Scottish Rock Garden Club Forum
Cultivation => Composts => Topic started by: Paul Cumbleton on August 27, 2009, 01:28:52 PM
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With the environment in mind, the RHS is striving to reduce its usage of peat and it is likely we will aim to go further and stop using peat altogether. As even John Innes compost contains peat, this means we would not be able to use what is at the moment one of the key ingredients of our composts for alpines and bulbs. I would like to know if there is any experience out there of growing alpines and bulbs in composts that could be said to be made entirely of renewable ingredients? Is it possible? How are such composts managed? How do they perform long term? Ideally we would like to end up using composts or ingredients that are available to buy in a bag from garden centres, so that we use something that everyone can obtain (so things like leafmould that not everyone has access to would not be our first choice). Can anyone suggest candidates we should try?
If anyone has actual experience or suggestions to try or any other comments about this, I think this would be a very worthwhile area to discuss (although the phrase “can of worms” also comes to mind….!). Over to you all…
Paul
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I suppose we are using what is pretty well a "renewable" compost, Paul. We use loam, sand , gravel and composted shreddings. We have access to leafmould and do utilise that where needed, but the other ingredients can make a perfectly good compost which maintains a good structure over several years; that is, it does not break down to become either too sticky or dusty, but remains a good "texture", if you know what I mean!
The current insistence of many to move completely away from the use of peat does rather beg the question, to me, of what happens when it is decided that sand or gravel or even loam, is not sustainable for large-scale use for commercial composts?
After all, sand and gravel are not in endless supply and their extraction from the earth can cause problems too, can it not ? ::)
The whole area is rather fraught with inconsistency of logic, I reckon! :-X
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Paul,
I remain convinced that we can grow our plants in ANYTHING so long as nutritional needs and physical support needs are met. I've always intended to experiment with broken clay pots, crumbled glass and the like to prove that it can be done. A light, regular feeding ought to account for macro- and micro nutritional needs.
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Would there be a use for bark, shredded and composted bark. I used shredded bark for a footpath in the garden a few years ago and found that after a few seasons it had broken down to a very fine material similar to leafmould. Presently, bark is a by-product of the timber industry and, by and large, is a waste product.
I could not comment on its use with alpine plants though I imagine the addition of grit, sand or gravel, would make it suitable. I have found it perfectly fine for some woodland plants.
Paddy
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We discussed the peat topic some years ago.
There are very large resources in Scandinavia and even larger in the baltic states and gigantic resources in Russia.
I think I remember that the conmbined peat bog area in Scandinavia is larger than Scotland and the thickness of the layer is growing all the time.
No habitat, plant or animal is in any way endangered by the mining of the peat in Scandinavia or east of us since only minute parts of the total peat bog area are suitable for commercial mining.
I cannot understand why you cannot use peat from say Estonia or Lativa. They do need the influx of currency and today they use the stuff as fuel in power stations.
Because of the cheapnes of the currency and wages in those parts of the world it would probably be much cheaper than that mined in the UK and that includes transport.
Cheers
Göte
>:(
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As a 'no peat' person I use a basic compost of equal parts loam, grit and leaf mould. B&Q soil conditioner replaces the leaf mould when this runs out. Whilst not being one of the SRGC's 'top' growers I find it to be a satisfactory mix.
Peat? My argument is that peat itself is not the issue but the biodiversity that it supports. All the wild life (plants, insects, birds, etc) utilise the top few inches of the moss. Remove this and you lose a whole ecosystem.
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Hi Paul,
Most potting-mix producers in Australia abandonned peat a long time ago (probably around 20 years ago I think) and we still have a thriving nursery industry (barring water restrictions!!) which relies solely on "peatless/soilless" mixes.
