After growing maples for the past 7 years, many of them in containers, I have been looking for methods that will improve the health and vigor of my plants. I lose a few maples every year, and some of my trees seem stunted, putting on very little growth, or suffering more dieback than seasonal growth. I am sure that there are several improvements I could make to my care regimen, including more routine watering. In a yard with sunny areas, part shade, and dense shade, I find that my plants dry out at radically different rates, and so I either have to check each of my 175+ pots daily, or water everything every 2-3 days and hope that I dont drown any of them (this is the method I chose.) If we get a hot spell, even 2-3 days can be too long for some of my plants; I had a few lose all their leaves after I went camping in August for the weekend. I have been reading alot, trying to learn what the ideal soil would be for containerized maples. There isn't much info out there. Most people either use regular potting soil from the hardware store, or they make a peat based mix adding random items to help improve drainage. I have also seen some nurseries grow in a bark-perlite mix. I found there weeew hundreds of threads on the gardenweb forum discussing "Al's Gritty mix" which is described below. It seems that the gardenweb Container Gardening forum is the only place where this issue is being discussed. I am surprised that with all the experienced nurseryfolk and maple enthusiasts here in the UBC forum, this topic has not been thoroughly discussed. I hope that this thread will help expand our understanding of the needs of Japanese maples and what soil may best provide the ideal condtions to satisfy the plant and the grower. I am about to try out this "gritty mix" for 15-20 of my maples. It consists of equal parts of pine bark, gravel/chicken grit, and turface (expanded clay) that have been screened to remove fines and particles over 3/8" This mix is supposed to have excellent drainage while holding a good amount of usable water for the plant. One of the benefits of his mix is that only the pine bark (1/3 of the total soil volume) will ever break down, and this will take several years before there is any loss of fine pore spaces. Most soil mixes with peat, compost, and other organic materials will break down within a single growing season, reducing drainage and increasing the likelihood of saturated soils. The turface holds alot of water, releasing it slowly, and the gravel helps ensure that there are plenty of large pore spaces that will hold oxygen. Because this mix lacks any substantial amount of nutrients, I'll be using a water soluble fertilizer every 3-4 waterings. The materials pose a challenge for many people to find, but things were fairly easy for me. I sourced pre-screened fir bark that is used for Orchid soil from a local company for $50 a yard. The gravel is available prescreened to remove fines and chunks over 1/2" from the landscape supply yard for $15 a yard, and turface (thich can be the hardest component to find)is sold locally by John Deere landscape supply. Turface is commonly used on baseball fields to prevent mud in the infield, and is available in 50lb bags for $8-10. Diatomaceous earth is a good substitute if Turface can't be found. Here is a link to a very, very long thread discussing soils and water movement http://forums2.gardenweb.com/forums/load/contain/msg0622171013552.html Here is a link to many links discussing the gritty mix http://www.google.com/search?hl=en&...&q=+site:forums2.gardenweb.com+als+gritty+mix Is anyone else growing in a "non-conventional" growing medium? Does anyone find that the standard "potting soil" mixes sold in garden centers and in landscape supply centers to be inadequate for the needs of their maples? It seems like the gritty mix may be a solution to a problem that few people complain about. Are we ignoring the reality which may be that our maples are suffering in silence, and not living up to their potential? Or is this just the new fad ? Does anyone use water soluble fertilizers regularly on their maples? Which brand do you use?
