best potting mix for 2 year old maples?

Discussion in 'Maples' started by schusch, Oct 17, 2005.

  1. schusch

    schusch Active Member Maple Society 10 Years

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    Hello. I just received 6 young japanese maples and one korean maple (Pung Kil). They look really good and healthy. They were sent in 1 gallon containers and are 2 years old. I have a question concerning the best time to replant (now or spring?) in a bigger container since they are young, as well as a question concerning the best potting mix to use for the next few years (does it differ from the mix for older maples?). I intend to keep most of them in containers and not replant in the ground (except one or two). I hope you can find the time to give me some info. I have already planted older maples but would still appreciate your help. Thanks again.
     
  2. Layne Uyeno

    Layne Uyeno Active Member 10 Years

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    Hi,

    The best time to repot or plant is during the cooler months in fall or spring as long as it's not too cold.

    As for potting mix there really is no "best". Any good, quality potting mix that allows good drainage while providing good moisture retention will be fine.

    Personally I've been using Whitney Farms' cactus mix which is a mix of fir bark, a little peat, sand, pumice and composted steer manure. I used to mix in a bit more sand or pumice in it, but found that used straight is better. I doubt you can find that product where you are.

    Layne
     
  3. mjh1676

    mjh1676 Active Member Maple Society 10 Years

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    I use what Stagreen sells as a Nursery grade potting mix. This is very light on perlite or pumice and has no medium or even small bark, it is all fine sifted. So I some perlite and about 30% small and medium pine bark (fir if I can find it). This gives a nice texture that seems loose and not too heavy. The Nursery mix has a fair amount of peat in it that will compact over time so you should consider that a very fine mix will quickly become too dense.

    I more mild climates I know of a grower that uses all ground fir bark and pumice. That is it. Now here, where it is hotter, we need something to hold moisture in the pots. So if I was to have mix assembled, which I will do soon, I would do ground fir bark, perlite, and loam in a five part mix, 3:1:1. And go from there. If I can't get good loam, which can be a problem, AGED compost is a possibility depending on where it is from or even some peat. Often the materials available in my area are not of great quality so I have to be careful.

    The key is to have it drain fast and allow air into the rootzone. The mix should not compact over time or be too rich. Composts and manures are a gamble from a fertility and sterility standpoint and I would avoid them. The cactus mix Layne mentions is a good one. We recently used it on some indoor potted house plants. It has more sand than I would want and actually hold a lot of moisture while being fast draining. I would add more bark or organics to it, but maybe only 10%.

    What I am finding is if your mix is well aged then the plants do pretty well. I have been forced to used some unaged or fresh buy dried bark in my mixes and it seems that the breakdown of these unaged components cause a nitrogen deficit. For this I have taken to using organic liquids ferts in some waterings to kick start plants that have stagnated from the lack of nitrogen. So if one can find the aged fir bark or pine, the use of exogenous fertilizers can be minimized.

    Use the very porous mix up to the 5-7gal containers. You can begin to change the mix when the plants age and have some root mass, say 15gal size. Here you can increase the density of the mix a bit, but still not compact or soggy.

    MJH
     
  4. schusch

    schusch Active Member Maple Society 10 Years

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    thanks, Layne and MJH, for the detailed and informative info. I checked what I can get here, and will try for a ground pine bark, loam, perlite and sand mix. I use a loam, sand and I guess you could call it 'clay pellet' mix for my older maples that has worked fine.
    Do you use the ground fir or pine bark in order to encourage the root development of the younger plants? and increasingly more loam for older plants so their roots can get better stability?

    as regards the pot size: what if I changed to a 15 gallon pot immediately, instead of a 5 or 7 gallon size: would there be detrimental effects?

    Thanks again.
    Schusch
     
  5. Dale B.

    Dale B. Active Member Maple Society 10 Years

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    Hi Schusch,

    I would use pine bark mulch. Don't use fine ground bark as the airspaces between the grains will be too small and the mixture with decompose more rapidly. Sand in the mixture adds nothing but weight and fills the air spaces between the bark. Only use sand if the pot is subject to being blown over by the wind before it can send a few roots into the ground. Use only pine bark and a little dolmitic limestone. Add fertilizer next spring.

    I would discourage using the larger containers. The potting mixture will decompose over time and all of the air spaces will fill as the decomposing mixture settles. Shifting the sizes up every year will give you an opportunity to replace the old mix or at least add new mix around the old. Three or four year old potting mix can become very dense and not drain very well.

    I would suggest waiting until late winter or early spring to repot. Japanese maples tend to start new root growth when repotted. This time of year it is important that the tree become hardened off before cold weather, especially if it is in a pot. The roots are much more exposed to freeze damage of the roots than if they were planted in the ground.

    Dale
     
  6. mjh1676

    mjh1676 Active Member Maple Society 10 Years

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    I agree with Dale about the pot size. It actually is about relativity of the root to pot ratio---when we talk about 1gal and 2gal plants going up to 5gal or 7gal is a big jump. Try to put a 5gal or 7gal in 10gal and you don't get the same gain. If I have a good growing plant with good roots, then I can go from 5gal squat or 7gal to 15gal as I have done this year.

