Q. What is the purpose of using mulch in the garden?
Q. What makes good mulch?
Q. What do you use for mulch in your garden?
Q. When do I apply it, and how much should I use?
Q. Do I have to move the mulch before adding compost and fertilizer?
Q. Are cocoa hulls good for mulching?
Q. Can I use mulch made from recycled tires?
Q. Is black plastic or landscape fabric a good mulch?
Q. What about Ruth Stout’s mulch methods?
Q. Do you mulch your pots and other containers?
Q. What is the purpose of using mulch in the garden?
A. Mulch (such as bucketful, above, about to be spread) serves several purposes. It will not just suppress weeds and slow moisture evaporation, but should also break down into the underlying soil gradually and thereby improve the soil’s texture. A layer of mulch helps moderate soil temperatures. Mulch serves as a buffer from soil compaction caused by rain, and helps prevent the crusting-over of bare soil that can sometimes prevent moisture from being absorbed.
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A. This can be very confusing, particularly because what’s sold as “mulch” in many cases isn’t really very suitable for performing the full range of duties that I think mulch should accomplish (above). Briefly, I look for a material that is:
- An organic substance (meaning deriving from some living or formerly living matter);
- Fine- to medium-textured so it will break down into the underlying soil…
- …but substantial enough to stay put;
- Preferably aged before I use it;
- Dark in color (if for the ornamental beds);
- Available locally at a good price, preferably in bulk delivery unbagged;
- Not a source of contaminants, pests or diseases.
To elaborate: Any mulch I use in my ornamental beds must be fine-to-medium textured and dark colored so it looks good. Forget anything that’s going to sit there and never break down, like big hunks of bark (which I call “baked potato mulch” because they look like giant spuds sitting on the ground to me), or anything that’s bright orange. I am completely opposed to dyed mulches.
One caveat: Very fine-textured materials like sawdust do not make good mulch as they cake and fail to decompose.
Why use a product that has been aged or composted before you use it as mulch? That extra step really makes a difference in the mulch being ready to do its job as a soil-improver. Wood products in particular may also rob soil Nitrogen while decomposing, unless composted first (before they’re spread as mulch).
I used to use bagged mulches, including cocoa hulls and various bark products, many years ago. I have since switched to local materials I can have delivered in bulk, sans plastic bags (and minus all the fuel used in processing and trucking of bagged stuff across the nation to my local garden center). Environmentally, it’s important to buy locally when you can, especially with bulky items.
Technically, plants can serve as a sort of living mulch as well; that’s why certain ones are termed groundcovers.
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Q. What do you use for mulch in your garden?
A. On my ornamental beds, I use is a composted stable bedding product–a local agricultural byproduct from horse or dairy farms that has been allowed to age first. It’s simply wood shavings (not too fine, not too coarse, as you can see in top photo) that farmers spread on the floors of animal stalls to absorb manure and urine, and then muck out and compost afterward to recycle it. I expect you can find a local source via your county cooperative extension office; this website give a sense of the kind of product I am talking about, though I buy from a local farmer.
Leaf mold (partially rotted and shredded leaves) would also be great, if your local landfill offers it, or start a leaves-only compost pile in fall and pre-shred it like this.
In my vegetable garden, I use straw (which is of course not dark-colored), preferably chopped. In rough areas such as along the roadside outside my fence, I will use wood chips from the power or phone company, or from a fallen tree. I will also use wood chips or bark chips on utility-area pathways (behind sheds, between vegetable rows). I pile up wood chips and let them age before using them.
For more details about pros and cons of different mulches, try the Cornell Cooperative Extension mulch website.
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Q. When do I apply it, and how much should I use?
A. I mulch my perennial and shrub beds in spring, but not until after the soil has a chance to warm and dry a bit. I also am conscious of areas where I want biennials and other self-sown plants to have a chance to do their thing; mulching these too soon may prevent successful reseeding.
You want a 2- or 3-inch layer, generally speaking, and if you use the right stuff, about half of that will work into the underlying soil before you go to replenish in fall or the next spring.
Keep the mulch a couple of inches away from trunks of trees and shrubs; never pile it up, volcano-like, against them, as that can invite pests and diseases.
Anytime I work in an area and disturb the mulch, I add a bit more rather than leave bare spots. I apply mulch to new beds whenever I plant.
Mulch is sometimes also used in winter in cold zones to help keep newly planted things in the ground, or to shield tender plants from damage (such as the graft union on roses). For that purpose, materials like evergreen boughs (which would not normally be good for mulch) may also be used.