I'm a JM novice so I can't speak to their culture specifically. However, I've grown a great number of containerized trees/plants and have been using the gritty mix for a few years. It is a vast improvement over peat-based mixes and I'm sure it would be excellent for JMs - or anything else for that matter. The gravel/grit plus Turface gives it substantial weight, too, which is a real plus on blustery days. The only kind of diatomaceous earth that I've used is in powder form to combat slugs, but even in a larger screen size I don't know that it would provide the same qualities of the Turface. Turface really is a unique product. I've read where others use Napa oil-dry or even some of the generic kitty litter products which are exclusively calcined clay (with no added baking soda). Even though Turface is granular, it's important to keep in mind that it's very water retentive - it is actually taking the place of the peat in the mix. In terms of soluble ferts, I've been using Dyna-Gro Grow (7-9-5) which includes micronutrients. I believe Al (of gritty mix fame) uses Dyna-Gro Foliage Pro (9-3-6) exclusively, but I've been happy with Grow and haven't tried FP. In my limited research on JMs, I've read that most folks recommend little to no supplemental fertilizing. Having grown many ornamentals over twenty years, in several different settings, I think this is probably a vast generalization from those who are blessed with reasonably good growing conditions. All plants require appropriate NPK plus secondary and micronutrients to perform at their best. If these are not present in the soil or supplied through fertilizing, the plant may live, but it will not thrive. This is doubly true for container growing where nutrients are being leached continuously. I fertilize through my drip system using an injector. If the instructions call for 1 tsp./gallon, I generally set it to inject at a rate of about 1/8 tsp. per gallon with every watering. This way the plants are getting a very low but continuous supply of nutrients. As long as the particulate size is close, I wouldn't worry too much about screening. However, if the gravel is only screened to 1/2" that might be a bit chunky for your purposes. I live close to the beach and use course beach sand that is probably in the 1/8" range. I purchased my first JMs this fall and will be potting them up in the Spring using the gritty mix. I look forward to experimenting and will be eager to hear how it works out for you.
Thanks for the reply. I'm glad to see that someone else has used the gritty mix with success. I bought a bag of the diatomaceous earth that is commonly sold to soak up oil spills, and it looks like it would work well. Turface does seem alot more durable (more like a rock than a sponge) and since I have a good source for theTurface, I will mostly use Turface. I do want to try a few pots full of alternate mixes to see how they do in comparison to the standard gritty mix. My biggest concern is that the combo of Turface and rocks making up 2/3 of the volume of the mix will make large pots very heavy. I'll be trying pumice and diatomaceous earth to see if I can reduce the weight of the pots without sacrificing drainage. I've read conflicting info about the use of sand in a mix. Even sharp sand and other gritty sands are said to reduce drainage over time. It sounds like you have not seen a problem using sand, so that is good to know. I read that Al uses the Foliage pro, and I've heard that the Dyna-Gro line of nutrients is good. I see that there are alot of the hydroponics nutrient mixes, and wonder if the would all work well. Alot of maple growers are sensitive to fertilizers because of the tendency for nurseries to feed too much nitrogen fertilizer to "push" young trees to grow quicker so they can sell for more money. These trees end up growing lanky and tall, looking completely different than the form developed by a tree grown without excess nitrogen "push." This growth is also more succeptible to diseases and pseudonomas. Nitrogen boosts also reduce the spring and fall color displays that maples are known for. I'd love to hear about what soil mixes others are using with success. Thanks!
Good thread Sasquatch. In my climate, with very dry and hot summers I want a mix that retains water so I do not have to water the pots several times a day ;-)) I use pine bark, vermiculite and oak leaf compost. The compost, in addition to retaining water, also feeds the maples which are not fertilized (I am not in a hurry to see the maples growing fast). Also, against all standard advice, I place a saucer under each pot so that any water that drains is retained. Of course, these saucers are only placed in late spring and removed in the fall as soon as the rain returns. Gomero
I like to add soil/loam to my potting mix for Japanese maples. I know this is completely contrary to the theory behind the gritty mix and I have read Al's threads on gardenweb and appreciate what he is saying (in theory). Indeed, if I wanted maximum growth from my containerised trees I would use one of his mixes and fertigate daily. That is not what I want so I use my own mix. In making my potting mix, in addition to the loam, I use bark, composted bark products, green waste products, perlite, Turface type products (cat litter here), grit and gravel. Also I add home made compost and even peat based products in small quantities. I don't use specific ratios, I just add components until I like the consistency of the mix. The mix ends up containing a wide variety of particle sizes up to larger than an inch for some of the bark chips I use. I would describe it as free draining and moisture retentive. It seems to be stable over the long term and unlike mixes with a high peat content there is not a likelihood of it suddenly collapsing into an anaerobic state. In the last 12 years I have only lost 3 out of approximately 60 containerised Japanese maples I grow, and the casualties have all been relatively new trees in their first year or two with me. I have never lost a tree that I have owned for more than two years. Maybe I am lucky, maybe it is my climate or maybe it is down to using a loam based potting mix. Who knows? It is true that my container grown maples do not grow quickly, but they are hardy and tough and rarely suffer dieback. I like Gomero's mix too, except that in my cooler and wetter climate I would not use vermiculite but replace with perlite and gravel.
