Question
QUESTION: Frank and Vicky:
I have large areas of plants and shrubs. Over the years I have used a mulch which has been treated with iron oxide. This year I used a cedar mulch. But the cost of mulching each year and the amount of work required to mulch large areas, is not winning the war against excessive weeds. My question is this: is it desirable to spread a layer of mulch (of any variety) over the leaves that have fallen  in the garden areas. It seems to make sense to me. The leaves would act as a barrier to weed germination and the layer of mulch over the leaves would add beauty. Would you recommend that strategy.
Thanks for volunteering.

ANSWER: The best mulch is to get a bale of alfalfa hay, and break it apart and mulch with it.  You can just put it right over the leaves. When it breaks down it adds nitrogen to the soil, and worms love it.  Cedar is actually toxic to plants.  If you use a good 4 inches of alfalfa there will be no weeds.  If you could rent a shredder for a day and grind it up with some composted chicken manure, you would really have the best possible mulch which would also feed your soil and plants.  The secret is to have it thick enough that weeds won't make it through, and if they do they pull out really easily.

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QUESTION: Frank and Vicky:
Many thanks for your very quick and veryu informative response.
I have about 2 inches of non-cedar mulch and about 2 inches of cedar mulch on top of that.
Is there any way to detoxify the affect of the cedar mulch on my plants.

ANSWER: You could try to take the cedar layer off and get rid of it, or you could just add a four inches of alfalfa mulch and mix it all together in place...that would minimize the effects....I think I would try to remove it and put it somewhere that I wanted nothing to grow.

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QUESTION: Frank and Vicky:
You indicated that Ceadr Mulch is toxic to plants. Now I am concerned about its use in my vegetable and herb garden. Does that mean that cedar mulch should not be used in vegetable gardens. What is the nature of the toxicity. Is it an unsafe chemical that can get into vegetable plants. Or does the cedar mulch simply mess up Ph levels in the soil. I hope it is the latter.

Answer
You can find opinions either way about the toxicity of cedar mulch.  Our experience comes from the northwest, where we had western red cedar, and it contains a substance called Thujone, and we noticed that nothing whatsoever grew under these trees.  We used it as a weed barrier around the edge of our gardens (two acres) and nothing grew there. There are no official studies as to whether or not it is toxic to plants, but there are some studies that indicate cedar bedding should not be used for pet gerbils and mice. In our experience, we have had trouble with germination when we tried mulching with it. As far as pH, it might increase it a tiny bit, but that would not be a concern if you are testing your soil and adding nutrients. I still would not use it as a mulch, especially in an organic vegetable garden, when so many other alternatives are available. For more information on soil building and mulching, please visit our website:  www.avant-gardening.com