open.

The material from which the house is constructed needs to be strong enough to support the glass/polycarbonate, but not so thick that it creates shadows. It also needs to be easily cleanable. I think that aluminum is better for an alpine house than the more traditional red cedar.

Another consideration is siting. Obviously it needs to be placed in full sun. The ridge should run North/South or as close as possible. This ensures equal amounts of light on both sides of the house.

As far as I know no one sells a dedicated glass house for growing alpines. The nearest thing is an Access Frame. These are like a small glasshouse, say a metre long by two metres wide and a metre and a half tall. All the sides can be opened to allow in air. These are ideal for the smaller garden where only a few plants are intended to be grown.



Otherwise, altering an ordinary aluminum glass house is the answer. It is really rather easy. Buy some extra roof openings and do not put in the top panes of glass. To prevent the ingress of birds and cats the empty spaces can be covered in bird netting.



Final word. Daft as it seems having said all that about light, there are times when some shading is needed. There are various ways of doing this, from shade netting to polystyrene sheets. Even with open sides and extra roof vents, it can get extremely hot in there. Shade netting over the top keeps the glass cooler so the house stays cooler. Polystyrene sheeting placed a short distance above the plants keeps them cool. Another method is to use wooden slats which can be placed across the roof, a little like venetian blinds.

Next is furnishing the interior.

[NightHawk]

That's a brilliant and very detailed explanation Eric.  I'm learning a lot from this. 

Good photos to accompany your text as well.

Looking forward to hearing about the furnishings next. 

Keep up the great work.

Laurie.

[ideasguy]

Eric, I am astounded. That is a very impressive alpine display feature. Brilliant.
I'm getting more interested each time I visit this topic. It just gets better by the day. Many thanks to you, Eric.
Many thanks!

[Palustris]

Sorry, the Caption for the first photo seems to have gone. This Access frame is at the HQ of the Alpine Garden Society at Pershore College near Pershore. Wish it was mine!
The glasshouse is mine!

[Palustris]

Furnishing.

Since the intention is to have the plants at a height where they can bee seen, then some form of staging is needed. There are various types, each with its own advantages and disadvantages.

The simplest type, often supplied with the glasshouse, has metal legs and slats of wood on which to stand plant pots. This is perfectly adequate for most things. The problem for alpines is that whilst they are used to hot heads they are also used to cool feet and the unprotected sides of the pots stood on the slats can get very hot indeed. However, it is easier to move the pots around and to turn them the 45 degrees clockwise, that one is supposed to do every day.

The next type is very similar except that the top is a metal tray. The tray may be just used to stand the pots in and flooded with water. This does keep the roots cooler and solves one of the other problems of slatted staging, watering plants from above (more of that later). Capillary matting is often placed in these trays to get rid of the problem of standing water. This works best with terracotta pots rather than plastic (more of plant pot choice later). The tray also may be filled with sand, again to remove the standing water and also to help keep the plant post cool. The problem here is that the trays are often only 2.5 cms (an inch) deep. This is not really deep enough to plunge the pots in to keep them cool.

One way of overcoming this is to deepen the trays by adding metal strips so that one can get a depth of about 10 to 12 cms of sand. This extra depth of sand does place a large amount of weight on the staging supports so their strength is a consideration. It does make moving pots around harder and since the roots often grow into the sand, turning the pots is harder.

For the handier type of person then there are home made kinds of staging. These also take various forms. The simplest is a wooden table with wooden sides. Those with greater skills and more facilities can make staging like this from sheet metal.

Finally there is the strongest type. This is made by building brick piers to support reinforced concrete lintels, on which are placed pressed concrete paving slabs. The sides may be again either wooden or metal or brick.

Other gadgets.

Automatic window openers are very useful if the side glass is left in, or if extra vents are added to the sides.
Automatic watering systems are available. Having never tried them I cannot describe them.
In less windy locations then it is useful to be able to add a fan. Indeed if growing some of the really difficult things like Dionysias then a fan almost an absolute necessity, even with all the glass missing and all the vents open.

Next growing regimes.

Plant pots.

There has been a huge amount of discussion about whether alpines are best grown in clay (terracottta) or plastic pots. Each has its own fan club. Plastic retains water better and is easier to clean. Clay stays cooler and absorbs water through the sides and base. Plastic heats up very quickly, and the water can stay round the roots for a long time. Clay allows the roots to breathe through the porous sides and drains quicker. It all depends on your growing regime which you choose.

Compost.

Once upon a time if you read books on growing alpines then you would have been presented with a whole list of different mixtures for different plants. Many of these had weird and wonderful ingredients and each author swore by his/her  recipes as being the best. Decide for yourself. Alpines need fast draining compost (that is not to say that they will tolerate drought, most will not) with little food content. The general consensus is that a good standard compost is about half humus and half drainage material. The humus can be anything from peat to leaf mold via composted bark. The drainage material should vary in size from sand grains to 5 mm grit. Some plants need more humus and less drainage and some need even more drainage. It is a question of knowing your plants.

