Vegetable Garden Mulch

Discussion in 'Fruit and Vegetable Gardening' started by Pilar Spratt, May 16, 2020.

  1. Pilar Spratt

    Pilar Spratt New Member

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    Hi, I'm starting my first vegetable garden and was advised that composted bark mulch would be fine. I have since done some reading and I'm getting mixed information. I have already purchased several bags of it. What do you think of composted bark mulch in the veggie garden?
     
  2. Puddleton

    Puddleton Active Member 10 Years

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    If the bark is fully composted then it should be fine.
    If it's not completely composted then add additional manure beneath and above the mulch.
    This will help balance the possible effects of nitrogen drawdown
    I prefer using premium lucerne as mulch on vegetables and similar gross feeding plants
     
  3. Durgan

    Durgan Contributor 10 Years

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    Bark takes long time to compost and it is usually quite large, probably not ideal for vegetable garden. I use soft tree mulch.
    2 June 2018 Mulch Covered
    Posted on June 2, 2018 by Durgan
    2 June 2018 Mulch Covered 2 June 2018 Mulch Covered
    All cultivated areas of the garden are now covered with wood chip mulch. All small bushes have a thick layer round the stems. This is to retain moisture as much as possible. Ten yards were used all transported from the driveway to the garden area by wheelbarrow. The garden vegetables are all protected by mulch. If weeds show the mulch is raked aside and the weeds removed. Mulch inhibits weeds somewhat but many get through. It took about nine days to move all the mulch.
    [​IMG]
     
  4. Puddleton

    Puddleton Active Member 10 Years

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    A couple of items
    That material is nowhere near composted.
    Nature continually tries to decay wood into compost then eventually humus.
    In order for wood to decay, the micro organisms and fungi need nitrogen to feed on so they can digest the cellulose and other "woody" matter
    The process of composting demands more nitrogen.
    The nitrogen is taken back from the plants to feed the composting process. (nitrogen drawdown)
    Dargan is probably applying more nitrogen to the soil to keep the gross feeding vegetables growing whilst the woody mulch is decaying.
    Wood & bark based mulches work very well around shrubs and some fruit trees.
    Any plant that grows and dies quickly such as annual or perennial vegetables need a lot of food from the soil for a healthy life cycle.
    Consider spreading lucerne hay beneath the woodchip on your vege's.
    The lucerne will feed your soil and rapidly increase useable organic matter while the bark will help to reduce evaporation.
    Once the season has ended the bark should have decayed sufficiently to eliminate n drawdown.
    Dargan. suggest not spreading thick mulch around stems of plants.
    It encourages diseases such as collar rot, phytopthora and other nasties.
     
  5. Durgan

    Durgan Contributor 10 Years

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    I sprinkle a bit of urea N when rototilling the chips into the soil. One year and they have disappeared. There has never been any indication of lack of nitrogen on the plants. My growing season is about four months frost free. Seldom do I consider the soil, weather takes over before soil becomes an issue. Seldom have any irritating disease, probably due to lack of sufficient moisture. Periodically a few annoying insects cause misery but controllable. I use mulch mostly for moisture retention, seldom do I have to water, and when I do I use rain water collected in barrels.

    I only started using heavy mulch about ten years ago. At first experimental. Now I get ten yards every Spring and find it marvelous. Bare earth grows nothing, which I believe. Season is too short for cover crops most years.

    I am a voice in the wilderness, since seldom do Canadians grow vegetables even if they have an area to do so. And most know nothing about preserving.
     
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  6. Margot

    Margot Generous Contributor

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    Welcome to the Forums, Pilar Spratt. When you ask what we think of composted bark mulch in the veggie garden, we need to know whether you are planning to use it on top of the soil to supress weeds, conserve moisture, etc. or whether you're thinking of using it as a soil amendment.

    Maybe, like Durgan, do you plan to start out with it on top of the soil one year and then mix it in the next? Even composted (ie. incompletely composted) bark mulch does not pose much of a challenge to nitrogen availability when placed on top of the soil. " . . . there is a nitrogen deficiency at the boundary between the mulch and soil, which probably inhibits weed seed germination." https://www.researchgate.net/profil...ape-mulch-WSU-Extension-Fact-Sheet-FS160E.pdf
    However, mixing 'composted' bark mulch in with the soil before planting is a different story because it will tie up the available nitrogen while it continues to decompose. I doubt this is what you are thinking about. Either as a mulch or as an amendment, I don't think composted bark mulch is the best choice for a vegetable garden. Even if it were, what one company calls composted bark mulch may not be the same as what another company sells. Besides that, it has a tendancy to compact. All it really is is bark mulch that has sat around for awhile. And you don't know what tree(s) the bark is from.

