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Thursday - November 04, 2010

From: Austin, TX
Region: Southwest
Topic: Compost and Mulch, Soils, Trees
Title: Do leaves with tannins make good compost from Austin
Answered by: Barbara Medford


I have a couple of old native pecan trees in my (or neighbor's) yard that drop bushels and bushels of leaves every fall. Somewhere in the back of my mind, I have a recollection that pecan leaves have too much tannin (or something else) to make good compost. Was I dreaming? Now that I am composting everything I can lay my hands on, should I throw the pecan leaves in the pile? Thanks!


First, congratulations on your composting practices; nothing is better for the environment, in our opinion. Second, there are always arguments about what is okay to compost and what is not. We found this comment from an article by Neil Sperry for the Wichita Falls, TX Times Record News:

"Leaves of oaks, pecans and walnuts all contain tannins, and there are always those out there who contend that you should not include any of these in your compost piles or in your garden soils. Let me answer from my personal experiences. I grew up in College Station, where I used post oak humus as my main source of organic matter in my gardens and greenhouse soils. It was naturally composted beyond recognition of its origin, so the tannins were of absolutely no concern. For the past 32 years, I have lived and gardened at the floor of a pecan forest, and I’m knee-deep in pecan leaves every fall. I run them through the mower, compost them, and proudly use them without any repercussions at all. Two pieces of advice: Use your mower to speed the composting along, and include other forms of organic matter in your compost pile. Decaying manure, grass clippings, “scalpings” from your first lawn mowing of the spring, etc. A combination of several forms of organic matter is always a better idea than having only one."

The message here is compost early and often and long enough to do the job. The organic matter mentioned in the excerpt contribute nitrogen and help in the "heating up" part of composting. If you don't have enough "green" material, you can buy a bag of cottonseed or alfalfa meal at the feed store, and layer your leaves with that, remembering to moisten the pile and keep turning it. By all means, don't waste those leaves!


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