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Q. Do I have to move the mulch before adding compost and fertilizer?
A. If you use a mulch that has the correct texture and has been composted first, this should not be a problem. I simply “topdress” (spread compost and all-natural organic fertilizer right on top of last year’s partly decomposed mulch) then replenish the mulch as needed.
The problem with most mulches, even bagged shredded bark, is that they haven’t been composted before they are sold and/or are too coarse, so they don’t break down very well, but rather form a sort of coating on top of the soil.
Good mulch, on the other hand, breaks down and improves the soil below. I don’t mean it breaks down in a week or a month, but over the course of a season or two.
If you have a thick layer of mulch that’s not breaking down nicely, and the layer is just getting thicker and thicker each year, rake some away and them add your amendments and start using a new, better-quality mulch this year on top of that.
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Q. Are cocoa hulls good for mulching?
A. I used to use bagged mulches, including cocoa hulls, many years ago. I have since switched to local materials I can have delivered in bulk, minus the plastic bags. There is no cocoa-processing plant nearby and hence no local source of this recycled product.
Cocoa hulls can be very high in potassium, which can be a problem for some plants in some soils, and they may be toxic to pets (particularly dogs) if they are swallowed. So those factors added to the “buy local” environmental argument put them on my “no” list today.
Additionally, cocoa hulls are hard to spread and either blow away or clump together if the bag got wet (sometimes they can be moldy in damp weather, too). However, they have many of the qualities I want in a mulch: They are dark in color and fine textured and look good on the beds.
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Q. Can I use mulch made from recycled tires?
A. To me this seems a real environmental no-no–yet another wacky thing that is being tried out on us unsuspecting consumers. Yes, it’s re-using worn tires…but putting them into the landscape, and nature, in shreds is as bad or worse as piling them up at the dump whole. They don’t break down and become incorporated into the soil, so they’re no good, and even dangerous. Remember that animals and much smaller living organisms interact with and inhabit the soil–I don’t think a worm wants to process tire shreds while making worm castings, or a robin wants to rustle around in the tire litter (though they love the leaf litter!).
My rule: To be a mulch, it must be organic (a living/formerly living material) so it can decompose over time and return to the soil, not taint it. The one exception to my mind re: the organic rule would be some stone materials used in certain zones and certain types of landscapes.
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Q. Is black plastic or landscape fabric a good mulch?
A. Black plastic can be used to heat up an area (such as for sweet potatoes or pumpkins) but should not be left in place as it prevents moisture from entering the soil and otherwise interferes with soil health. Roll or fold it and reuse the plastic year after year.
Landscape fabric, or so-called geotextiles, are not a substitute for mulch. They should not be used in garden beds, though they may have a role as a weed-block beneath gravel of pathways or patios, for instance.
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Q. What about Ruth Stout’s mulch methods?
A. Long before phrases like “lasagna garden” were making the rounds of the as-yet-uninvented internet, Ruth Stout (author of “Gardening Without Work,” 1961) was layering all her organic materials on top of her soil—sheet composting, as it might be traditionally called. Her tactic served to thwart weeds, reduce the need for fertilizers, conserve moisture and spare her the work of composting in a conventional heap with all the toting and turning of materials.
Her approach to gardening starts with the foundational principle of applying mulch, mulch and more mulch, and then simply moving it back a tiny bit each year a bit to make room for a row of seeds rather than all that turning and tilling (and weeding).
She said the “aha” came one spring when the plow man hadn’t come yet to till, and she was eager to get planting. She saw that the asparagus (a long-lived perennial vegetable crop) was already up and growing, right through the layers of fallen leaves and such. “I walked over and said to the asparagus, ‘We don’t have to plow for you; why do we have to plow for the other vegetables?’” Stout recalls. “And the asparagus said, “You don’t.’”
Where do you get all that mulch? The garden creates it, or at least some of the raw material that becomes it: spent cornstalks and uprooted pea vines and the like, to which Stout added fall leaves and also bought-in straw or hay (“spoiled” hay was fine, and cheaper; don’t worry about a little decay, she said).
More on Ruth Stout’s methods (plus video of her) is in this post.
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Q. Do you mulch your pots and other containers?
A. I do apply mulch to the soil surface in my containers, to help keep roots cool and keep moisture in. Depending on the plant, I may use composted stable bedding or a small stone (pea stone).
Do you have any mulch recommendations when artillery fungus is a problem? We were told to ‘mulch’ with stones but I really don’t like the look of that but I also am not fond of little spots all over my house.
