Umbra on composting weeds 0

Dear Umbra,

I've been weeding the garden and yard, and got to thinking about some of the more invasive plants. I've heard that not everything goes in the compost pile, but what weeds can I toss in? I'm fairly new to the composting game, so any advice is much appreciated.

Danielle Walker
Monroe, Ore.

Dearest Danielle,

Composting is the original and highest form of recycling. People frequently write in to ask what can go into their recycling bins. While recycling is specific to the services available where one lives, composting is a do-it-yourself endeavor, and there are some universal rules a beginner can follow. (Ye recyclers, I take this opportunity to point out, should not be asking me about what you can recycle. Ask the people who sponsor your recycling program -- usually your municipality.)

One good turn deserves another.

Photo: iStockphoto.

What you can put in to your compost pile depends a little on your method. An active composting fanatic who builds the perfectly mixed carbon/nitrogen ratio pile and turns it every three days for three weeks, ensuring temperatures above 120 degrees at the middle of the pile, can be adventurous with ingredients. However, if you are a laissez-faire composter, your pile is simply a mound of weeds left to its own devices, and you intend to put it back on the garden, then you should follow fairly strict guidelines.

Your pile cannot kill any truly determined plant. The broad rule is, don't compost any plant bit that you don't want to see again. For example, if you decide calendula is a weed, the leaves, stems, and flowers are probably not going to give you any trouble; it's the seeds that will be a problem. So, catch weeds before they go to seed, because the seeds will simply go dormant in the pile and await their next opportunity to sprout -- in your garden.

You have weeds in your area that spread through their roots or rhizomes. Mint, for example, or blackberry, or witch grass. These plants are easily recognizable: as you pull them out, a long evil chain of white root comes with them. Don't put these in the compost. They can take it over like a scourge.

Don't put in anything with thorns, which will poke you later; nothing shiny and hard like fir needles or laurel leaves, which take forever to break down; no bark mulch or big chunks of wood. No food unless you live in the country and aren't bothered by raccoons and rats digging through your pile.

Lastly, nothing diseased. Your pile will not kill all pathogens.

To move from compost beginner to advanced composter, trot over to the library and get a book from Rodale Press. Or start on the web with handy pages such as this one from Ohio State University Extension.

If you do have quite a bit of space and don't want to pay to dispose of invasive plants, think about making a wild pile in the back 40. A corner of your land where you can chuck the rose prunings and blackberries and field bindweed, and they can duke it out amongst themselves for world domination.

Thornily,
Umbra

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