    Now when we go over 15gal, that seems for of a preference as we are talking big and expenisve containers. The larger the container the more permanent the structure. I expect to leave my plants in the 15gal as long as twice the time in the lesser sizes.

    The bark and pumice mix on young plants does encourage root growth by helping oxygen reach the roots and improving drainage. The explanation you provide for a different mix in larger containers is adequate. Additionaly, the more dense root mass of the larger plant can handle the heavier mix a bit better while anchoring the plant and resisting quick decay of the medium that can happen with the bark mixes.

    By ground fir bark previously, I meant small and medium mulch quality peices.

    MJH
     
  7. schusch

    schusch Active Member Maple Society 10 Years

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    Thanks, Dale and MJH for the clarification: this helps a lot. I see the benefits and necessity for only slightly larger pots until the plant is older. Should I use the dark plastic containers used in professional nurseries? i will not use any sand.

    A question about the mulch pieces: I have easy access to either 0 - 1/3, or 1/3 to 2/3 inch size pine bark mulch (and up). Should I not use the smaller size at all, or should I mix these two sizes, or go even bigger?

    Dale - as regards not using any loam. Wouldn't an addition of loam - like MJh recommends: equal size of loam and perlite, 3 times as much pine bark - help in the summer when there is need for more moisture, or during a drought period? (Of course, it's possible to water more often) Is the perlite enough of a safety net? The plants arrived in what looks like a light loam mix - they look healthy. Does changing the medium (in this case to an all bark and perlite mix) affect them adversely?

    Thanks again for taking the time to respond in detail: I learned a lot.
    Schusch
     
  8. Andre

    Andre Active Member Maple Society 10 Years

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    I use the following potting mix :
    1/4 pouzzolane (volcanic stone)
    1/4 pumice
    1/4 loam
    1/4 composted pine bark

    I insist on composted because if it's not composted it will compost in the soil and produce heat that will burn the new roots.

    Composted pine bark can also be a good source of mycorhize.

    A very important thing is granulometry. I think the best granulometry is 2 to 3 mm for all the "ingredients". I use a sieve to keep only the good parts of it.


    I would repot at the beginning of the spring. Keep an eye on the buds. As soon as they are ready to sprout, that will be the D-day for repotting.
     
  9. schusch

    schusch Active Member Maple Society 10 Years

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    André - thanks for your input. The use of a sieve sounds like a good suggestion to minimize the aeration problem Dale is referring to. Do you see any problem with a mix of smaller and bigger mulch pieces, though?
    As regards the composted pine bark: can you buy those, or do you compost your own? I see you live in France: if you buy them, any suggestions, names of brands, etc - I should have easy access to anything you can lay your hands.
    (Finally, I thought pozzolan and pumice were basically the same, the pozzolan being finer?)
    Thanks again.
    Schusch
     
  10. Andre

    Andre Active Member Maple Society 10 Years

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    Smaller can avoid draining, bigger is not good for the roots ramification.

    I buy it near Orleans but you can also do it in your garden by leaving the pine bark outside during 6 months.

    It's close but pumice has a better water retention.

    See all the informations here :
    http://www.plantes-carnivores.com/fiches_techniques/substrats/substrat_comparatif.php
     
  11. schusch

    schusch Active Member Maple Society 10 Years

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    andré- you meaning leaving it out now in a container in the open is enough for it to be useable in the Spring? Is there anything you'd add to it during that time, to help the aging?
    Thanks again for taking the time to help.
    Schusch
     
  12. Andre

    Andre Active Member Maple Society 10 Years

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    yes if your pine bark has the good size (2 to 3 mm pieces), spread it outside on moist soil during 6 month. Under our climate, that should compost it enough.
     
  13. schusch

    schusch Active Member Maple Society 10 Years

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    thanks. That sounds easy enough.
     
  14. milo

    milo Member

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    I have a question concerning the use of pine bark in containers: does pine bark, used in a container mix, need to be composted? What is the difference between composted and aged? I found this information on the Cornell U. Department of Horticulture website : "Wood chips, sawdust, and bark may be used after composting along with other composted organic constituents; an exception is pine bark, which does not need to be composted before use."

    Here is the link http://www.hort.cornell.edu/department/faculty/good/growon/media/select.html
     
  15. growest

    growest Active Member 10 Years

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    Milo--many growers here use fir/hemlock bark for their nursery container operations, sometimes blending in 10% municipal compost for extra nutrient holding capacity. The bark is mostly used fresh, tho some of it is composted. Doesn't matter much in my experience, as long as you supply a bit more nitrogen with the fresh bark. With the universal use of control release ferts in the container nurseries, nutrient deficiencies are now rare.

    These softwood barks, pine being another example tho not common here in S.W. Canada, are comparatively stable in the pot so don't necessarily need the composting step. The other advantage of using fresh is that it gives more porosity than the same material after composting.

