Strong Smells from the Pile

Phoenix, AZ

I compost with rabbit droppings (which I don't actually need to compost but as it comes with a whole slew of other things like hay & newspaper I do it anyway). The poop doesn't smell but the urine really does. And for some reason its REALLY bad at my new house. Perhaps the air flow was better at my previous house because it use to take a few days to calm the smell down, and now its a lot longer then that. I'm wondering if there's any tricks out there to keep the smell down to a minimum? Only the urine smell - something that's safe for the pile. I put dirt on it and that helps (it helps to break it down faster, too) & I'm thinking about putting plastic bags over it tonight, too. Is baking soda safe & effective? I was excited a couple of weeks ago as I saw a black soldier fly crawl into it, but I've seen no maggots since. I'm worried that I'm going to get my neighbors fed up with me.
Help!? (PS the smell is not from a stagnant pile - if anything its hard to keep a stand alone pile wet enough here in phoenix for it to turn stagnant). Thanks!

Phoenix, AZ(Zone 9b)

meisgreen, I cover my compost pile with a thick layer of straw. Would that work for your problem? I especially like the straw because it's easy to pitchfork on and off without turning it in.


Everett, WA(Zone 8a)

I don't have any GOOD ideas, but here are some ideas:

Just a guess: would it be possible to soak most of the urine into paper or some other "brown"? Any ammonia-like smell I usually associate with excess N, or perhaps a LOCAL excess of N.

Adding paper or browns to urine for immediate C/N balance might help it be changed before it gave off too much stink. Also, just adsorbing it onto paper might hold in some of the smell. And maybe the paper could be added at the very source: right where the urine accumulates.

If you have some other compost pile, or soil, with a different ppulation of microbes, you might give that a try, instead of whatever soil you're already mixing in as innoculum. Just a long shot, but maybe you are adding bugs that tend to release ammonia!

It sounds like you already know all the tricks:

turn the smelliest raw parts under deeply
get enough air to the raw parts
make sure the raw stuff is mixed with rapidly-metabolizing and rapidly-growing microbes
balance C and N so you don't have excessive N
avoid excessive water but have enough

Here's a real long shot: change the rabbit's diet to something with more carbohydrates and less protein.


Virginia Beach, VA

Put some baking soda then cover with tarp.

Phoenix, AZ

I was wondering about the baking soda. Hmmmm

Virginia Beach, VA

I use baking soda a lot and if you have costco, bj's they have a large bags and are cheap. Bellie

Phoenix, AZ

I heard that it cuts down on the acidity of the pile, maybe slowing decay?

Virginia Beach, VA

,It will not slow down the breakdown if it is covered with a tarp.n the breakdown of the pile if it is covered with a tarp.Belle

Everett, WA(Zone 8a)

I've read in a few places that anything that reduces compost heaps' acidity (like lime) encourages loss of nitrogen by making any the ammonia evaporate faster.

(Lime and maybe baking soda would convert ionic NH4+ that can't evaporate into neutral, gaseous NH3 - very able to evaporate.)


I also know that, as a kid, I tried to compost pine needles for years and got nowhere until I added a little lime, which turned it all to black, usable compost in just a few weeks.

Virginia Beach, VA

I get fascinated reading your answers. Are you a chemist? A's Chemistry?Chemistry was not my strong points in College but excelled in Math and Pharmacology. LOL!!!

As I posted previously against norms that I compost everything including stuff from freezers so I use baking soda a lot. My bins are at the back of the yard hidden behind the shed and before they smell i pour baking soda. I use thick grill cover.


Everett, WA(Zone 8a)

>> Are you a chemist?

No chemist would say so! I write software now, but was into biochemistry and organic chemistry in high school and college. I always try to qualify what I say with "I read this somewhere" unless it is very widely believed. If it just something I've observed or "seems to work for me", I try to be even less doctrinare. Everyone's climate, soil and practices are different, so what works for one may be poson for another.

For example, almost everyone who does winter sowing seems to think it's so easy that it's foolproof. Well, they just have not yet met a big enough fool (me). Maybe after my seocnd or thrid try I'll get it right.

>> I compost everything including stuff from freezers

I think that's smart. I've started adding small amounts of meat (like cat food left in his dish, or half a pack of hot dogs that got old). Even though my pile is small and cold, I haven;t seen any downside yet, not even evidence of attracting rodents.

Maybe baking soda isn't a strong enough base to cause loss of N through ammonia loss.
Maybe some N is lost, but not enough to smell.
Maybe a small chnage in pH changes the balance of what microbes grow, and reduces the stink-producing kind.
Maybe losing some N would be a good thing, if rabbit poop and pee are TOO N-rich.

(One thing about baking soda: it does add some salt (sodium bicarbonate). If it is just the pH that helps the smell, and not dry baking soda's odor-absorbing property, lime would add less sodium.)

(I was thinking of suggesting that meisgreen try a big excess of "browns" to cut down on odor, especially burying the sitnky bits UNDER the paper or sawdust or brown leaves. Isn't the usual ratio quoted as 30:1 brown:green? Anyway, try more brown, and then later add a little more N if that seems desirable. See what happens.)

Maybe the people who say "NEVER lime a compost heap" are just wrong, or working under conditions where it is important, but the conditions where baking soda helps odor are different conditions.

One thing I like aboiut gardneing even more than science: gardening is real-world, which means "complicated". Science has to simplify everything as much as possible, trying to make things SO simple that they can be analysed and repeatable.

Sometimes that is like looking for a lost contact lens under the streetlamp instead of where you lost it "because the light is better over there". But "real scientists" are modest and humble, and relakze that they are struggling to understand wonderfully complex (Mother Nature) with tools that are simple. Only arrogant short-sighted button-counters masquerading as scientists think they know it all, or even know enoguh to make doctrinaire statements.

Thats my opinion, anyway! When you don't know, you DON'T know.


Phoenix, AZ

Thanks for your help. I've noticed the smell going down on its own - as does happen after a while (its just particularly bad when there's an air inversion going on in my yard and the smell just stays). I DID pile lots of plants on top of the poop and then dirt on top of that, which did seem to help.

The poop itself does come with lots of brown already - like the bedding (Yesterday's News is the bedding that's used ((its recycled paper that's formed into pellets)), in addition to hay). I actually get rid of lots of the sheets of newspaper because there's so much of it. Also, here in Phoenix, its so dry that when paper isn't more finely shredded in drys up too much so I can't use it to cover the pile. If not composted properly it will never break down. But I MIGHT be able to use a tarp, which would keep lots more moisure in anyway

I think pee just smells (yeah, I know, DUH). I tell you my roses LOVE it!

Savannah, GA

Mine got very rank awhile back. It smelled like a bum that never took a bath! I was afraid it was going to smell when it was time to break it up but it didn't.

Now it doesn't bother me when it smells because the pile cooks faster. As long as I can't smell it from far away it's Ok.

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