    Premium lucerne (aka Medicago sativa, aka Alfalfa) sounds like an interesting product (although it may contain weed seeds) but I wonder how available it is to home gardeners throughout Canada. Some people use hay or straw as a mulch; keeping in mind that hay contains more weed seeds than straw.
    The difference between hay and straw in the garden
    Our local vegetable gardening guru in westcoast BC, Dr. Linda Gilkeson, recommends ordinary fallen leaves from deciduous trees as a mulch.

    Not to trivialize the use of mulch in vegetable gardens, many gardeners I know don't use a mulch at all.
     
    Last edited: May 17, 2020
  7. Puddleton

    Puddleton Active Member 10 Years

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    Hello Margot
    Check out stockfeed suppliers for premium hays such as lucerne or what you lovely northern cousins call alfalfa (it's funny as we put alfalfa sprouts in our salad)
    If you've got a racehorse industry nearby then you've got access to premium alfalfa (lucerne) hay.
    It's worth sourcing and using on vege's, roses and perennial borders.
    It's dynamite for encouraging beneficials, retaining moisture and generally feeding the good guys in your soil
    It's essentially mulching with a green manure crop.
    By spreading it monthly under the roses, we control blackspot.
    The hay mulch covers the fallen diseased leaves and is consumed quickly through the composting process.
    The black spot spores seem to die off with the decayed diseased leaves
    We're still in drought here so a bail of premium costs up to $25.
    It's still worth it in my eye's (but I'm biased for roses)
    1 bail will easily cover Dargans Leek border for the year (10 ish m2)
    I agree with you about the perils of hay.
    1 bail of cheap "garden" hay or straw = years of pasture weeds.

    I just checked your classifieds
    Here's the treasure at a dazzling $6 a bail.
    You lucky ducks.
    Can you mail me a few bails please? tee hee

    If London or St Catherines is nearby, then give it a go.
    You'll have the best roses, perennial and vege's in town.
    Avoid it on Camellia & Rhododendron as it can burn their roots.

    DEFINATELY AVOID CHEAP HAY.

    Hay for sale | Livestock | London | Kijiji

    Hay for sale | Livestock | St. Catharines | Kijiji

    [​IMG]
     
  8. Durgan

    Durgan Contributor 10 Years

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    My first mulch was hay and it coagulates so much that moisture could hardly penetrate. Same with straw. Wood chips work well for me. I must get ten yards for $120 delivered to my driveway next week after planting. That is about 70 wheelbarrow loads to wheel back.

    I tried alfalfa and it was not suitable, one year it grew and was a misery to eliminate. Usually it didn't grow enough due to short season. Wood chips left to rot in a pile for one or two years is idea,l buy even fresh they are good for top moisture retention and they rot well in a year or so.

    Leaves make a inconvenient mulch. They do not stay in place and are miserable to work wih.
     
    Last edited: May 18, 2020
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  9. Sundrop

    Sundrop Well-Known Member

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    By definition " A mulch is a layer of material applied to the surface of soil."

    Organic mulch will not cause nitrogen deficiency in the soil since the nitrogen needed for decomposition comes from the air that consists of 78.09% nitrogen.
     
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  10. Puddleton

    Puddleton Active Member 10 Years

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    Organic mulch will not cause nitrogen deficiency in the soil since the nitrogen needed for decomposition comes from the air that consists of 78.09% nitrogen.

    With all respect Sundrop.
    your rationale is misinformed

    Yes composted mulch won’t demand N as much as non composted.

    Yes. Nitrogen comes from the air but it needs to be converted into salts to become available for plants to uptake via osmosis. The salts need to be dissolved in water to pass to through the roots membranes. Little if any N is respired from the atmosphere.

    There are micro organisms in the soil that absorb atmospheric N but I’ve yet to meet a plant that breathes nitrogen. (This doesn’t mean there’s no plants that do)

    Check out literature on carbon / nitrogen ratios for composting.

    Wood chip “on” the soil is just as demanding for nitrogen as wood chip “in” the soil

    Fungi, bacteria, actinomycetes & a myriad of other decomposing treasures that we’re still learning about or yet to be acquanted with, have a massive appetite for N. So much so that they draw nitrogen back out of plants.

    Continuous moisture hastens decay but gardening in dry times requires extra thought.

    Check out the link below for solutions to deal with managing available nitrogen levels

    Using Mulch - Combating Nitrogen Drawdown

    Decay is a fascinating area of the science.
     
  11. Puddleton

    Puddleton Active Member 10 Years

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    With regard to durgans hay or straw coagulating.
    When spreading it. Ensure you tease the pieces apart. It also goes much further.

    it sounds like you’ve placed it out in it’s compressed form.

    Keep the cheaper hay & straw bales for hay bale gardens (my grandmother showed me this 20 years ago)
    . Use premium lucerne for minimal weeds

    check this out

    Straw Bale Gardens - The Permaculture Research Institute
     
  12. Margot

    Margot Generous Contributor

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    Sundrop - you and I know the definition of 'mulch' but I wasn't sure what Pilar Spratt meant by "composted bark mulch would be fine." Fine for what? It is conceivable that someone could purchase a product called 'composted bark mulch' and use it as a soil amendment.

