Wood As Soil Amendment

Discussion in 'Soils, Fertilizers and Composting' started by Junglekeeper, Nov 18, 2005.

  1. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    Wood in the form of bark chips or shavings is often used as a soil amendment.

    1. Which woods are better than others for this purpose?
    2. Which woods should NOT be used because of their negative effect on plants? (I believe alder is one such wood because of its resin.)
     
  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Never heard of any problems with alder wood.

    Ones to avoid: any species that are not being sustainably harvested - primarily cypresses, thujas
     
  3. jimmyq

    jimmyq Well-Known Member 10 Years

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    not sure what would be a better choice but I think I would shy away from Walnut and Cedar (Thuja plicata & Xanthocyparis nootkatensis).
     
  4. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    Sorry - my mistake in citing alder. These questions may be specific to citrus plants. A vendor's website recommends using redwood or cedar but against pine and spruce. I thought their recommendation would apply to other plants as well.
     
  5. mr.shep

    mr.shep Well-Known Member 10 Years

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    I think a lot depends on what soil type we have,
    our soil and water pH and what types of plants
    we want to grow.

    In the case of container grown Citrus, I have
    to believe several web sites are using the
    same source to recommend one part sand,
    one part peat moss and one part pine bark.
    There is one online reference that makes
    the qualification of using composted pine
    bark.

    For us here the issue is not so much the peat
    and the composted pine bark but more so the
    sand. The type of sand and where it is from
    will matter as many of our fine sandy soils
    are notorious for being hosts for nematodes.
    I've used coarse sand in my soil mixes for a
    lot of container grown plants for years with
    no ill effects but I would not use a bona fide
    sand unless it was a sandy loam from areas
    near me just because of the nematode issue.

    Personally, I would use a composted ground
    fir and ground pine bark combination along
    with a little perlite and fine silt for container
    grown Citrus. Peat and sand for me here are
    optional if I have the silt but can be and have
    been included in the soil mix. Then there is
    the issue of whether the container plants will
    be grown indoors or outdoors as the amount
    of peat, sand and perlite used will indeed be
    different.

    If it were me, my preference would be to use
    a fine silt instead of either or both sand and
    peat whether the Citrus is to be grown indoors
    or grown outdoors. I want soil in my outdoor
    mixes if I am using hose applications of water.
    I will not want any peat for Citrus as the peat
    will compact too much for me here from hose
    applications. I want air movement in the soil
    which is why I add in a little perlite along with
    the silt and the ground fir and pine bark instead
    of using peat and sand.

    Jim
     
  6. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I should have qualified my questions by saying the soil is for use in a container and that the starting point is standard sterilized potting soil that includes peat. Another author recommends using shavings from hardwood and not softwood. I guess it's because the former is slower to decompose.

    Is it worth the trouble to use wood shavings? It would complicate fertilization since the shavings will tie up an undeterminate amount of nitrogen which has to be compensated for. It also raises the question of whether soil pH will be affected. Wouldn't (more) perlite be a good alternative to wood shavings as it doesn't have all these issues?
     
  7. mr.shep

    mr.shep Well-Known Member 10 Years

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    A standard potting soil with perlite already in the mix
    will not require additional perlite to be added in for
    indoor growing. Where we mess things up is when
    we add in a heavy soil and mixing to the potting soil.
    Then, we may want to add in more perlite to aid in
    better drainage.

    Here is an idea of what I used when I bumped the
    5 gallon Citrus up to 15 gallons. There is a potting
    soil I've been buying at a mass merchandizer nursery
    that has a lot of ground fir and ground pine bark in the
    mix. There is peat and some sand in the mix also but
    not enough for me to worry about, even with hose
    waterings. There is plenty of perlite in the mix that can
    easily be seen. The soil at this location is quite gravely
    and I added in three heaping shovel fulls to 2 cubic feet
    of potting soil and then mixed them together by hand.
    Then I added in some fine grade Orchid bark (not cheap
    in price I might add) at the rate of two 3 pound coffee
    cans full to the medium and mix it in by hand. Why I
    like the bark in my mixes is so that the soil will not
    compact for me as readily. Another thing to consider
    is that we do not generally see the effects of a root
    rot fungus (we can still see water mold forms though)
    from soils that are not compacted in some way. The
    less compacted the soil, the less amount of root rots
    we will have to worry about. For indoor, in a home,
    container grown Citrus root rots may be our worst
    enemy.