Hi Lesley. I don’t know much about it so I just read this Penn State University Frequently Asked Questions page, and this pdf from Cornell. I am OBSESSIVE about using only mulch that has been well-aged by composting BEFORE it arrives at my site, which is said in both documents to reduce the issue. I don’t bring any wood chips/shavings/other products into the garden that are not composted thoroughly first for this and many other reasons.
I like to mulch with the neighbor’s leaves that they conveniently collect, bag, and place at the end of their driveway for me to pick up. (How handy!) Well, they don’t realize it, but I still thank them for their services. Anyway, I have fungal issues in my vegetable garden every year, and I can’t “move” my garden as is normally recommended because I live in a neighborhood full of tall trees with only one sunny spot in my back yard. I am concerned that by using my neighbor’s leaves I may be introducing more “contaminants” to my garden such as fungal disease spores, but aren’t these things floating around in the air in our neighborhood anyways? I was wondering if leaving them inside their black plastic bags for a while would help kill off some of the fungal visitors (it’s pretty hot in East Texas, even in the fall). Any thoughts on the pros and cons of neighbor’s leaves as mulch?
Just like Angela above, I am wondering how you know if your compost is contaminated? Anything with livestock manure could have residual herbicides in it that would actually harm plants (the hay the animals consumed could have been sprayed ) and I have read that piling it up or composting it actually makes the herbicide take longer to degrade.
Just like Angela above, I am wondering how you know if your compost or mulch is contaminated? Anything with livestock manure could have residual herbicides in it that would actually harm plants (the hay the animals consumed could have been sprayed ) and I have read that piling it up or composting it actually makes the herbicide take longer to degrade.
I have a gardening neighbor who uses sweet peat to mulch. I’m not even sure what it is but I understand it’s a non-renewable source which, for me, would also make it a no-no. Any comments?
interesting about sweet peat b/c I hd a few Master Gardeners tell me that was the best kind of mulch to buy.
My neighbor’s tree drops alot of pine needles in my back yard. Are pine needles good mulch for vegetables? Does it add too much acidity to the soil for other plants, such as fruit trees? In the edible-free front yard, I’ve been pulling the weeds but they are overtaking my garden. I would hate to resort to chemicals but they are becoming more appealing for the ease of use and because I have a large space to cover. Please advise!
Hello Margaret, please may I enter the discussion. I really enjoy the comments and continue to learn from all. I have a large garden and mulch continually. Before laying down the mulch each year I water and then fling ! handfuls of blood and bone over the area, then lay down the mulch.Usually Lucerne hay, stable straw or shredded bark, never, never the dyed stuff.
I like to ruffle up the mulch a little bit in areas were it is possible, think it allows the air into the layers and keeps the soil fresher, do you think this is a good idea?
I do use newspaper in areas that are not too visible, but find it takes a long time to break down, is there anything I could put with it to speed up the process?
URGH! I just bought and put down cedar bark mulch (recycling the plastic bags).
However, I “broadcast” in fairly lightly so I can hand-mix some peat moss with it. Does this redeem the bark a bit?
I also use pebbles in service areas of the garden (like hose area) to hold soil, and to create low-labor pathways.
Thanks, as ever.
P.S. Related to Jack! he looks great on the colorful circle patterned rug.
Maybe a jacket in that rather than a classic tux? Like Lionel H. might have worn playing the xylophone?
Hi, Judith. I like to fluff up the mulch if it’s sort of matted down in some spots, and I top it up with fresh as needed. As for the newspaper, besides moistening it with the hose thoroughly after applying, before topping with mulch, I don’t know.
When two large douglas firs were taken down, the limbs were chipped. The pile sat for about three months, about 8 feet deep, occasionally watered, but the Hood River Oregon heat dried it out. No nitrogen was added. That chipped (limbs, bark, needles) mulch has been spread 3-5 inches deep over an area that we are now, 5 months later, getting read to plant. Given your comments about un-composted mulch, what would you recommend? Scrape it all up (100 x 30 feet), about 6 -8 cubic yards (yikes!), or can we top it off with a nitrogen fertilizer? Chicken manure? (My wife sent me your article, with an ‘I told you not to do that’ admonishment. Thanks
I don’t use wood chips or other coarse wood products on my beds for vegetables or flowers, Daniel — only on pathways. Frankly, I don’t even use them on my beds if they are well-aged — wood just doesn’t “feed the soil” by breaking down gradually in place the way I insist a mulch does. Wood shavings that animals (cows, horses) have used as stable bedding, that then has been composted thoroughly (turned regularly, etc.) yes, but not chips/chunks.