    I was trying to make my answer as thorough as possible.
     
  13. Margot

    Margot Generous Contributor

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    Not to be argumentative; just for the sake of discussion . . .

    Dr. Linda Chalker-Scott (Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist), one of the foremost authorities on home gardening here in the Pacific Northwest, has long been an advocate of planting shrubs and trees in unamended soil with a very thick layer of wood chips on top. According to her research, there is very little nitrogen loss in the interface between soil and mulch and the potential loss of N can be mitigated by first spreading compost over the soil before the mulch is applied.

    FROM Washington State University Extension: USING ARBORIST WOOD CHIPS AS LANDSCAPE MULCH
    Q: Won’t wood chip mulches tie up nitrogen and cause nutrient deficiencies in plants?
    A: No. Many studies have demonstrated that over time woody mulch materials will increase nutrient levels in soils and/or associated plant foliage.
    However, there is a nitrogen deficiency at the boundary between the mulch and soil, which probably inhibits weed seed germination.

    Add a thin underlayer of compost. Before installing wood chips for the first time, create a thin underlying layer of a more nutrient-rich mulch (like compost, if there are concerns about nutrient deficiencies.) This “mulch sandwich” approach is a logical one that mimics what you would see in the mulch layer of a forest ecosystem. It’s not required, though, and over time a wood chip mulch will develop this same structure as the lower layers break down

    (PDF) Using arborist wood chips as a landscape mulch. WSU Extension Fact Sheet FS160E.
     
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  14. Durgan

    Durgan Contributor 10 Years

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    I am familiar with compostd bark mulch in the Okanagan. It is heavy and takes about five years to even start reducing. Weeds learn to grow though it readily. It is for all intents an purposed useless as a vegetable garden mulch.

    Straw Bale Gardens - The Permaculture Research Institute

    When inexperienced I read with great interest about Permaculture. The epitome being
    "Back to Eden"

    Pursuing it for a few months I arrived a the conclusion that it was hocus pocus. BS in other words. Right up there with upside down tomato planters or roof top gardens on apartment highrises. I notice most of the Internet entries have disappeared.

    Gardening is a practical effort and a serious gardener doesn't make more labour than is necessary.
     
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  15. Sundrop

    Sundrop Well-Known Member

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    I hate to continue this discussion but I have to correct one more misunderstanding:
    We are talking here about the organisms that decompose mulch, not about plants or plant roots.
     
  16. Puddleton

    Puddleton Active Member 10 Years

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    Hi Sundrop.
    Apologies & thanks for clarifying your nitrogen comment. I read it as the plants breath it directly.

    Hi Margot. i agree with you & Linda Scott about mulcing with woodchip on tree & shrub borders.
    The depletion of nitrogen at the soil interface makes sense around woody perennials.

    My comments were based on the original context of discussion, which was using it around gross feeding plants such as annuals & vegetable borders.

    I agree, There’s nothing better than wood or bark mulches around trees & shrubs.

    Hi Durgan.

    Hay or straw gardens work.

    The systems of permaculture work

    Pursuing a natural system or cycle for a few months then dismissing it is a little premature.

    Granted. Your growing season is quite short.
    It’s possible that a hay garden might not be ready for planting until the following year.
     
  17. DavidB52

    DavidB52 Member

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    In addition to the information provided by other posters, I'd like to add that it also depends upon the specific plants you have.
    And your purpose.

    Do you want to add some organic material to the soil immediately for the current growing season? You might be better off with manure. Local nurseries and hardware stores (Superstore, RONA, Canadian Tire, etc.) set up gardening centers in the spring and summer months offering a range of composed manures. Perhaps one of those would be better for immediate soil improvement.

    Usually, when I think of mulch, I think of something meant to be added on top of the soil in the Autumn to provide some protection to the plant over the winter. Extra insulation, which will then break down over the years and eventually build up the soil.

    What plants are you planning to put it around? Depending upon what plants you have, they may not like certain types of bark mulch.
    Every fall, I spread about an inch of aged cedar bark mulch around the base of a Fig Free, Asian Pear tree, and several other plants in the vegetable garden. My intention is to give the roots some extra insulation in case we get an extra deep freeze over the winter. I am in no rush for it to break down, the trees gets other food and manure, so that is not a consideration. However, blueberry bushes do NOT like cedar bark mulch. They prefer clean pine sawdust. So, they get some clean sawdust spread around them. If you have a source of sawdust (no treated wood or chemicals), you may want to try that. BC has sawmills everywhere, so it should be easy to find some.

    Also, if you can, you may want to make your own compost with a compost bin. Many municipalities offer them (the City of Coquitlam sells them for $25.) Or you could try to source one from somewhere else. Then you could use all the vegetable scraps from your own kitchen, and garden clipping, to create your own compost and you know exactly what is in it.
     

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