I grow all my potted plants (albeit not too many alpines, but a large number of bulbs) in commercial mix which is mostly composted bark - to which I usually add some grit for better drainage.
cheers
fermi
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I grow all of my potted stuff in commercial potting mixes based on composted pine bark. Almost all my little treasures you see me post on these pages (some of which at least would be classified as "alpines" I think) are in a good quality commercial mix, sometimes with sand or grit added for drainage etc. The only other thing I sometimes use is Sphagnum moss, for certain plants such as some carnivorous and some orchids. No peat used here as far as I know. 8) That said, I still do have an old compressed bale of "peat moss" from years ago I think...... dreadful stuff to re-wet if it dries out of course. :o
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Hi Paul
I grow a wide range of bulbs in hammer milled pine bark which has been composted at least 6-12 months with Urea. I add 10% quartz sand and one tonne of dolomite/25 cubic metres to this and allow another 6 weeks for ph to rise. Moisture characteristics are pretty good but a problem if allowed to dry out. The bark tends to break down after 2 seasons and becomes stale, for want of a better word. The bark is also quite hungry in that Nitrogen drawdown can can be a problem unless a fairly constant dilute fertilizer regime is kept up.
I have trialed coconut husks (coir peat) also, which acts quite similar to natural peat. This is suitable for bulbs needing higher available moisture levels.
The problem as mentioned by Maggi, is that quartz sand is a limited resource here now and is extracted from riverbeds. Expanded clay beads or similar could be an alternative.
In New Zealand, commercial growers are using pine wood shavings as a medium with success. As Carlo has said, a potting mix is merely a medium for support and moisture/nutrient retention. Possibilities are great.
Goodluck. Tim
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We do not need quartz sand. Any sand that is not decomposited carbonate stone will do. Sand of suitable grain size is a byproduct in many places where gravel is mined for roadbuilding and other purposes. It is a question of looking in the right places. The amounts consumed by us is very small compared wioth the amounts handeled by these companies so we are not good customers. Sometimes the problem can be solved by asking to be allowed to collect some surplus from the operatins and contributing to the coffe cash box.
Cheers
Göte.
PS
If we dig peat we do destroy a habitat but east of the North Sea the destruction is less than a promille of the surface. Further. If we dig all the peat from a bog we restore the original lake and what is wrong with a lake as habitat?
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Bark can (according to some) support/promote infection with Honey Fungus (Armillaria).
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Thanks everyone for the responses so far. I agree with Maggi that this whole area is fraught with inconsistent logic. I will be meeting next week with our head of science so I can discuss what the RHS view is on the wider environmental issues, for as Maggi says, there are many ingredients such as loam, grit etc that we use that could be said to be unsustainable too. I would not want to embark down a road of learning how to manage a new type of compost only to find that in a few years time I have to give this up too. But I didn't really want to discuss the peat issue as such here, I more wanted to see what other things people have experience with.
Carlo & others commented on a compost providing mainly support and nutrition so that all kinds of things could be usable. I feel things are a bit more complex than that - a compost has to provide the right balance of aeration, moisture content, pH, etc that is suitable for the plants we grow. Finding a suitable mix could be difficult. Particularly so as I want to use ingredients available to anyone (in the UK at least). All our current composts use ingredients that anyone can go and buy at a garden centre. I feel this is important - if we were to use ingredients or professional mixes not available to amateurs, then it would be difficult to pass on our knowledge to the gardening public as it would be based on using things they cannot obtain. Several of you relate experience with composted bark and this does seem to offer possibilities - we have already tried this on a small scale trial here but we need to experiment further.
I will also be meeting with a rep from a company that produce peat-free mixes to see just what they offer and whether any would be worth trying - if they contain ingredients that anyone could copy.
Keep the experiences coming. I will report back what we eventually decide to do.
Thanks everyone
Paul
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..... as I want to use ingredients available to anyone (in the UK at least). All our current composts use ingredients that anyone can go and buy at a garden centre. I feel this is important - if we were to use ingredients or professional mixes not available to amateurs, then it would be difficult to pass on our knowledge to the gardening public as it would be based on using things they cannot obtain.
I applaud this desire, Paul. If the RHS is to be truly helpful to and supportive of, amateur gardeners, then this aspect is crucial.
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Paul, have you ever tested Green Ore Compost to see how much peat there is in it, I would be interested in the result? It doesn't look or feel a peaty compost to me.
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Hi David,
The Green Ore brand of John Innes conforms to the original "true" formula for John Innes - which means it has 7 parts of loam, 3 parts of peat and 2 parts of grit (plus the fertiliser). This means it contains 25% peat. Of course this means that 75% of the mix is not peat, which is why it doesn't look or feel particularly peaty.