Plunge.

The best for this is clean sharp sand. Even then it will become infested with liverwort after a time. All you can do is skim off the top and replace every few years. Whether clay or plastic they pots should be buried to at least half their depth, better if you can get them up to the neck.

Next time....What I have done.

[NightHawk]

Truly wonderful stuff again Eric. 

Makes for fascinating reading.  You really know your subject.

Waiting with baited breath for the next installment.

Laurie.

[Palustris]

Building Staging. Plunge bed type

The first stage was to construct a wooden framework. I used 3 in. by 3 in. tanalised fence post for the legs and for the cross pieces. This strength was needed to support the 2 feet. by 2 feet pressed concrete slabs which form the base of the staging. Before fitting the slabs all the wood was painted with a preservative paint. To give added stability I added metal cross pieces between each pair of legs. The metal bars are in fact pieces of spare green house staging. Each set of staging has 3 pairs of legs.  All of the joints are simple butt joints with brackets to hold them together. I am no carpenter. The slabs were screwed to the framework with stainless steel screws, though their weight makes them unlikely to move.



Next I used tanalised and painted  4 ins. by 2 ins wide planks to make the sides of the plunge bed. This was fastened to the slabs with stainless steel brackets



I then covered both wood and slabs with black PVC. This was to keep moisture away from the wood and so that water would drain away more slowly.



Finally the plunge material was added. This is sharp sand.



Plants added!



Given a few years it could look like this.



or this

[NightHawk]

Another excellent presentation Eric.

For a non-carpenter you have done a great job.

Informative text backed up with great photos.

Well done!

Laurie.

[ideasguy]

Wow! That is fantastic Eric!
The construction is really substantial, and with the materials youve chosen, that show bench is certainly built to last.
When did you start your project?

I'm impressed how you took photos at various stages of construction! Its a great help to us all on this forum.

I'm amazed by the large collection of plants in the last 2 photos. One thing about alpines - you can squeeze a lot of beautiful plants into a few square feet!

[Palustris]

Sorry, never thought of time scale. I reckon it took me a week to build the greenhouse (we moved it from one part of this garden to another) and make the staging. It takes longer for the paint to dry than to do the rest of it!

[Palustris]

The Alpine House proper.

Quite a while back now a friend came to visit and told us that an acquaintance of his had a large wooden glasshouse for sale. After some discussion about whether we needed another glasshouse, we decided that it was worth a look. Sadly the building in question was in such bad condition that I decided against it. However, the idea of having another glasshouse stayed with us.
As luck would have it we went a few weeks later we called in at a large Garden Centre on the way home from one of the National Trust properties. The Centre itself is largely uninteresting, but it does have toilets. Next door though is a business selling glasshouses and conservatories. It had that magic sign outside "Sale" Of course we went in. We bought an 8 foot by 12 foot ex-display model for half price AND that included delivery!

A week later the van arrived with the glasshouse all neatly re-packaged, but with no instructions as to how to put it together. The delivery man did apologise for that. Fortunately, having put together  nearly a dozen aluminium glasshouse in my time, it was no problem. We still had the instructions from our other one of the same make.

There was no problem with siting the structure. We have a large area of concrete next to the work sheds (actually old stables!).  The sheds provide shelter from the worst of the winds which we get and the ridge could run from South East to North West. This is not perfect alignment (North to South ) but better than nothing.



I had already decided that I was going to build really substantial staging in this new house and had bought the paving slabs and building blocks to do it. However, when I came to construct the base, to my horror I discovered that not only did the concrete slope towards the sheds, as I had expected, it also slope from one side to the other. The amount of slope was considerably more than anticipated too. Instead of a simple single brick base I had to construct a platform. The top left hand corner was at concrete level, but the bottom right hand corner had to be raised by about 9 inches to make the platform level.



It delayed the erecting of the house somewhat I can tell you and increased the cost also. Still once the base was finished I could go ahead and put the aluminium jigsaw together. At this stage I did not add the glass. This was done after the staging was built.



Sadly the pictures of constructing the bases for the staging were lost by the processing company  (We did not have a digital camera in those days). I built 5 brick piers on each side of the house. Across the top of those I put two concrete lintels. The 3 feet by 2 feet paving slabs rest on top of the walls and the lintels. This is an extremely strong construction.



 Having spent more money on the structure than I had anticipated, I merely added wooden sides to the staging. One side I used as a sand plunge for pots and the other I did make into a sort of permanently planted area.



Finally the glass was added, leaving out the panes which normally go just under the eaves.

[NightHawk]

Another great set of instructions Eric.  Thanks for that.

You certainly got a good bargain on that glasshouse, saving a lot of money.  More money left over for plants. 

It's also good that you've got plenty of space to have one that size.

I'm sure that anyone wishing to have an Alpine House will benefit from the instructions you've given here.

Take another well deserved bow. 

Laurie.

[Palustris]

For about 18 months this is how it was used and very satisfactory it was too.



