Will using cedar mulch on veggies rob nutrients or have otherwise adverse effects on soil or plants? I can get it cheap and its relatively neat looking in my uban backyard organic garden. I put sheets of newspaper under it around tomatoes, peppers, ets, but where I'm direct-seeding (beans, lettuce) I didn't. thanks.

Redwood and cedar are used for decking and fence posts and even some construction because they are the most decay resistant wood, due to natural tannins that repel mildew, rot and insect damage. Eastern white cedar has a built-in all natural non-toxic preservative. Because of this, cedar needs no pressure treatments. These things are not all that compatible with vegetables which have a short growing season and need nutrients quickly.

Any kind of wood requires nitrogen to break down. Because it is on the soil and we don't inject nitrogen into the root zones of the plants, the nitrogen lands on the wood and starts to break it down instead of getting into the soil where we want it. It takes months, sometimes a year or more to break wood down. Your vegetables will be competing for what they need most this time of year.

If you compost the cedar first with other browns and greens, until it is unrecognizable, you will have good compost, but it will take a lot of time.

Nope. The soil bacteria will not move through that soil/mulch inteface to rapidly digest the woody mulch although they will do that much more slowly. Sometime in the 1970's Organic Gardening Magazine had an article on this and in the current issue of Fine Gardening Lee Reich in his column on "Simply Soil" talks about this issue and says that woody mulches "robbing" the soil of nitrogen is a myth.

I never said anything about soil bacteria. It's no myth that it takes nitrogen to break down wood. If wood is in contact with the soil and the roots of your vegetables are in that same soil, it creates competition. When vegetables have but a few months to produce, the wood which has much greater soil contact is going to win.

Perennials have less of a problem with this because they are established and have a wider ranging root system, but annual vegetables that rely on ideal conditions are at a real disadvantage

But my major concern with redwood and cedar is that they have growth inhibiting chemicals in them, and really should be composted before being added to a vegetable garden

I'm hoping you meant to say the soil bacteria "will" move through the mulch. We'd be in a real pickle if they didn't!

Botton line, cedar mulch is definitely beautiful, but works best on trees and shrubs. Or, you can create a stunning oriental garden with little but stones and cedar mulch if you're so inclined. Serene and simple.

To help veggies, the easiest, cheapest, and most effective mulch is usually grass clippings and leaves.

Many think grass clippings add weed seed, and if your lawn has gone to seed that may be true. But the "weeds" are benign and easy to mulch over.

I've said this for years because unlike the myth it is true that using wood chips or any other high carbon material as a mulch will [u]not[/u] "rob" the soil of nitrogen. Again check Lee Reich's "Simply Soil" column in the current issue of Fine Gardening magazine. He has a pHD in both horticulture and soil science and shoots the idea that high carbon mulches "rob" the soil of nitrogen right down as I have been doing for years.
People posting questions here should be given good, accurate information not myths.

I have never had any problems with wood mulch. If the worms or veggies have been unhappy with it, they have never indicated it to me. I used to read about not using wood chips in veggie/annual beds because it was too slow to break down and created digging difficulties. Mine is gone the next spring so no digging issues. If I plant something later in the season I just push it aside. And I've read too many times to count about tying up nitrogen. I do put in an all-purpose organic fertilizer when I plant - usually about half the recommended amount - and it must be enough to keep the veggies and the bacteria happy.

I have not used cedar or redwood mulch, the fir mulch is much cheaper, so maybe they will not break down as quickly, but I can't imagine they'd need significantly more nitrogen.

I absolutely agree that people should get the real facts about using soil amendments and not misunderstood versions of them.

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Here's what Reich says in Fine Gardening:

"Fact: "Plants are deprived of nitrogen only if wood chips, sawdust or straw are mixed into a soil," but not when you lay them on the surface."

"Soil microorganisms need a balance of their two major foods - nitrogen and carbon - to thrive. When you add a material high in carbon to the soil, the nitrogen to balance it must come from the soil itself. Soil microorganisms are much better at accessing nitrogen than plants are, so plants get "starved for nitrogen." When the the microorganisms die, the nitrogen becomes available again to the plants. The breakdown of material takes place very slowly.

"Problems arise only if a soil is infertile or if seeds are planted directly in a thick layer of mulch."
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1. You haven't said in any of your posts that the wood chip MUST REMAIN ON THE SURFACE. That's the key piece of information that you are leaving out that he includes in his information. Your posts imply across the board that it is a myth that using wood chips in any way, shape or form can create any kind of problem regarding nitrogen as a mulch material. That's not what Reich is saying.

2. It's highly unlikely that wood chips will stay on the surface when people are walking, tilling, hoeing weeds, transplanting, and mowing green manures. At some point large pieces of wood chips will get under the surface, and will COMPETE with annual vegetables for nitrogen, "so plants get starved for nitrogen."