I've used a variant of Al's mix. 1/8 turface 1/8 Peat 1/2 pine bark 1/4 Mini Pine bark nuggets. The turface does help with keeping some moisture in there for sure. I stayed away from the chicken grit because of weight but use it on some small less than 2 gallon plants with success. But larger one's use the above mix. I let the organic stuff age for 6 months or so before use, not right out of the bag.
Has anybody had experience with using, in French, pouzzolane, a volcanic rock (https://www.google.com/search?q=pou...&oi=mode_link&ct=mode&cd=2&ved=0CBYQ_AUoAQ),?, (what in English is called pozzolana is an ash). This material is readily available over here and used mainly for mulching Mediterranean gardens. Gomero
@Gomero, Where do you source pine bark? My mix is a bit eclectic, like Mafs. I use a little peat, also sepiolite cat litter, pine bark that varies in size but is mostly a few mills (I put it through the garden grinder multiple times), some compost for citrus, some leaf compost. The result is mixed in size but drains very well and stays humid but not wet. My intent is to get hold of some perlite also, but I have yet to get a price on it from the horticultural supplies web site. I have tried pouzzolane but find it too large. -E P.S. should add I now also use mycchorizae systematically.
I like to use a variation of Peter Adam's mix from "Bonsai with Japanese Maples". A common misconception is that bonsai requires a tree in a small pot, but actually some bonsai are so big it would take several people to move it. In theory we are all growing bonsai when we put our maples in a container to grow. I think we can learn a lot from bonsai culture, since they have been successful in growing trees in containers for thousands of years. Peter Adam's book focuses on specifically growing and caring for Japanese maples. It's my favorite book next to Vertrees bible. If you are a collector who is running out of room like me, then bonsai with Japanese maples is a great way to grow your collection and I find it very satisfying. Check out page 16 on Amazon's free preview for Adams soil mix: http://www.amazon.com/s/ref=nb_sb_ss_i_0_11?url=search-alias%3Daps&field-keywords=bonsai+with+japanese+maples&sprefix=bonsai+with It’s my opinion that commercial potting mix is for growing annuals, but I am also a believer in sticking with what works for you in your climate (if commercial potting mix works for you). In my climate I have never had good luck with commercial potting mix. I have best results using composted peat (rich black color, not the powdery brown peat) and pine fines as organic matter with a mix of smooth and sharp minerals. Please see my reply to pot bound acer for the full recipe and the theory behind it.
For all containerized JM production in #1 and larger containers, we use a 75% Bark 15% Pumice 10% Peat Moss For small containers (#1-#5) the mix has 3lbs/yd Actino Iron. If we uppot in the spring, we also incorporate a slow release fertilizer, otherwise we top dress. Even in large quantities (full truckloads), a mix like this can run a grower $30-50/yd depending on their location.... -Brent Rare Tree Nursery www.raretreenursery.com
Interesting, JT. Gritty Mix Al is a bonsai practitioner, too, so I wouldn't be surprised if his ideas have been shaped by Adams's writing. The concept of smooth vs. sharp rocks and how they affect root and top growth is fascinating. I've never heard this before, but it makes sense. Thanks for posting.
