Unearthed: Secrets of Alcatraz Gardens’ Ribbon-Winning Compost


Alcatraz Historic Gardens

In honor of International Compost Awareness Week, May 7-13, Park E-ventures spoke to Dick Miner, a volunteer at the restored Alcatraz Historic Gardens (a Parks Conservancy program in partnership with the National Park Service), about the island’s award-winning compost.

Miner, who has been volunteering on the island since 2005, is a retired microbiologist living in San Anselmo. On Alcatraz, where he can be found most Wednesdays and Fridays, he has earned the nickname “Chief Composting Officer.”

How did you get interested composting?
I’ve always been a gardener. And as a research microbiologist, I was interested in the science of composting. What I really like is that this is the result of sequential biological processes. It seems simple on [the] front of it, but a rather complex biological process is happening—the result of diverse organisms on the micro and macro level that make everything happen.

Why do you compost on Alcatraz?
Alcatraz’s gardens provided a perfect opportunity for compost to do what it does best. First, compost provides rich materials for gardening, and the soils here, when we started, were exhausted. Second, it is a sustainable way of getting rid of biowaste. You could get overwhelmed hauling away biowaste in dumpsters from an island—especially when the gardens were overgrown.

What do you compost?
99% of our biowaste goes through the compost, including weeds, blackberry, and ivy—things people wouldn’t normally put in compost because of the weed seeds. But our composting is high heat. It runs 130 to 150 degrees, so it kills the seeds and you can safely compost noxious plants. The only thing we don’t compost is eucalyptus. It’s toxic and you don’t want that in your compost.

What are the challenges to composting on the island?
It took a little while to learn how deal with each unique plant that comes through in seasonal cycles each year. Some plants are more difficult than others—they might have long fibrous leaves that you can’t put directly into the pile and there are some things that don’t go through the chipper. Right now, the weed of the day is oxalis. It gets in everything.

What makes Alcatraz compost special?
It’s love! That’s what it is. Every garden is going to have its own unique composition because it is made of the material coming out of your garden. On Alcatraz, there are not that many trees, but there are lots of plant material from pruning and shrubs. So the compost is less woody more green with more nitrogen.

Your compost has won prizes?
I have been entering our compost in the Marin County Fair compost contest for years. We have eight years’ worth of ribbons—a number of blue ribbons and ribbons for best in show.
I do it just because I enjoy doing it, and I know our stuff is pretty good. As a matter of fact, I am making some to enter right now because [the fair] is always in July.

What are the criteria for judging compost?
Color, texture, moisture, smell. You should not see twigs or leaves, and it’s nice to see worms and other critters.

Any tips for composting at home?
Composting really isn’t rocket science. It’s simple, but you do have to pay attention. This is a living thing and an aerobic process. My advice is to try and get high temperatures by using manure. We use chicken manure, and then wet it, and turn it.

What is the most rewarding thing about composting?
The biggest turn-on for me is to put your fork in compost and have it “smoke” [steam]. You want to see steam come out of your pile or put your hand over it and know that you could cook an egg.

But as far as the work on Alcatraz, we are doing a lot more with youth. We have these groups of kids that come out and work in the compost, among other things. I enjoy talking about science with them. I believe if you love something and have a passion for it, people will listen and pick up on that.

You can learn more about the Alcatraz Historic Gardens at alcatrazgardens.org. Tours are available every Friday and Sunday at 9:30 a.m. from the Alcatraz Dock. On Wednesdays, visitors can drop in between 11 am and 2 pm to have questions answered by a volunteer gardener at Officers’ Row.

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