Growing Garlic: Using spent kitty litter pine sawdust and coffee grounds as amendment

I ran a little impromptu experiment on my garlic crop this year. I put in 2 beds last fall:

1. 'Silver rose' softneck, amended with a mixture of coffee grounds and the sawdust left over when the kitty litter pine pellets break down to sawdust (rich in nitrogen) + compost tea
2. 'Early Italian' softneck, amended with only compost tea

Nearing harvest time:


The result: The Silver rose produced a bumper crop (65 bulbs!). The Early Italian entirely failed to germinate.

Silver rose bulbs, hanging to cure:


Silver rose bulb:


Besides the variety factor, which I admit could be a significant factor here, the only difference was the amendment. Using the spent pine pellet kitty litter sawdust/coffee grounds mixture is a perfect permaculture move. I'm diverting both products from the waste stream and using them to nourish crops, which means I can avoid outside inputs as well. The poop, incidentally, is removed and added to a hot, min. 6-month compost. Sawdust never touches the vegetables at harvest. It's added at planting time, breaks down completely, and is no longer present at harvest.

Read the full details here: 65 Bulbs of Garlic on the Wall...

Harvest shot:


Anyone else trying something similar?

thanks for sharing! my kid has pet rats and we have a bounty (?) of pine sawdust pellets with potentially disease-ridden urine and poo that I quite frankly don't know what to do with. I've been just dumping them on out-of-the-way garden paths for now as weed suppressant but hadn't considered mixing them with coffee grounds, letting them sit, and using them as a substrate. I tend to avoid root veg (my soil is clay and rocks) but this might be an interesting experiment.

Respectfully, I have deep concerns about the safety of the methods proposed here. Caveat emptor.

I composted sawdust-based cat poop for a decade, but never believed it safe to use for food crops in the garden proper, and especially not ground crops. I could not control the conditions well enough to guarantee food safety. It was fantastic fertilizer for shelterbelt trees though.

My information is that cat parasites can only be destroyed by consistent temperatures of 165F (74C). That is hot enough to cause third degree burns. There is no way that every part of a homestead compost pile would reach these temperatures. It certainly doesn’t happen in living soil.

When making choices, I believe it is valuable to gauge information against a credible source. This document gives a rather sobering view of the potential problems.  https://www.cdc.gov/parasites/toxoplasmosis/gen_info/faqs.html

The only safe method I can think of, in a homestead environment, would be to boil the litter/poop in a metal container. This would ideally be an outdoor adventure, mindful of the prevailing breeze. Naturally, this would utilize waste heat during a char making session (stacking functions). The resulting material would be wonderful food for the organisms in healthy soil. I would not hesitate to eat that garlic.

I did a whole lot of research to allay that concern beforehand. Our cat is indoor-only, and therefore highly unlikely to contract the disease in the first place. The feces, as I mentioned, is removed and put into a hot compost for a minimum of 6 months before it's ever used on the soil as compost (and this is a separate method I've only just begun; I hadn't used this compost on the garlic bed). You have a better chance of getting toxoplasmosis from raw meat and unwashed fruits and veggies, by the way.

Source: Cornell University Feline Health Center

Because cats only shed the organism for a short time, the chance of human exposure via cats they live with is relatively small. Owning a cat does not mean you will be infected with Toxoplasma. Since it takes a minimum of 24 hours for T. gondii oocysts in cat feces to sporulate and become infective, frequent removal of feces from the litter box, while wearing gloves and washing hands afterward, minimizes the possibility of infection. It is unlikely that you would be exposed to the parasite by touching an infected cat, because they usually do not carry the parasite on their fur. It is also unlikely that you would become infected through cat bites or scratches. Indoor cats that do not hunt prey or consume raw meat are unlikely to be infected with T. gondii. In the U.S., people are much more likely to become infected by eating raw meat and unwashed fruits and vegetables than by handling cat feces. The possibility of infection after gardening in soil that has been contaminated with cat feces also exists, and this possibility can be mitigated by wearing gloves and by washing hands after gardening.

But feel free to avoid using spent kitty pine pellets this way, if that's your comfort level.

I respect your choice. My only intent is to encourage anyone considering this to have 'eyes wide open' and act with an abundance of caution.

My cats were avid night-time mousers, so the risk profile was different. Since I had tons of fruit trees and shelterbelt trees, it made sense for me to use dodgy compost in those locations.

Happy growing!

Hi Lisa! I’m wondering if you’ve done any more experiments and how it’s going? We have 6 indoor cats so have 6 pine litter boxes and trying to find out what to do with all of this sawdust.

Hi, Manda!

Yes, I've continued this method for many years now, and it's a key aspect of our compost system. The sawdust goes to a bin outside as soon as the box needs fresh litter, and this sawdust gets incorporated into the soil with the use of a broadfork. Haven't had any issues.

Excellent. I have a couple questions on implementation:

How do you keep the sawdust from clumping and becoming anaerobic in the bin?

Do you let it get rained on a few times or anything specifically in the bin or before adding into the soil? Do you compost it in-ground or in a compost pile?

Do you mix it with anything specific or just compost it? Like, coffee grounds? Paper? Plant matter? Or just general composting material?

I have so much excess litter sawdust that I am trying to figure out a way to keep it from becoming a wood block.

Anyway, any tips are appreciated!

Manda, answers in-line below:

Manda Bell wrote:Excellent. I have a couple questions on implementation:

How do you keep the sawdust from clumping and becoming anaerobic in the bin?  

Never had a problem with this. It sits in an open watering trough outside. It gets rained on constantly, and I've drilled holed into the bottom of the trough to drain it. The sawdust sits there until the trough is full, and then the sawdust gets incorporated directly into the soil via broad fork and pitchfork hand-tilling. It doesn't clump. We have clay soil, and our garden beds are rich and wormy after many years of this.

Manda Bell wrote:Do you let it get rained on a few times or anything specifically in the bin or before adding into the soil? Do you compost it in-ground or in a compost pile?  

See above re: rain. We do not compost this. It sits in the trough, gets rain-rinsed, and then it goes directly into the soil.

Manda Bell wrote:Do you mix it with anything specific or just compost it? Like, coffee grounds? Paper? Plant matter? Or just general composting material?

Nope - I don't make this more complicated than it is. We used to add coffee grounds only because we needed an easily accessible place to dump coffee grounds coming from my husband's coffee habit, and the sawdust trough is located right outside the basement steps for easy disposal from the cat litter box. My husband kicked the coffee habit, so we no longer add coffee grounds, but even without those, the sawdust-as-soil amendment is good use of a substance that would otherwise go to a landfill.

Manda Bell wrote:I have so much excess litter sawdust that I am trying to figure out a way to keep it from becoming a wood block.

Granted, we only have one cat, but I don't see how you could get it to become a wood block. Sawdust will remain dusty unless you glue it together in an industrial process to create particle board, I think!

Manda Bell wrote:Anyway, any tips are appreciated!

Sure thing. After I return from a much-needed hiatus, I'll be covering our whole compost-and-soil enrichment system in an upcoming post on Brunette Gardens, if you're interested. Much luck to you!

Excellent. Thanks for all the info. I was curious if you made a simple or complicated process for this.. certainly doesn’t seem like it could me any more simple to me. Other than dealing with the sheer volume of pine leftovers I’ll try implementing something very similar. Appreciated! Cheers

Edit: if it weren’t for this litter we would make very little trash. That’s why I’ve been trying to find a better (i.e., useful!) method of disposal.