Pine bark mulch-good or bad?

I use a LOT (20+yds a year) of wood chips in my gardens, nursery beds, orchard. Some I get for free from arborists, some I purchase from local firewood processors. A local lumber mill has piles of shredded bark mixed with wood fragments, pine bark mulch without the aging and dying of the comercially produced mulch. This stuff seems pretty nice, it is a nearby source that fits in with a commute I regularly make, and they load it into my pickup for a reasonable price of $12.
I am wondering if there are any drawbacks using it instead of other woodchip-type materials.

The biggest issue I see with pine bark is that it can lower your soil pH. In my area it is recommended that fine pine bark be mixed into the soil when planting acid loving plants like blueberries. I also use pine mulch to top mulch my acid loving plants like azaleas. Pine mulch seems to break down a little quicker than hard wood mulch but if it free, then no big deal.

1 Like

My soil already tends towards acidic pH, so I should perhaps top dress mulched areas with wood ashes or lime, and also a nitrogen source.

I personally would not worry too much about pine bark acidifying your soil. I’m not saying it’s a myth but from what many people say it has a negligible effect on soil pH. I’d certainly use it if you can get it.


Perhaps this article will be helpful:

It does not directly deal specifically with pine bark, but it suggest arborist wood chips are one of the best mulches, and superior to bark mulch and other wood products.

It also dispels some of the things I’ve heard about mulches changing pH and taking nitrogen from the tree.

But if you don’t feel like reading the article, I’d say the article suggests that pine bark is not a bad mulch for your trees, but the arborist wood chips would be better.

If you do have access to the arborist wood chips, maybe get as many yards of that as you can, and mix in the pine bark to come up with the amount you need?


We get a lot of mouse/vole damage with organic mulches so we try to keep tree rings clear.

It is excellent. Just keep it an inch or two away from the trunk, or the varmints will girdle your trees without the hawks having been given the opportunity to see them emerge and snatch them.


Friends don’t let friends heap mulch up to the trunk. I try to keep a 3-4’ circle clear around mine.

My concerns with using this raw pine bark/shredded wood material are- the acidifying potential, pine volatiles like turpine and whatnot negatively affecting the soil, and getting crushed by the massive loader that dumps it into my truck.

To be safe, I just wouldn’t mulch near your house - as it (especially pine mulch) provides a better habitat for termites…

Termites don’t use mulch as a food source, but they do take advantage of the moist, warm environment that mulch creates. The termite species that are likely to infest a mulched area are largely subterranean, and the mulch overhead helps to ensure that the soil they live in remains moist and is protected from extremes in temperature.

Some types of wood are preferred by termites, while others can act as a deterrent or even be toxic to these wood-eaters. Cypress sapwood, loblolly pine and slash pine are favored by termites. Cypress heartwood, melaleuca, eucalyptus, southern tidewater red cypress and California redwood decrease a termite’s chance of survival when compared to a standard food source, such as white birch.

I disagree with that, my pine bark last 2 or 3 times longer than hard wood, which breaks down super fast if you ask me.
I use pine bark in all my 125 containers, it is the main ingredient, what great stuff!

1 Like

I use wood chips in all my mixes for my large collection of container trees…for probably the last 10 years…it breaks down very quickly. I still continue to use it because its super cheap (free) and its nice and light.

No termites in Maine, carpenter ants though…

Bark is not the same as chips and is more resistant to decomposition- I think partially because it repels water.

I also think soft wood will break down quicker than hard simply because it is less dense. Also, I believe that the idea that conifer wood chips are acidifying is unfortunately a myth, even though sawdust makes a fairly acidic soil mix, but once it is broken down it becomes close to neutral. There may be some acidity created at the interface but the soil will not be appreciably altered pH wise in my experience. If you search for it I believe you will find researched evidence supporting this, if not I will be happy to be corrected- just got back from work and don’t feel like looking it up. . .

I have read university publications along the line that Alan and others have mentioned. That pine bark has little to no affect on soil acidification. Pine bark used in container mixes does affect the potting mix pH to some extent in the short term. Personally I see no reason not to use it in the manner you currently do.

Right and I meant that pine bark lasts longer than hardwood bark, not chips of either. In my experience even hard wood not bark breaks down quickly. I never had soft wood chips, so have no idea? I do know pine bark lasts a long time.
The reason i said bark, the original poster is talking about bark, not chips. So I wanted to let him know pine bark is long lasting. Again great stuff in any form for a multitude of uses.
I admit I didn’t word it well, pine bark is the best thing you can use if you ask me, even un-aged or uncomposted, it’s fine to use as mulch. As a soil amendment, you have to use composted. Well you don’t have to, add more nitrogen to the area if uncomposted. So it’s not good, it’s a great product to use. The dirt doctor hates pine bark, but that’s his problem! I’ve been using it for over 40 years, it’s great!

You are right- I didn’t even look at the original topic and was responding to someone else’s wording of just pine mulch. I never buy bagged products because I use so much volume and getting loose delivered by the yard is the way to go. Shredded wood made from arborist chips run about $20 a cubic yard here.

no close sources for bulk bark mulch here in nd, looking for a cost effective container mix for propagating bushes and trees. found a source for Douglass’s fir fines about 400 miles from here. what do u guys pay for shredded/ground bark? this place wants $40/yard. i can get wood chips delivered for $100 / truckload which is about 18 yards but that won’t work for what i need…

Fir is as good as pine. I can’t comment on price, not sure? I love using the stuff, but it is only one of 4 items I always use in container mixes. I use a 3-1-1-1/3 pine, Pro mix (general peat mix). compost, DE the size of perlite.

No it won’t! Still good stuff to use where you can.

I know @Drew51 is a fan of pine bark. I’m putting some blueberries in containers and decided to use pine bark. I need to do more research to determine if it is worth it. Here is the result of a two year study with southern blueberries in 10 and 13 gallon containers.Effect of container size, substrate composition, and genotype on growth and fruit quality of young southern highbush blueberry in a container-based intensive production system - ScienceDirect
" There were no effects of the percentage of substrate components (50 to 100% pine bark, 0 to 40% coco coir, or 0 to 10% perlite by volume) on plant height, yield, or fruit quality. Similar results were reported in strawberry that using pure pine bark and pure coconut coir did not produce significant difference in yield, crown size, or fruit quality (Cantliffe et al., 2007)."
The assumption was that water and fertilizer had to biggest effect and the study was only 2 years so longer duration is unknown…

There are plenty of dead pine trees here. I decided to collect some bark for container planting and run it through my wood chipper. It handled 8 inches pieces of pine park ok.

1 Like