    Swift drainage and good air porosity are the most important factors in commercial growing, since irrigation and fertilization are both quite easily easily controlled by the grower. As they say, you can reduce the amount of air in the rootzone, but never increase it once the plant is potted up...which explains the nurseryman's love of potting bark...

    All hardwood barks must be composted, or they will decompose quickly in the pot and rob nitrogen and possibly overheat.

    Glen
     
  16. milo

    milo Member

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    Glen-thanks for the information. Do you try to keep the bark pieces within a certain strict size range, or do you admit various sizes? I don't quite understand what you mean by

    you can reduce the amount of air in the rootzone, but never increase it once the plant is potted up...which explains the nurseryman's love of potting bark... ?

    Thanks.
    Milo
     
  17. growest

    growest Active Member 10 Years

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    Milo--potting bark is typically 1/2in minus, meaning whatever passes thru a half inch sieve, including some fine stuff as well as coarse (not bigger than about half inch).

    The saying about air in the mix...once the plant is planted into a pot filled with any media, all you could do, if you did anything, is compress that media more, which reduces the air (usually undesirable) but you can't uncompress it to increase the air porosity (which might be desirable, esp. as time goes on and the decomposition in there makes the mix heavier and less aerated). To make things more interesting, the plant roots themselves gradually fill a lot of the air spaces over time, making the root zone less aerated (one of the reasons you can rarely leave a plant in the same container for years and years).

    Sooo, the good aeration quality of bark is the reason it is favored for container media.

    Glen
     
  18. Gomero

    Gomero Well-Known Member Maple Society 10 Years

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    A good potting mix in B.C. may not be nearly as good in San Diego as good drainage is probably more important in a cool rainy climate.
    In my climate I've tried several ones, including some mentioned here. The best results, and the one I have adopted, is a home made mix that includes roughly 40% good garden loam, 40% coarse composted oak leaves and 20% pine bark. Adequate water retention during the period April to October is more critical than fast drainage during the winter. My mix has ample time to drain in between the sparse rains that fall around here.

    Regards,
    Gomero
     
  19. growest

    growest Active Member 10 Years

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    Excellent point, Gomero. I've gotta remember how cosmopolitan this list is.

    Just for fun, I'll share that it has been raining most days since early October here, with the outlook for more of the same for the next 3 months...we lose more container plants from rot than freezing most winters in S.W. British Columbia. Personally I'd prefer a climate closer to S.W. France...

    Glen
     
  20. milo

    milo Member

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    Many thanks to both of you. Pine or fir it is. I usually find pine straw recommended as mulch, so I guess fir needles would do the trick, too?
     
  21. Layne Uyeno

    Layne Uyeno Active Member 10 Years

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    Hi Glen,

    You might want to try what the bonsai people use in Hawaii. Mix in *rough* volcanic rock in your potting mix filtered through a 1/8" seive and use what's left in the seive. By volcanic I'm not talking about pumice or other other similar potting medium. The type of volcanic rock I'm talking about is very rough with areas where tiny bubbles left air pockets. Here it's typically found in Dracaena potting mix. There's red and black volcanic rock and either should work well.

    Aeration is very good with all the little air pockets and drainage is also very good. This should prevent your maples' roots from rotting during the rainy season, though you may have to water more frequently in the summer.

    Just a thought,

    Layne
     
  22. ikarijin

    ikarijin Member

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    Regarding containers over 15 gallon being expensive:

    I have been using 55 gallon food grade plastic barrels that are approximately 34" H. When cut in half, you have two 17" H x 22" in diameter containers with a yield of approximately 27 1/2 gallons. The barrels were purchased from Yoshida Foods in Portland, Oregon for $2- $5 each. (The price varies and is negotiable) As I live 45 miles north of Portland, distance was not a problem. I made 3 trips in one day- hauling 12 barrels per trip. This was several years ago. Since that time, they have been out in the weather without any damage from UV or other causes.

    I drilled 5 -3/8" holes for drainage and placed a sheet of plastic canvas (available at craft stores) over the holes and filled with fast draining soil mix. To insure these pots drain well, I have placed them on cast concrete squares- measuring 24" x 24" x 1 1/2 ". They are cast with a 9" hole in the center to allow water to freely drain from the pot. It took a little time to fabricate the molds, but so far everything is working well.

    And there you go...large pots for little cost. I hope this helps someone looking for inexpensive large pots.
     
  23. Andre

    Andre Active Member Maple Society 10 Years

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    Can you post a picture of one of these barrels ?
    Thank you
     
  24. Layne Uyeno

    Layne Uyeno Active Member 10 Years

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  25. ikarijin

    ikarijin Member

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    Hi Andre, Sorry for the delay in replying. Layne Uyeno posted a picture,The one from "Yankeecontainers.com" looks like them.I also ran across the same web site several years ago while looking for "Rain Barrels". In another search an article on how to make "Rain Barrels", listed Yoshida Foods as the source of the barrels the rest is history.Will try to find a picture to post if anyone is interested.
     

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