Cheers
Paul
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Thanks for that Paul, it is really good stuff. That is why I now do a round trip of about 200 miles just to buy Green Ore compost. Pity if you had to give it up!
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Im surprised nobody mentioned coco fibre (coco nut hasks) which acts like peat and is a recycled product and theres plenty of coconuts on this side of the equator!
As an additiion to our potting mix our nursery uses it for growing all sorts of plants and we are a cool climate garden with alpines included. Our mixes contain quarts sands, composted fine wood chips, coc fibre, perlite if needed, zeolite and clinker. The Aussie nursery trade uses similar mixes.
Most of these products are recycled products or man made ones except for the quarts sand which is being mined. We use to use river sand but stoped.
In the EU you can get your hands on Seramis which is a fine man made product with cation exchange, absorbs water and nutrients.
hope this helps
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Environment questions are tricky. In some ways I am reminded of the old proverb: However you turn, your tail is on your backside.
Coconut fibre, leaf mould, bark and peat are renewable materials in so far that they grow naturally and would not have any other uses. In a temperate climate, leaf mould decomposes and releases the nutrients it contains into the soil where the trees grow. The same goes for bark. If we use the bark for horticultural use we (to a small extent) remove nutrients and soil conditioners from the forest. However, most bark in the market is a by-product in saw mills and would not be shipped back to the forest anyway.
Peat is different in that it does not decompose in the place where it forms. It is a growing resource. In the countries east of the North Sea it has filled a very large number of lakes and this is an ongoing process. People who like lakes, fishes water lilies and aquatic fauna and flora generally have some difficulty in understanding why the very barren peat bog should to be preferred.
Peat bogs cover approximately 2% of the total land surface of this planet and the total reserves today is assumed to be about 3 trillion cubic meters. In peat rich countries it is mined and used for fuel. Horticultural use makes an exceedingly small dent in the peat resources The main point is, however that the peat resources are growing faster than they are consumed and the amount of peat in the Scandinavian and Baltic states is steadily growing.
Searamis is clay that is mined in Westerwald in Germany, foamed and fired. This means that a non-renewable recourse i.e. the clay is burnt in a high temperature process presumably using another non-renewable resource i.e. oil or coal releasing CO2 to the air. However, the production of Seramis is probably insignificant compared with the large amounts that go to clay brick and earthen ware.
Quartz sand is an important raw material in i.a. glass making and from the horticultural point of view sands containing feldspars and other more complicated minerals are equal (and vastly more abundant) as long as they are not carbonate minerals (lime stone, dolomite etc), which change the pH of the soil. It can be argued that feldspars are better since they release potassium but the amounts are negligible in practical use. In most parts of the world sand is very abundant and sand of horticultural grades, is often a by-product in the mining of gravel. Sand is indestructible and it doubtful that there is something wrong in moving some of it from a deposit in a sparsely inhabited area to a garden in a town. This provided that the mining is not too destructive in itself. The sand in a pot of John Innes has a longer life expectancy than the town in which the pot stands.
The important issue is not whether we use a specific material or not. The important question is: Where and how did it originate? To use horticultural peat from a Baltic deposit is hardly detrimental to the environment. To mine peat in the only peat bog in an area where there is no formation of new peat and where bogs are rare is of course not environment friendly. To destroy a river sand bed is not to be commended. To use a by product from a gravel operation that otherwise would be dumped should not pose any problems.
Cheers
Göte
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Yes Gote like you say depending on the source and if its a renewable one. Peat bogs in Australia isnt as we dont have much at all. Back in the 80s when a peat bog was being dug up it collapsed and washed away and with it a rare vegetation type that relied on the peat supporting it. It was an ecological disaster and one not to be repeated. So when the resource wasnt there we tend to improvise and look elsewhere. Dont really see peat on the shelves in markets, i dont think its imported anymore.