Emery, I buy it in 50 l sacs in standard garden centers or hypermarchés. There is one kind called pine bark for mulching which is small size. I am surprised you find pouzzolane too large...... Gomero
Ah ha, I feel as though I've been missing something. You mean you just add the 10/25 caliper pine chips directly? I had always thought that when people here add pine bark they mean shredded. Indeed that's what I buy, but then I put it through the garden shredder -- where it mostly falls through -- multiple time to get down to more of a 5/10 size, and a lot of smaller chips too. I'll check the caliper of pouzzolane again, but I remember it being around 10. One thing I meant to mention before: presumably we evaluate the success of a potting mix based on how well plants perform in it. But of course each maple is an individual with greater or less vigor. It's interesting to see how 10 "identical" 2 year old trees, which have got to pretty much the same size, are completely different underneath when potted in the exact same mix. A couple will have only a small root mass, where several will be outgrowing the pot. My point is that it takes a lot of pots with a large sample space of trees to really evaluate how well the mix is working. -E
Re: O.T. A few quick notations. There are many variables that come into play as to what soil or potting soil mixes we may want for our trees, depending on where we want to grow them. As far as areas in which the native soils are more than adequate for growing Maples in the ground, then few areas can compete with the Fraser Valley or perhaps the Willamette Valley in Oregon. If people will ever learn to take some time to study why these areas are so well thought of for growing plants then possibly they can equate what we want for our trees grown in the ground and in containers. Much information on soil mixes has already been presented in this forum as well as the UBC Citrus forum. It does not take much effort to go back in time and read some of the older posts that may still be pertinent today with some of our growing issues. One of the best methods to better analyze what may work for us is to study the soil mixes that our successful growing nurseries are using for their soil mixes. Learn what Buchholz nursery is using compared to Iseli nursery and compare both of them to Monrovia nurseries soil mixes. We can certainly save ourselves some time and grief if we would only pay more attention to what has been successful for others that have been growing plants on a large scale for a whole lot longer than most people in the entire UBC forums have. It is silly to yield to new thinking when application of that method has not been applied on any real scale as of yet. There is a reason why I feel quite comfortable with the EM method approach not only for Maples but for a host of other plants. It all comes down to us letting elements of nature help us as opposed to us expecting great things from our plants and find a way to suppress or advance growth in our plants at a pace that restricts growth and development elsewhere in the plant. Root growth comes first for me and I am tired of stating this over and over to the point of being it ad nauseum. There is not a lot I can do other than point out short term and long term concerns from adding in additional nutrients to our soil mixes for trees that are not ready yet in their development for doing so. I have found it far better to hold off on fertilizing young Maples until they have reached juvenile age as I've seen the results of natural grown trees compared to over fertilized trees by the time these trees went into the ground and have some knowledge as to how long both will more likely live in a wide range of climates. Maf once suggested we study how the native trees have done and are doing in Japan to better equate what we may want to do for our trees when grown elsewhere. Who has bothered to study what soil mixes have done well for the Japanese, even to the point of knowing what may work for the bonsai specialists for a soil mix may not work well for the same Maple grown as a container plant in other areas of Japan. The concept may be the same or similar as to why I don't tell Ron what to use for a soil mix in Washington and why he knows better than to tell me what to use here. What may work well where he is may not do too well for plants grown here and vice versa. Each area will be a little different than the other with so many climates and microclimates, soil substrates, soil microbes, soil pathogens - beneficial and non-beneficial, water holding capacity and lack thereof that an across the board proposal of a soil mix that will work well for someone may not work too well for others. Fast drainage is not always all that important in some areas when we have water holding capacity that does not lead to an outbreak of soil fungal issues. Compacted soil is much more of a cultural issue for Maples than perhaps anything else which is one of the reasons why some nurseries have chosen to add in pumice and/or vermiculite and/or sponge rock and/or coarse sand in their soil