    Redwood shavings added to a potting soil mix will
    not tie up as much Nitrogen as the author suggests.
    For outdoor growing of Citrus the redwood shavings
    can give us a long term benefit that is not always
    pointed out in that with environmental factors
    working the breakdown of the shavings will give
    us an equivalent of a timed release fertilizer. For
    in a home growing of Citrus the shavings will not
    tie up nearly as much Nitrogen if we use a liquid
    supplemental fertilizer every now and then. I
    would not worry about using redwood shavings
    for indoor, greenhouse and outdoor Citrus.

    Then again I am not a big fan of providing more
    Nitrogen than the Citrus may utilize. Much of
    our Nitrogen applications is wasted giving us
    the impression that we need more to compensate
    for the wastage and the Nitrogen that will be
    sucked up in the wood bark by adding in more
    Nitrogen than we probably should. Timing
    of the fertilizer is more important to me than
    the amount of Nitrogen we want to apply. I
    know what some studies recommend for a
    ratio of 3:1:1 but a lot depends on what our
    climate is, our soil, the soil and water pH
    the soil temperature and how much organic
    matter we already have in the soil. In some
    areas the plant may only use up a 1:1:1 ratio
    so by incorporating in a 3:1:1 automatically
    we tend to waste a lot of Nitrogen that has
    to go somewhere and much of it is simply
    wasted as it will get leached down through
    the soil before the plant can use it all. We
    stick to what makes the plant happy, not what
    some book author feels the plant should have.
    Personally, even in a commercial Citrus grove
    we can get by with half amounts of Nitrogen
    throughout a growing season if we know when
    to apply it and when those applications are more
    likely to go to waste for us. For in a home Citrus
    growing you may find that Nitrogen applications
    can be cut in half if you use the right soil mix
    with some soil added into the mix. If you add
    in some soil to your container every year you
    may not need to apply a lot of Nitrogen or apply
    as often anyway. With too much Nitrogen available
    to the plant you will have a reduction in the amount
    of flowers you will see during the year. If you want
    a nice lush looking houseplant then by all means go
    ahead and apply the standard rate of Nitrogen but
    if you want fruit then you may want to cut your
    projected amount of Nitrogen in half.

    Jim
     
  8. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I would be adding an orchid mix to the potting soil if not for the high cost. At one point I considered using orchid bark chips which is much more cost effective but didn't know what type of tree bark it was and whether it would harm citrus. Would it be safe to assume what's safe for orchids is safe for citrus?
     
  9. mr.shep

    mr.shep Well-Known Member 10 Years

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    I add in the fine grade Orchid bark to give texture
    and to allow for better air movement. In this case
    what is good for Orchids with the supplemental
    addition of this type of bark, whether it is the fine
    or medium grade will be okay for Citrus. The
    Orchid bark I have at both locations is a ground
    fir bark.

    Yes indeed a one cubic foot bag of the fine grade
    Orchid bark costs almost as much as three 2 cubic
    foot bags of the potting soil I am using. If you can
    find a fine grade of redwood walk on bark, that can
    work as a substitute for the Orchid bark.

    Jim
     
  10. Ron B

    Ron B Paragon of Plants 10 Years

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    Bagged amendments are much more expensive than bulk. To compare, remember that there is 27 cubic feet in a yard of bulk material.
     
  11. I use wood waste in an agricultural setting both as a soil amendment and growin
     
  12. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    By bulk do you mean a BIG package similar to that in which peat moss is sold? Where does one buy bulk?
     
