How To Manage a Compost Pile Using Temperature

compost temperature chart

I’ve always been confused about when to turn a compost pile. Some people suggest lots of turning while others don’t turn at all. I built a pile in December using a technique I learned from Will Bakx, soil scientist and operations manager of Sonoma Compost. Bakx recommends keeping the pile between 131° F (55° C) and 163°F (72°C) for a period of 15 days. The only time you turn is when the pile starts to dip below 131° F or to prevent the pile from going above 163°F.

The technique is simple–all you do is take the temperature once a day with a compost thermometer and write down the result on a calendar. The graph above is the result that I got from a pile made out of horse bedding, chicken manure from our hens, plant materials, straw and brew waste from a local brewery.

The red area on the chart is the thermophilic temperature range (135° -160° Fahrenheit). The dip you see at day 15 is the one time I turned the pile so that I could keep it in the thermophilic range. Using temperature as a clue to when to turn the pile has a number of advantages:

  • You can make sure that the pile does not get too hot. Above 160° F  you start to kill off the thermophilic bacteria that decompose your pile. To decrease temperature you turn and add more carbon material and water.
  • Washington State University recommends subjecting all of the pile to temperatures above 150° F to kill potential pathogens. I’m fairly certain that, with the turn I did at day 14, all of the pile got up to 150°F.
  • Weed seeds are killed above 130°F–another reason to watch temperature.
  • Failing to get high temperatures can be an indication of too much carbon or a lack of water. To correct, add more nitrogen and water and turn.
  • A loss of temperature could indicate that the pile is going anaerobic. The solution is to add more carbon material and turn.

Once the pile has had 15 complete days over 131° F you just let it sit. Compost is done when it is dark, smells like earth and you can’t recognize the original ingredients. It will likely be several months before it’s ready to use. I’ve found that I need to turn the pile periodically and add water after the initial thermophilic period due to our dry climate.

The mass of the pile is a factor as well–I’ve found that it needs to be a minimum of one cubic yard of material to start with. So I save and scavenge materials that I can use to build a pile all at once. The small trickle of kitchen scraps we generate each day goes into our worm bin.

Despite the geekery with using a compost thermometer, I’ve found that this method saves labor. Back breaking turning only happens when it’s necessary.

Hay Hooks–The New Hipster Accessory?

With so many city chickens I predict that hay hooks will become just as indispensable to the urban hipster as is the fixed gear bicycle. After years of hauling staw bales up the 30 steps to our house (to use as bedding for the chickens) I just broke down and bought a pair.

A vaquero at the feed store intervened with a neat tip when he saw me struggling to use my new hay hooks to load some bales into a friend’s truck. Here’s what he showed me. Note the red arrow in the photo above. Odds are with new hooks that this distance needs to be shortened a bit. My hay hooks were much easier to use after the feed store guy bent them using one of the anchor points in the truck bed.

In addition to the steps, my other reason for owning hay hooks is that I have to navigate bales down a narrow side yard. Hay hooks make the maneuver above a lot less awkward.

Now when will we see Bianchi come out with the hay hook equivalent of the Pista?

Ladies of Manure 2013 Calendar

Just when our Kickstarter fatigue has reached terminal limits, this crazy pitch shows up in our mailbox to make our day. Two words: Humanure Cheesecake.

(Err…two words you really don’t want to see together, ever,  now that I think about it. Sorry.)

As teachers, we spend a lot of our time trying to convince people to mulch and compost. Return it all to the earth, people!

We’re particularly fond of throwing down the humanure* gauntlet, partially because it really is a very important subject,  and partially for the shock factor and the giggles. Some audiences are primed for this challenge. For others, it’s the first time they’ve ever heard of the concept, and by the look on some faces, I imagine them thinking:

  • “Nope. Not even if civilization is burning down around my ears.”
  • “Note to self: Never visit these people at home.”
  • “They want me to keep poop around the house. Poop. Around my house.”
  • “Hmm, I’m sensing some sort of potty-training trauma here. Definitely an unhealthy anal obsession.”
  • “Funny, they don’t look like hippies.”

It’s an hard nut to crack, the poop nut. This environmental non-profit called The Fertile Earth Foundation is going about in a bold way, by trying to make manure sexy and fun. To be fair, the calendar isn’t all about humanure. (Then it would have to be called Jenkins Girls Gone Wild or something.) It’s about composting of all sorts, but humanure certainly gets much more play in it than it does in your average cheesecake calendar.

Take a look. They’re doing a Kickstarter to raise printing funds. What do you think? Think it will turn people on to the wonders of decomposition? What do you think it will take to make even basic composting a more commonplace activity? Do you humanure? If not, what keeps you from doing so?

*If humanure is new to you, check out the Humanure Headquarters for everything you could possibly want to know.

Aerated Compost Tea: Does it Work?

There’s a lot aerated compost tea brewers on the interwebs!

I’ve been asked by Urban Farm Magazine to write a short piece on the pros and cons of aerated compost tea (ACT for short). I’ve been sifting through the peer reviewed literature on the subject. Most of the studies show, at best, mixed results. And, honestly, my bias is against gardening techniques that require gadgets or novel techniques with no analog in nature. I’ve also tried it myself and found that a thick mulch of plain compost seems to work better.

That being said, I want to present a balanced story. I’m interested in hearing from readers about their ACT experiences. Have you tried it? Do you think it works? Or are you skeptical? Leave a comment or send me an email with your name, where you live and whether ACT did or did not work for you. I’d like to gather some anecdotal reports for the story and your help is greatly appreciated.

For those of you not familiar with ACT, here’s a good explanation with some resources via Permaculture Magazine: What is compost tea (and how do you make it)?

On the con side of ACT, horticulturalist Linda Chalker-Scott has a set of pdfs as well as a long list of ACT studies on her gardening myths page.