formulations. An added note: still one of the best rooting mediums for rooted cuttings is coarse sand, sponge rock and perhaps vermiculite mixed in the cutting flats. Our mix was 50% coarse sand, 40% sponge rock and 10% vermiculite and this was our rooting mix for all cutting grown plants from Hendersonii Clematis to Azaleas to Camellias to Maples to Pines, Dogwoods and to Magnolias, all with overhead sprinkler irrigation both outdoors in a lathe house and indoors in a greenhouse. Sometime check out and read some of the great posts on Coir in the UBC Citrus forum. At one time some of that content was the the most advanced anywhere on the internet [I cannot guarantee how much of that pertinent information is still posted in that sub-forum after a few shenanigans from more than one party]. A potting mix of coarse ground coconut husks and perlite may be quite a benefit for some people in this forum, especially for container grown plants in a greenhouse. Jim
Great thread! I, for one, am always looking for new ideas for a good soil mix for my trees, maple or otherwise. As I am a bonsai enthusiast, I am very familiar with the concept - and challenge - of having a mix that is free draining yet retains water sufficiently for the plant in question. Unfortunately, this was not the best summer for my maples, or plants in general, here in the midwest as we had over 50 days of 100F or higher between May and September, and I lost several trees. Currently, I am using a mix of 1/3 pine bark, 1/3 Fox Farm Ocean Forest soil (contains perlite), and the final 1/3 is a combination of equal parts haydite (calcined clay), kanuma (like haydite, but is more acidic), and chicken grit. I have only been using this mix since late summer, but the maples I have planted in it seem to be doing well, and I will likely transplant the other maples I have into this mix come spring since it appears to be a better mix for them than what I was previously using. I have also started adding bone meal to my soil mix when potting/transplanting my trees, and am currently using the Fox Farm Japanese Maple organic fertilizer (4-8-5) in early spring, early summer, and in fall. Again, the trees seem to be happy thus far, but I'll need to give it another season or two to really determine if this is a good mix/schedule for them. The one soil amendment I keep hearing differing ideas on is sand. Some say it will make the soil too compact, while others say it helps break it up. I know it depends to some degree on the type of sand being used, but does anyone care to weigh in on this issue? Is anyone currently using sand in their mixes? If so, does it seem to be a benefit or not? I purchased some lava sand earlier this year, but have not added it to my soil mixture yet... I am also not able to find horticultural or coarse sand locally, or I would consider using that. Andrea
Hi, This topic is a real dilema because everyone has such different conditions. The best luck I have had is using a really simple 50% aged compost and 50% pine bark. I put 3-4 mycorrhizal tablets in the bottom of the container. What I am really curious about is this. I have been container gardening with maples for a number of years now and one thing I'd like to know is if anyone notices that some maples just don't seem to like containers and some do. Again, this is in my conditions so I don't want to theorize too much, but it seems like I have three kinds. One grows quickly and needs repotting every 2 years. Eventually, it gets too large (I am not good on having the nerve to prune back roots and all that yet) and I plant it in the ground. The second kind seems fine in a container, no problems; doesn't grow really fast, but looks healthy and robust. The third sulks, suffers dieback, loses its leaves too early at the end of summer and doesn't seem happy no matter if I change to a clay pot (to be sure it's not too moist) or move it to a cedar tub, or some kind of plastic container. When these are planted in the ground to die, they live. Last year I put A. palm. 'Tsuma gaki' and A. palm. 'Okushimo' because they were so ugly and scroungy I couldn't stand looking at them. They lived over the winter and while still ugly, did not lose any ground. This year I did the same with A. palm. 'Ruby Ridge and A. palm. 'Watnog' both of which I have had since 2008. I am curious to see how they will look in the spring. Anyone else find this to be true in their experience? Could it just be a soil issue?
Kaydye, I suspect you're seeing different individuals, different vigor, different rusticity. My own experience is that certain plants are just very difficult to grow, and there can be a vast difference between different individuals of the same cultivar. Why, who knows? Different rootstock, a more or less successful graft? Back on potting soil, how about a cocoa husks as an additive? Good pH (6.2), really promotes drainage, seems to not break down very quickly. I used some 4 years ago with an A. circinatum which I just repotted, the plant did very well and the husks were still not at all broken down. Very root bound, though! Has anyone used these?