Once the wood is broken down, this isn't an issue, as I have said. Which is why I prefer to compost the wood first, then add it. It just avoids all of this, and it makes a great soil amendment at that point.

3. He does say, "it causes problems if the soil is infertile", and a lot of people at this site asking how to create good soil for a starter garden. He says it can create problems in unamended soil. That's not what your posts say.

4. He also says that problems arise if seeds are planted directly into a thick layer of wood chips. That is a competition issue that wood chips creates.

5. Reich also states in his book WEEDLESS Gardening :
"Add extra fertilizer with nitrogen-poor materials such as sawdust or wood chips"

Not only does he say it does creates some problems, but he says to fix it you need to add fertilizer, which we all know contains nitrogen.

I think it's really important to quote the experts accurately. Reich has made a two-part "fact" about using wood chips, and boths parts are crucial in this circumstance.

Reich is a qualified guy, there's no doubt about it, and he's saying just what the other experts, who are just as qualified, are saying:

University of California, Agriculture and Natural Resources:

"The first year, trees growing with wood chips were stunted. But by the second year, the trees with and without wood chips were growing about even. By the third year, the trees with the wood chips were growing stronger and had significantly more nitrogen. Add nitrogen to offset the tendency for decomposition to make some nitrogen unavailable to the trees at first."

University of Colorado:

"When placed on the soil surface as a mulch, wood/bark chips do not tieup soil nitrogen. However, incorporating wood/bark chips into a soil can create a nitrogen deficiency due to a carbon-to-nitrogen imbalance, and can interfere with seedbed preparation. "

University of New Mexico:

"Wood chips are low in nitrogen, so the fungi and bacteria will take the nitrogen from the soil. Large chunks of wood will decompose slowly. Smaller wood particles with a larger surface area-to-volume ratio will decompose more rapidly. This will cause nitrogen deficiency problems in the soil. If you are using fine shavings or sawdust as mulch or as a soil amendment, you should add additional nitrogen in the form of chemical fertilizer or manure to the soil to provide the needed nitrogen."

I think it's important to not make it a crime, or right or wrong, to use wood chips in one way or another. Some ways may get faster results, some ways may get slower results, but over long periods, and once broken down, wood is a great soil amendment.

You and I don't agree on this issue, but I don't think either of us is wrong. Doing it either way is not going to make or break anyone's garden, no one is in danger of destroying their vegetables, and I think there's room for many ways of doing things.

Wow. Thanks for all the input on this contoversy. hopefully its been clarifying in general.

I was talking about a mulch, not an amendment - so I should be OK (consistent with all.) Of course, some mulch will undoubtedly mix in, but likely not a critical amount (especially where I have the newspaper under it...). Also, I have added compost as well as manure to the soil, so that should help. I'm not planting into the mulch - it's there for mulching purposes only. I didn't have leaves, other more suitable materials etc. in abundance right now - next year for that, and it can decompose in place and help the soil. At the end of this growing season I'll take the cedar off and put it elsewhere, so it doesn't mix in when I re-prepare my garden. Also, I'm not walking, tilling, hoeing weeds, - I've got raised beds, and that's what the mulch is for! I'll be careful to keep it out of the soil - in raised beds (smallish amount) that's possible.

and I've wondered: when you use compost as mulch, don't weeds grow like crazy in it??? It's like great soil, no??

Sweetpea, that was a polished, gracious reply, and I applaud your forbearance.

So-called "hot" compost should have few if any weed seeds in it because they're killed in the cooking. Other compost, like sheet compost, in which you simply cover the ground with organic matter, may have weed seeds, but the benefit of the compost far outweighs any resultant weeding.

The niche of most weeds is dry, barren soil. Compost-rich soil has a wonderful consistency that not only makes weeds easy to cultivate out or pull, but encourages flowers and veggies to take over the bed and crowd out that which you don't want.

Eliot Coleman's book, The New Organic Grower, has great information on this. And some encouraging advice on weeding.

Peter, nice of you to say. I don't appreciate his false accusations of posting incorrect information here, (it's happened before), and yet it is important to step back and realize we are not talking about brain surgery, here. No one's life is at stake.

Zlade, when using anything as a mulch, it's used very thickly, 3-6 inches thick, and weeds or seeds beneath that will be stopped by it. Spent compost is so fabulous you can't help but stir it into the soil or use it in potting soil for seeds. I tend to put about an inch down, then 3 or 4 more inches of leaves and grass clippings and mulch it in place.

The only other element to cedar is that, like redwood, they have those natural preservative chemicals that may slow things down the first year. But as the University of California says, in year 3 things will be better than ever.

Ah, you have looked. This is the kind of discussion from which people learn.