  13. jimmyq

    jimmyq Well-Known Member 10 Years

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    Some garden centers have a bulk soil products area, they load your truck with a tractor or you can dig and fill the bags yourself froma big pile of stuff in the parking lot.
     
  14. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I've seen material in large packaging at Home Depot. However I'm reluctant to use it since it's not sterilized for indoor use. It's too bad since the price is good.
     
  15. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    Jim, what is your idea of fine, medium, and coarse grades? It looks like I can get fir bark on special order at a reasonable price. Which grade would be best for amending a potting soil that contains a fair amount of peat - fine or medium? The potting mix also contains some sand and various grades of perlite.
     
  16. Millet

    Millet Well-Known Member 10 Years

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    For me, I have found the very best "wood" chip additive to use for citrus is Coconut Husk Chips (CHC). I use 4-parts CHC (1/4" and 1/2" size) to one part coarse peat moss. Coconut husks chips absorb up to seven times their weight in water, do not degrade like pine and fir chips, have a usable life span of 5 -7 years, therefore do not reduce nitrogen from the medium, has a natural pH of 6.5 which is ideal for citrus, provides surpurb aeration and drainage. The last five citrus trees that I potted, I substituted ground coir for the peatmoss. Coir resists compaction much better than peat, and also aids in the correct pH. I don't believe you could over water a citrus tree when grown in a 4:1 CHC/peat or a 4:1/Coir medium. In the last couple years numbers of container growers that I am aware of have switched to this mix with excellent results, and I have yet to hear of a single complaint. For me, it has been an extremely good mix. CHC is somewhat expensive, but I have always believed you get what you pay for. - Millet
     
  17. mr.shep

    mr.shep Well-Known Member 10 Years

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    I'd feel better to see how the fine and medium
    grinds differ but from the grinds I've seen here,
    considering we want to mix the ground fir bark
    in with an already mixed potting soil, I would
    go with the medium grade for indoor growing.
    The fine Orchid bark is a little too fine and it
    will decompose faster than the medium Orchid
    bark but the medium grade is a little too large.
    I'd prefer a one to one mix of both grades but
    geez, what an expense just for a supplemental
    additive to a potting soil. I used to be able to
    get a forest humus that was ideal for me in
    that the grind was almost one to one fine
    and a medium grind which I used as my basis
    for my potting soils that I made on my own
    for years. Now I cannot get that forest humus
    unless I buy a similar grade in bulk, loose -
    not bagged, from a landscape supplier source
    and then the smallest quantity I can get is 1/2
    yard. So when we buy 7 yards of that humus
    for the misses planters every four years I have
    some left over for use in my potting mixes.

    Millet's suggestion of Coconut Husk Chips
    is something you may want to check into.
    I cannot comment too much on these as I
    have not used them but I do plan to check
    into them and see sometime how they will
    do for outdoor container growing. If I see
    some available I will give them a try out as
    an experiment. Too bad I already bumped
    up the misses Citrus from five gallons to
    fifteen gallons already. I am curious to see
    how well the Coconut Husk Chips might
    work for Japanese type Maples.

    Jim
     
  18. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    CHC sounds like a very good medium for all the reasons cited. I'm somewhat limited by the material I have easy access to. I suspect CHC is available somewhere in the city in some hydroponic shop if I really searched for it but I tend to take the choice of least resistance (I must be cheap AND lazy - LOL :) Having said that I wouldn't mind trying it if I can get my hands on some locally. I'll make an inquiry on my next visit to the nursery.

    Millet,
    The following are two in-depth articles (with pictures!) on CHC. They were written for orchids but much of the information would also apply to citrus.
    Agree? Disagree? What are your thoughts on these?

    It occurs to me that CHC may not work as well in my situation. Since I'm growing trees indoors I cannot water by top filling then allowing the excess to drain - imagine the mess on the floor. And since the medium will not be flushed on a regular basis I'm worried about the salt contained in the CHC. Would this be the correct conclusion?

    Not only that but there's the matter of storage; pots, trays, and other supplies have already found their way into my hallway, kitchen, and bathroom.
     

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