Emery, Glad you mentioned this. I use it exclusively. I haven't used peat in years. The blocks are easy to store, it's nice to work with after you have hydrated it, unlike peat which can be so hard to hydrate. When I want a little heavier mix, I always add it. It can be expensive, relatively, but if I look around, I can usually find a good price. I bought two bags of grit yesterday: one was from Napa (diatomaceous earth), the other from Carquest 100% Fuller's Earth, which I looked up and it seems to be a clay product found in Georgia. I like its look better and it seems more lightweight. Has anyone used this? I need to find a product that I can use to plant a maple forest bonsai. I have been growing some seedlings for about 5 years and want to plant this next spring. I have been reading about these clays on Bonsai4Me site and can't figure out if they are being used alone, or as grit in a soil mix. It sounds like they are using them alone. On this thread it sounds like they are being used as an additive to a soil mix. I am thinking if they are used to soak up oil, they must hold water, but the drainage is there because they are granular. So if they are used exclusively, you would have perfect drainage but moisture retention that didn't break down. Does anyone use only the grit? The Fuller's Earth looks better and seems lighter, but might break down faster. Kay
Oops, Mr.Shep mentioned coir, I take it Emery is talking about the husks being something like a bark-like product like pine bark?
Yes, I'm talking about cocoa bean husks, not coco. Easy mistake to make! :) When you stir up the bag a lovely chocolate smell rises. Poisonous for dogs though. I seem to remember that Fuller's Earth clumps up over time.
I have never used it Emery, where do you buy it? I am trying to pot some dwarf conifers and I have no experience with potting mixes for them, would a good mix for maples in my area be equally effective for conifers?, or do conifers have special requirements? Gomero
We can use a nursery grade potting soil as a standalone soil mix for containerized Maples and Conifers. The issue herein is how long do we want to keep the plant with that soil mix - short term or long term. For my area we are looking at the short term, perhaps two years at a minimum and five years at a maximum before we should come in with new soil, depending on the size of the plant container or pot. As an example: if we were to take a one gallon plant and move it up to a five gallon and we want to use a standard nursery grade potting mix, then for us around here we can think in terms of leaving the soil as is for up to five years. Then when we move that five gallon plant up to a standard fifteen gallon we can use the same potting mix for another five years. Where the potting mix gets tricky is when we want to leave a plant in a large container for many years. I will not let any of our boxed plants go seven years without giving them new soil. I've had some boxed Maples for over twenty years in the same 24" box resting on top of bricks or concrete so that the bottoms of the boxes are able to air dry after a hose watering and as a result see little to no deterioration of the bottoms because of it. Makes a huge difference when we want to move the box to another location as with these cedar boxes on the ground they will almost always have their bottom boards shear off when we want to move them. If we are in an area whereby it does not matter if the roots go into the ground, then this is not a problem but when we don't want the roots to grow into the ground then there has to be a bottom for these cedar boxes, either 16", 20" the standard size 24", 30" 36", 48" and the enormous 60" box. The mix I make is hand mixed as I can mix the equivalent of 6 cubic feet of soil at a time in my large wheelbarrow. The one thing I always do for all of our potted trees is that I add in native soil as a main component to my nursery grade potting mix and the coarse ground forest humus. I want about 25% soil in my potting mixes, no matter where I am having a silt loam at home, at clay loam at the misses and an overlaying granite forest soil at our recreational cabin near Yosemite. At the nursery we used wood tiling from a local saw mill, the equivalent of a coarse grind saw dust in a ratio of three to one with riverbottom silt as our only potting soil mix from the time the plants went into a one gallon all through the time they got up to a 48" box. We used a cement mixer to mix the soil. As a notation: the riverbottom silt did have a good accumulation of diatoms, to which we never had a Calcium deficiency in any of the plants we grew at the nursery. As a matter of fact we never fertilized a Maple until the plants were at least five gallon size and then with a low Nitrogen component, such as a 4%N, 