 However, for some reason the wooden sides rotted very quickly and having saved up some money I could do some more with it. The first thing I did was to build a set of frames alongside the alpine house. These I could use as plunge beds for the plants which used to live in the alpine house sand. The brick structure was a useful place to dispose of a lot of rubble which we had taken from various other constructions around the garden.



We go to our local group of the Alpine Garden Society once a month. There is usually a decent lecture, plant sales and experts on various subjects, willing to help. One of the lectures was on a new method of growing alpines, crevice gardens. Actually it was rather amusing, the first lecture was on modern trends in growing rock garden plants and the following month the lecture was on the horrors which people perpetrated in their attempts to grow rock garden plants. Many of the pictures were of the same constructions. You takes your pick......

We were very taken with the idea of the crevice garden. I also bought a book about the same time called Miniature Gardens by Joachim Carl. This is mainly about troughs, but there are some pictures of crevice gardens in it. Best way to describe what is meant is to show a picture of the one at the AGS HQ,



The best way to build one of these in the alpine house seemed to be to use broken paving slabs. However, the only manufacturer of these locally wanted the same price for broken ones as for whole ones, so I had to think again. Then there was an article in the AGS Bulletin about hyper tufa. The answer was obvious really I would make my own ?rocks?.

 Making the rocks.

I first made three moulds using 25 x 38 mm, roofing laths. Each mould was 75 cm long by 25 cm wide and 25mm deep. They were placed on a bed of sand and lined with thin PVC sheet. The plastic was to stop the mixture from sticking to the sand and to make it easier to remove the slab from the mould.




The mix I used was 1.5 parts of sifted coir to 1 part sharp sand and 1 part cement. (measured by volume). This is slightly stronger than the usual mix using 2 parts of coir. This was mixed dry and sufficient water added for it to be spread in the mould. This was left for a few days for the hypertufa to harden.




When each slab was hard enough to handle I removed the mould and marked where I wanted to split it into three roughly equal pieces.



The slabs were then allowed to harden for a few more days before being split. I used an old saw to do this as the material was still soft enough to cut, but not hard enough to snap.



Finally the pieces were stood on edge to finish hardening and drying. I brushed over the smooth surface left by the plastic sheet to create a more natural looking finish. In all I made 42 castings in this way to give me 126 blocks with which to make the crevice garden. This took about 6 weeks from start to finish. The blocks were stood on the glasshouse floor to cure completely.

[ideasguy]

Eric, I am so impressed with what you have shown us in this topic.
Absolutley fascinating.

Excellent presentations and descriptions. Have another Gold Star from me 

[NightHawk]

Eric, you never cease to amaze me.

Making your own rocks - who else would have thought to do that.  It surprised me anyway. 

Brilliant instructions as ever.

Here's gold star number 2 (giving you a total of 2). 

Laurie.

[Palustris]

I was lucky enough to discover some ridge tiles in the garden. These I split and positioned along the back of the staging to provide support. I also left a couple of centimetres or so of the original sand plunge on the staging as support for the blocks until the compost was added.



Construction.

Before hitting on the idea of making the moulds I had made some hypertufa rocks. One of these was used as a corner piece. When laying the blocks I used a piece of 25 mm. roofing lath as a spacer, fashioning the crevices parallel to each other. After a few false starts I decided that the best looking arrangement seemed to be at an angle across the staging.



I also used the tallest blocks at the rear and sloped the construction slightly to the front. There is no particular need for a sloping surface, but it does make looking at the plants from the path a lot easier. I tried to avoid setting all the rows of blocks at the same height, to make it more visually interesting. After a lot of moving around it eventually looked like this.



Filling the gaps.

To fill the gaps I used a mixture of two parts of a compost made from ground bark and sterilised top soil to one of Perlite and 5mm grit. This is the standard mix I use for most of my plants. I did not add any fertiliser as there is a small amount in the compost and I do not want the plants to grow too quickly because of over-feeding them.



The next job was to water the compost and to press it down into the crevices. The ideal was that it was firm but not solid, so this was a delicate operation. I also had to avoid pushing the blocks out of place. As the soil in the adjacent crevice was not firm enough to hold the blocks in position. All I needed then was patience. It is necessary to give the compost time to settle and for any weed seeds to germinate before planting. After watering a few times and when I believed that settlement was complete I added a layer of 7mm. shingle to a depth of about 5 cm.

[NightHawk]

I think at this stage it is important to point out that what Eric has explained in this topic is that the result can be achieved by almost everybody.

Some may be reading through this thread and thinking, but I don't have that much room in my garden to do that.  The key here though is to be aware that you can 'scale down' the project.

The construction principles are basically the same, but you adapt them to what space you have available.

Eric has also demonstrated that you can save money by constructing the majority of the fittings yourself, using quite ingenious methods; making your own brick slabs is one such example.

So, if anyone is thinking about filling up that area of the garden that was otherwise unused, and you are interested in having an Alpine section of course, then you can't go wrong by following Eric's examples here.

Laurie.