Interesting what you say about Seramis.I see why its expensive.
cheers
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A local solution: our local corporation collects all compostable material from homes in the town and sells the resulting compost.(3 euro per 45 litre baf) It is good quality, slightly alkaline and perfectly suitable for the vegetable patch, at least. In the last week I have collected about 40 bags from the composting facility - it is being given free for the month of September. An information leaflet from the facility says it is also suitable as a mulch in the garden and as a potting medium.
Paddy
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A local solution: our local corporation collects all compostable material from homes in the town and sells the resulting compost.
Some councils give away such compost - I wonder how free of pests and diseases it is?
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David,
I would be confident of the safety of the compost given the temperatures reached during decomposition - huge volumes of material lead to very high temperatures.
Paddy
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A local solution: our local corporation collects all compostable material from homes in the town and sells the resulting compost.
Some councils give away such compost - I wonder how free of pests and diseases it is?
We have it here in Örebro too and it is quite good. Only problem is alkalinity since I grow several lime haters.
I have never found a single weed in it. Nor any pests nor diseases but the latter may of course be there without my noticing it.
It is quite useful to augment the soil I use for Numphaeas.
Cheers
Göte
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It seems we have already addressed most of the typical compost ingredients. I have spent the last 10 years exploring various elements for potting and bed mixtures, as, living in a city in Germany, I cannot simply go and pick-up a bag of manure or John Innes! Sounds silly, but there are no local garden centres that carry truly 'raw' ingredients. One has to get inventive and try other items out or take a day in the country and rob some stalls.
Finding a basic, such as loam, is close to impossible, unless one wishes to have a truckload sent in (and then it is full of weeds and hardly deserves the name loam). I have taken to mixing cocos (coir) with lava gravel (used for de-icing) and play-box sand to get a basic mix. Composted bark is added to create a more woodland or acid mix. When I need gravel, I buy basalt split.
One thing to keep in mind with bark; it will take-up most of the nitrogen in fertilizers, until it starts to really breakdown itself. This is due to the bacteria doing the breakdown. After the process is completed, the bark will start to release the nitrogen back into the soil. This can be a problem in a pot!
I have stopped using peat for a number of reasons. Firstly, it hold much too much water for a potting mixture in my climate. People buy it as a mix for their window boxes and the poor plants simply suffocate for lack of air at the roots. In general, coir has proven a better choice for me. Secondly, it drops the pH of the soil. Then there is the ecological issue, which has been discussed, but, frankly, this is certainly over-played!
I have recently started using a commercial coir mix, which is touted as saving our peat resources, of course, but find that its relatively open structure is just what many of my plants like. Open structure is a real issue for me. I use gravels and sands to lighten mixes, but they do add considerable weight. Perlite is rarely avaialable, as the market product in Germany is fire retardant and designed as insulation, not for the garden. Occaisionally, I find a bag of the basic stuff and buy what I can transport. The last time I saw vermiculite was in England.
In the end, it is very frustrating to find garden safe products, if you are not a commercial gardener, as the main uses of many items is not gardening. On the continent, I often get the feeling that gardening has become politically incorrect! Mind you, that has never stopped a true gardener. And there are still quite a few over here, thank you.
In the end, I am very happy with coir as a peat substitute and simply gather as many leaves from the streets in Autumn that I can. If only a cow would wander by....or, maybe a horse. ;D ;D
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free vermiculite is obtainable from your local Honda dealer if you go and ask. it comes as a packing agent around new batteries . my local garage keeps it for me and i use it in my compost mixtures .
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Hi, Samthe Bam, welcome to posting!
Now that is an extraordinary tip about the battery packing........ who'd have guessed that! 8)
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i know this is not a compost , but this is another reusable item from the motor industry. many bumpers come wrapped in bubble wrap (especially Honda's) with white diffused foam on the inside which is excellent for greenhouse shading , these come in large sheets and are best obtained from a auto bodyshop .
