What Are Your Favorite Compost Materials?

Root Simple’s new composting game for your Xbox!

I wish I could source compost pile materials from our yard. But lead and zinc contamination in our soil make that a dodgy proposition without doing a lot of expensive lab tests. And I never seem to have enough materials even for our modest vegetable garden. So in the past I’ve used:

  • horse bedding
  • chicken manure from our own chickens
  • alfalfa hay (kinda spendy these days)
  • straw (takes a long time to break down)
  • spent grain from a local brewery
  • vegetable scraps from the farmer’s market

Once again I’ve got to build another pile and I’m interested in hearing from readers about compostibles you’ve used. Do you have a good source for stuff to compost? What are some of the things you’ve managed to scavenge? Comments!

Tips on Composting from Will Bakx of Sonoma Compost

Sonoma Compost’s composting operation.

On Thursday at the National Heirloom Exposition, Will Bakx, soil scientist and operations manager of Sonoma Compost, gave a rapid fire lecture on the nitty gritty details of composting. Here’s some of his useful tips:

Temperature and Turning
Compost should stay above 131ºF for 15 days to kill pathogens. Bakx recommended getting a thermometer to check the temperature every day during the initial period and using Sonoma Compost’s handy Temperature/Turning Sheet (pdf) to keep track of the temperature of the pile. If the pile dips below 135ºF, turn it. If it doesn’t get up to temperature, add more nitrogen containing materials. If it gets above 163ºF, add more carbon containing materials. After the initial turnings just let it sit unless you have to turn to add moisture.

Bakx believes that you should turn as little as possible, just enough to achieve that first period of 15 days above 135º F. I really like the simplicity of this method and will definitely use the turning sheet the next time I build a pile. I really makes it clear when you should turn and how often.

Moisture
Lack of moisture, according to Bakx, is the number one mistake made by beginning composters. He suggested an ideal moisture range between 40-­‐60%. You can check the moisture level using the following technique:

Take handful of material. Squeeze firmly
Water escapes: >60%
Shiny ball: 55%–60%
Ball remains when tapped: 50–55%
Ball falls apart when tapped: 45–50%
No ball forms: 40–45%
Unless hand feels powdery dry: <40 p="p">

Bakx has drip irrigation set up on his large windrows, something I might try with my pile the next time.

Pile Size
The mimimum size for a compost pile is 3 x 3 x 3 feet or larger.

Things not to add

  • Ash–our soils tend to be alkaline in California and ash will raise pH. A small amount is ok.
  • Cardboard–Bakx is afraid of the glues and said that he is very conservative about what he ads to his compost.
  • Toilet paper–because of metals (I’ve been unable to verify this–if any of you know about this issue, please leave a comment.

Alleopathic plant material such as eucalyptus leaves and walnut leaves, on the other hand, are ok to add. Bakx cited studies where plants were successfully grown in leaf litter made entirely out of eucalyptus leaves. He suggested keeping such alleopathic material to less than 15% of the pile.

Web links
Sonoma Compost’s website: www.sonomacompost.com
Sonoma Compost’s Simple Guidelines to Composting (pdf)
Sonoma Compost’s Temperature/Turning Sheet (pdf)
An online carbon/nitrogen ratio calculator

Comopost, Compost, Compost

As if I didn’t need a reminder of how important compost is to a vegetable garden, note the tomato above. It’s on its way out, but it grew with no supplemental water in hard-packed clay soil contaminated with lead and zinc in a hot side yard. Why did it do well while the rest of my vegetable garden did not do as so good this summer?

Homemade compost.

I didn’t have enough compost for the rest of the veggie garden so I bought some at a nursery. The homebrew compost obviously had much more life in it. 

And life is the point. Soil is a living thing. Plants, particularly vegetables, need microbial life to thrive.

For more on the importance of microbial life read the USDA’s soil biology primer written by Dr. Elaine Ingham.

Does the scent of compost make bees angry?