10%P and 10%K and then only gave the tree one ounce in the Spring per plant, per two years. In other words one application for a two year period. There really is not a whole lot of concern as to using a potting soil you have found good for Maples that will also work reasonably well for the dwarf Pines. Most major nurseries use the same potting soil mix medium for both Pines and Maples. An added note: I threw out caution into the wind with the water holding capacity of Coir a while back. For me, here, even in a protected covering, I found that the Coir dried out way too fast for me. When I moved the Citrus plant in question into a five gallon container with my potting soil mix I no longer had the same drying out issues I had previous with the 90% Coir and 10% perlite formulation. I can envision using Coir as a soil additive with a nursery grade potting mix that can be of great benefit to us when we no longer have access to a coarse ground forest humus. What I like about the Coir is that it does not break down fast at all, pretty much what Emery states about the Cocoa mix he has experience with. With the ability to not break down fast we limit how much soil compaction we will see in our container grown plants. As a result we will have Maples with less leaf and twig issues because of it. Aside from disease issues within the plant our number one nemesis is compacted soil. Much of the twig damage we see in an otherwise healthy Maple is directly related to the amount of free oxygen movement we have in our soil substrate. If we have good air movement we should not have any real concern of soil fungal issues, no matter how wet or saturated our soils get. Keep us informed Emery about the Cocoa. I think you have a potential winner as a potting soil component for the long term. However, just like my feelings with Coir, I am not convinced either will work well as a standalone soil substrate for outdoor grown container plants as they will be for indoor or greenhouse grown container plants - just my opinion. The proposed need to fertilize greenhouse Citrus so often during a growing season makes me a little wary of what benefit we get from the Coir other than a soil medium that does help prevent water mold issues from causing foot rot or root rot in our indoor grown and perhaps in some instances outdoor grown containerized Citrus. I still feel Coir is best used as a soil component with our current potting soil mix. Maybe upwards of 25% Coir and a potting soil mix may work well for some people, perhaps even for me as well as long as I have no less than 25% native soil in my potting soil mix formulation. Then I can go along with Coir for my containerized plants across the board from Camellias to Maples to Pines. Jim
Good hints Jim, thank you. Emery, I checked out at our local Magasin Vert: €18 for a 50l sack!!!, slightly cheaper than gold but not much ;-)). Gomero
Hi Kay, Though I am by no means an expert, I would like to offer my recommendations for your forest bonsai. In general, the native soil in Japan is much more rocky and porous than what we are used to here, hence the reason the various haydite/calcined clay/akadama/etc are used for most bonsai, whether they be maple, conifer, etc, since that is what the Japanese had to work with when creating their bonsai. Another big thing with bonsai, as I'm sure you know, is creating the fine root systems for the trees, instead of the one or two large taproots like you would typically find in a landscape tree; the more gritty soil mixture also helps to promote this. As you are in Illinois, you don't have to deal with the heat in quite the same way as I do in Kansas, but you still have a fair amount of wind I'm guessing (?). And I'm sure you have humidity come summer. For your climate, I would probably recommend not going with a 100% akadama (ie, 'rocky clay') mix as I think it would dry out too quickly, especially in a forest planting which tends to be in a wide, low container. I would recommend maybe a 50/50 mix of the akadama with an organic component, probably pine bark or the like. For some really good soil options, and decent prices (and good advice; they always respond to my emails or you can call them), I would suggest checking out dallasbonsai.com. I have used - and really like - their Fujiyama soil mix, though for many trees, it does get expensive, hence the reason I've started with my own mix. They also have several size options for the calcined clay, akadama, kanuma, etc. I have used their Bonsai Soil Mix (a mixture of akadama, etc, no organic component) for a couple of rosemary bonsai I have as they like to be on the drier side, and it works very nicely. But, as maples need more moisture than the rosemaries, I think you'd be better off with at least a 1/3 of your mix as an organic component...
