User avatar
smokensqueal
Green Thumb
Posts: 392
Joined: Thu Jun 26, 2008 5:36 pm
Location: St. Louis, MO Metro area

Fresh Wood chips/mulch

When the last hurricane brought some crazy winds to the MidWest it brought down some of my step dad's large trees. He's cutting up the large pieces for firewood but was planning on buring the brush. I found a chipper that someone is going to let me use and I was going to make wood chips out of some of that brush.

My question is can I use those wood chips as mulch right away or do I need to let them dry out? If I need to let them dry out how long do I need to wait? I was wanting to mulch my trees this fall and thought this would be a good use for the brush.

cynthia_h
Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

Go ahead and use them. The mulch available to me is shredded trees from my city's public works crews. They take the trees down, put them through the truck-mounted shredder, and dump the chips into the free mulch bin.

No aging.

I used copious amounts on my roses this year. No problems at all. Mulch performed as it was supposed to--keeping down weeds, extending the time between waterings.

Cynthia H.
USDA Zone 9, Sunset Zone 17

Charlie MV
Greener Thumb
Posts: 1544
Joined: Fri May 09, 2008 3:48 am

I've read and heard it's better to age. I don't know why. I have a chipper and if I need mulch, I don't generally age it. I have been hot compostimg and generally I can wait 3 weeks for it to cook so I use compost instead of mulch. Our neighborhood only hauls yard waste once a month so I'm really popular because I ride my lil tractor and trailer around and pick up all I can. It keeps the street clean and provides me with plenty of compost. To answer your question though, I don't see a need to age it either. I've never had a problem using un-aged mulch.

User avatar
smokensqueal
Green Thumb
Posts: 392
Joined: Thu Jun 26, 2008 5:36 pm
Location: St. Louis, MO Metro area

Thanks for the replies. I've been doing a little more searching and it looks like they should be fine for tree but there is conflicting results for flower beds. But that is fine with me my main concern was for putting it around trees. The few recommendations I found was that 1. don't put it on to thick. when they decompose they can get hot and damage roots and that leads me to #2. don't push it all the way up to the trunk. Again if it get's hot it can actually start to rot the trunk of the tree :cry: Other then that I couldn't fine a reason not to use it. Plus I found a good answer about "aging" them and found that it make no difference if you let them dry out they still contain the same amount of carbon as wet and will decompose the same. BUT if you let them age by not only letting them dry out but start to decompose then you don't run such a high risk of getting them hot around the tree but they will still continue to decompose and could generate heat.

Thanks again for the feed back and if anyone else has input feel free to add it. Thanks

cynthia_h
Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

I think the recommendation to keep tree trunks free of direct mulch contact has more to do with not providing a path for bugs to crawl from the mulch up into the tree AND to keep the trunk "breathing"--not in prolonged contact with water.

Of course, the mulch recommendation also assumes (oops...) that no walnut chips are being used. Use any walnut wood for your woodwork shop projects! But walnut is jealous of other plants and contains juglone, an herbicide.

My roses have been fine; this is the first year I've mulched them, and I was pleased at how the soil they're planted in stayed moist between once-a-week waterings. I was occasionally able to stretch the watering interval to 10 days!

Cynthia

User avatar
smokensqueal
Green Thumb
Posts: 392
Joined: Thu Jun 26, 2008 5:36 pm
Location: St. Louis, MO Metro area

Actually according to this research black walnut isn't a problem as thought. Juglone is only found in just the bark and fruit and not wood. [url]https://www.ext.vt.edu/departments/envirohort/factsheets2/landsmaint/jan94pra.html[/url]

But on the other hand this site states that is in everything but not nearly as toxic as in the root. But recommends NOT mulching with it next to the more sensitive plants.

[url]https://ohioline.osu.edu/hyg-fact/1000/1148.html[/url]

But I don't have to worry I'm not using black walnut.

User avatar
Jess
Greener Thumb
Posts: 1023
Joined: Mon Mar 19, 2007 11:50 pm
Location: England

The only problem you might have is a shortage of nitrogen in your soil.
The bacteria that break down the wood need nitrogen for the process. Better to use fresh woodchip in the autumn when your plants have less need.
Knowing without doing is like plowing without sowing."