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i come to the issue of potting media from the direction of cactus and succulent growing, where there is a HUGE amount of discussion of the issue..
as carlo mentioned, for most plants, the substrate is only one issue, and there are highly successful growers using mixes that others would swear are a death knell..
for those sorts of plants (cacti and succulents) i avoid peat like the plague--unless you are constantly repotting, like a commercial nursery, many of whom do use it for cacti, it breaks down into some concrete like substance--it took me weeks to wash it completely off the roots of my (indoor) collection when i switched to loam based media (when i was still living in toronto);
this wasnt easy to get in downtown toronto, as most commercial mixes in ontario have peat and are based on composted bark, which is also supposed to be not that great for c+s, due microbial and fungal activity which plants from arid places are not adapted for, but i was able to go to a retail gravel supplier and buy self fill bags of
rather clayey loam... this was mixed with various kinds of grits and gravels, coir and crushed brick-something european growers of c+s are fond of..
perlite and vermiculite are readily available here, but i reject them on aesthetic grounds--esp perlite which inevitably floats its hideous self to the surface; nothing worse to me than seeing a beautiful plant surrounded by those artificial white beads;
now, living in the country, my approach is totally different, since i can harvest several types of soils/amendments (clayey loam, black wooded soil, peaty stuff, decomposed animal manure, composted leaves, conifer duff-if i had a reason to!) from my own acreage, but most of these base items fall in that not useful to recommend to the general public;
i still need to buy grit (usually poultry grit, and zeolite, like a sharp artificial sand) and coir to open up especially the clayey stuff in pots; coir is very available here, now..
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Hi Cohen, I'm in more or less the same position and start my mix with John Innes. I grow mostly Lithops, highly xeric cacti, and some other succulents, but also some alpines. I would imagine that peat isn't the first choice of most alpine growers, but then a surprising number of C&S growers still use it so I might be wrong. Outside the UK (and Oz and NZ?), standardised loams like John Innes are difficult to find and ingredients like coir are much more popular. I know JI typically is about a quarter peat but I'd happily do without that quarter. I've successfully grown in loam from my garden, plus aggregates for drainage, but it is highly alkaline and a little inconsistent for use with small potted plants.
I feel it is a shame that newcomers to our areas of growing will be directed to possibly the worst starting point for stable free-draining soil, which is a bag of peat with a little perlite if they're lucky. I struggled for years before I realised that the stuff in the garden centre that says Cactus Soil is nothing of the sort ::) Mixes based on high proportions of bark or coir would be a far better introduction and there would be no need for beginners to learn how to work around the limitations of peat.
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Hi Cohen, I'm in more or less the same position and start my mix with John Innes. I grow mostly Lithops, highly xeric cacti, and some other succulents, but also some alpines. I would imagine that peat isn't the first choice of most alpine growers, but then a surprising number of C&S growers still use it so I might be wrong. Outside the UK (and Oz and NZ?), standardised loams like John Innes are difficult to find and ingredients like coir are much more popular. I know JI typically is about a quarter peat but I'd happily do without that quarter. I've successfully grown in loam from my garden, plus aggregates for drainage, but it is highly alkaline and a little inconsistent for use with small potted plants.
I feel it is a shame that newcomers to our areas of growing will be directed to possibly the worst starting point for stable free-draining soil, which is a bag of peat with a little perlite if they're lucky. I struggled for years before I realised that the stuff in the garden centre that says Cactus Soil is nothing of the sort ::) Mixes based on high proportions of bark or coir would be a far better introduction and there would be no need for beginners to learn how to work around the limitations of peat.
ian, i'm ashamed to say i've never done any kind of testing on the native soil here, so while i assume its relatively alkaline, i couldnt say for sure--i'd say more so than in the wet areas here, or in the heavily spruce parts of the woods, and presumably less alkaline than in drier less wooded parts of canada's west..but those are rather vague assumptions...i really should read about it more (i've started that a bit) and do some soil testing--never done it, but i suppose materials for that should be easy enough to get?
i've had excellent results with those plants i have started or repotted since i got here--including seeds i have started-using the native loam (couldnt really say 'garden soil' as its not taken from any pre-cultivated areas, just spots i am either digging new beds, or digging for some other reasons; it sometimes scares me as very clayey, but plants dont seem to mind, at even 50% with coir and grit/zeolite;
note, for some seeds of more woodland things, i replaced the clayey loam with soil from a pile of topsoil left from an old sewer excavation--more at the edge of a wet area, this is blacker soil, still loamy, but clearly much higher organic content..