I think I’ve stumbled upon a strange phenomenon: the smell released by turning compost pisses off bees. Yesterday was the third time this has happened to me. I took a sting just underneath my eye and another one to my right hand when I was turning a pile located about 15 feet away from a hive. Coincidentally, the same thing happened to a friend yesterday: he got stung while working with compost near a hive. Ordinarily our bees are reasonable about living in a small yard with humans–they are not even very aggressive when I open their hive. But apparently turning compost near them is a different matter.

I look like I’ve been in a fight. Lots of Benadryl today.

I have a theory. Bees are incredibly sensitive to odors and use them to communicate. Their alarm pheromones alert the hive to predators such as bears and people. Bee alarm pheromone consists of many different compounds. Interestingly, a lot of these compounds such as n-Butanol and Isoamyl acetate are byproducts of fermentation processes. I’m guessing that a number of these compounds are present in compost, and that when you turn a pile the act releases a cloud of compounds that mimic the bee’s alarm pheromones, causing them to attack.

It turns out that other lifeforms like to mimic honeybee alarm pheromone. Some species of orchids mimic bee alarm pheromone in order to attract pollination services. Small hive beetles, who raid beehives for their pollen, apparently bring with them a yeast that causes a fermentation process that mimics alarm pheromones. The small hive beetle’s fermented alarm pheromone, in turn, attracts more small hive beetles who quickly overwhelm the hive. These sorts of deceptive, symbiotic and parasitic loops in nature really amaze me. 

As a side note, I’ve only had compost pile related bee stings at this time of year, when honeybee numbers are at their peak and pollen and nectar sources are getting scarce (summer is hot and dry in Los Angeles and not much is blooming).

If you don’t have a hive, I doubt random, foraging worker bees would go after you if you are just turning compost in your yard. But if you’ve got a compost pile and are thinking about installing a hive–or vice versa–I’d seriously consider keeping the two as far apart as possible.

Am I alone in noticing this compost/bee alarm pheromone issue?

Composting at the NATO Protests in Chicago

Have you ever gone to a concert or a convention or some other large event and marveled at the staggering amounts of waste generated? I’ve been particularly wishing more of that waste was composted. And what do you know? Just as I was thinking about this, guest Root Simple blogger Nancy Klehm happened to send me a post on this very subject. If only every event had a compost tsar! Here’s Nancy:

I am obsessed with urban soil health, so when I got a phone call in mid May from Steven of the Seeds of Peace Collective, I realized a soil ship had floated in. Seeds of Peace is a collective of accomplished cooks and trained street medics, based in Missoula, who provide delicious home cooked food in support of non-violent social movements. They were in Chicago to set up a free community kitchen to serve thousands of NATO conference protestors. Steven said they needed my assistance with their food waste as they had already overwhelmed a small urban garden’s compost bin.

It was late, so I waited until morning and drove my pickup to their site – a parking lot between a community center and an auto parts store. The scene was impressive: a maroon biodiesel school bus with windows dressed in curtains screen printed with frying pans and butcher knives and the largest wok and cast iron pan I have ever seen. A purple tent stretched from the bus into the lot overhanging a to-code outdoor kitchen with multiple burner stoves, wash sinks, prepping area and boxes of produce, mostly organic. At least 12 people stood prepping food for the day. Gallons and gallons of salad and stir fry ingredients were being tossed and mixed in 30 gallon coolers with small wooden oars.

Every day for a week, I picked up the 100 or so gallons of food waste a day and provided them with extra large garbage cans to pour their waste into. Their kitchen was three miles from the rallying area. Once the food was prepared, they would pack a flat bed with it and a few tables and trundle off to the park to serve their healthy, delicious food free of charge.

One pick up was an entire garbage can of delicious looking chickpea and sweet potato curry that had fermented in the sun due to the police blocking their passage to the Park. It made me cry to compost that delicious looking curry. I had to use a couple of bales of straw and dumpstered cardboard from my carbon stockpile to take care of so much nitrogenous waste. Over the past month, the pile, well integrated and covered with a thick layer of straw reached thermophilic temperatures and now is in its mesophilic stage. Most of the food is just residual moisture now and the pile has dropped in volume by at least 20% due to composting and evaporation. So much future soil!

Thanks Steven, Sarah, Patrick and the rest of you of the Seeds of Peace Collective. May you meet with strong hearts and hands on the road.