User avatar
smokensqueal
Green Thumb
Posts: 392
Joined: Thu Jun 26, 2008 5:36 pm
Location: St. Louis, MO Metro area

Ya that's what I got from also but it's my understanding is fresh or aged are both going to need N to decompose. Just because it's aged doesn't mean that its not going to need N to decompose. I found that that's why you don't want to use any wood chips with shallow roots unless you supplement N. I read somewhere just add something with more N to the area before adding the wood chips and you won't be missing anything and once the chips are decomposed then they will return the N to the ground or to new wood chips.

fayettedawg
Newly Registered
Posts: 1
Joined: Wed Apr 01, 2009 1:40 pm
Location: Madison, MS

Bad results from using fresh wood chips

Our local landfill gives away mulch that has just been run through a chipper. It looked like a good thing to amend some clay soil where I was going to put a vegetable garden. I sifted out the big chucks of wood that were left and mixed it in my soil. I did this two years in a row and the vegetable garden I tried to grow in this spot had terrible results. Not a single squash or zuccini or tomato on any of the plants. Then last week, I saw the guy on "Gardening by the yard" talking about whether you should put wood chips and mulch from a freshly ground up tree in your garden. He said to never do this because as it decomposes, it will draw all the nitrogen from the surrounding soil. The light bulb went off and I finally realized why my vegetables had failed in this spot for 2 years in a row.

sweet thunder
Senior Member
Posts: 210
Joined: Thu Apr 02, 2009 5:43 pm
Location: Eureka, CA

I'm finding this really interesting as I am beginning to think seriously about a chipper of my own. The brush pile out back is growing much faster than it can be hauled away in my city's green waste containers, and I'm a pretty laissez-faire composter.

My big concern, though, is that a lot of my yard waste is invasive stuff like blackberry, holly, and ivy. Can I put these in a chipper and use them as mulch? Anything else that should be avoided?

MaineDesigner
Green Thumb
Posts: 439
Joined: Thu Nov 09, 2006 4:17 pm
Location: Midcoast Maine, Zone 5b

"Correct" mulch is one those issues that can prompt vociferous arguments among gardeners and landscapers. Although there are I few things I would quibble with I'm broadly in agreement with this blurb:
[url]https://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Myths/magazine%20pdfs/Woodchips.pdf[/url]
Chipping invasive plants shouldn't be a problem as long as you do it before they set viable seed.

The Helpful Gardener
Mod
Posts: 7493
Joined: Tue Feb 10, 2004 2:17 am
Location: Colchester, CT

MD, I agree with you that most of this is fine, but one big quibble I have is salient in my mind...
Evidence: Actually, many studies
have demonstrated that woody
mulch materials increase nutrient
levels in soils and/or associated plant
foliage. My hypothesis is that a zone
of nitrogen deficiency exists at the
mulch/soil interface, inhibiting weed seed
germination while having no influence
upon established plant roots below
the soil surface. For this reason, it is
inadvisable to use high C:N mulches in
annual beds or vegetable gardens where
the plants of interest do not have deep,
extensive root systems.
I would include perennial beds as well as I have witnessed backward growth from wood chip application first hand in several perennials (once had hosta dwindle from massive three foot across to a foot in two seasons) Plus most C/N counts I see find perennials and veggies at about the same needs. SO let's throw perennials in too. SO it's fine as long as we don't use it on annuals, perennials, and veggies...that's somewhat limiting, but not even vaguely surprising to me...

High carbon inputs (like wood chips) tend to make fungal, therefore acidic soils (yes, I know what the good doctor said, but she is talking about a small amount as amendment, not a forest woodland soil). High nitrogen inputs like grass and herbaceous materials tend to make bacterial, therefore more base soils...

We need both for good veggie and perennial and annual growth, but they like it a bit more to the bacterial side of things (F/B ratio of .75 to 1) Here we come with a load of wood chips, which shifts the biology toward the fungal end of things (both by innoculating and providing more suitable environment). Not a big problem until we start to get an F/B around 2, then we have unsuitable ratios for crops, but suitable for shrubs. Around 5 it is only suitable for trees...

It is not so much that the bacteria for wood breakdown NEED N as much as it is they ARE N (carbon combines with nitrogen to make amine groups, which combine to make amino acids, which combine to make proteins, which combine to make bacteria, protozoans, etc.) As that population gets bigger, they need more protein, thus more N, and they steal it and keep it (stingy little bacteria). We could release that N by providing a lot of bacterial predators (protozoa) to eat bacteria and poop nitrogen, but where could we find them?

That's right, compost. And for just that reason I only use uncomposted wood chips around trees and shrubs; just safer. Compost them for a while and the predators have shown up already, so the lock-up effect is already mitigated somewhat.

We are just learning (actually we were learning lots until chemicals showed up and everybody decided soil was just somwhere to put the roots) how nature does fertilization and it is a lot more complicated than we thought it was (I one asked Elaine Ingham how much we knew about soils and she shot back "A lot less than we know about our oceans". This from the Mike Dirr of soil biology). Living soil just works better than dead soil, and I wanted to give you all a peek into that world, and just why certain things behave as they do. SO... good question, and it all comes back to the soil, greens and browns, and working with Mother, not against her...

HG
Scott Reil

Return to “Landscaping”