Wood Chip Mulch

[Durgan]

http://www.durgan.org/URL/?DQFDJ 14 September 2009 Wood Chip Mulch
Over the last three years, I have become an advocate of mulch on all my garden beds. This wood mulch is supplied by the city available in one of the parks. It varies a bit in texture depending when one picks it up.

In my case the soil about two feet down is hard packed material,which is almost impenetrable, so there is no wick effect from ground table water. All my moisture comes from overhead water or rain if you like, so drying out is often encountered.The mulch disintegrates rather quickly, and I am constantly adding a new layer. This no doubt improves the soil to a large degree.

The mulch inhibits evaporation and enhances growth considerably,hence little extra watering is necessary. I have four 45 gallon drums to collect rainwater and utilize this in extreme dry conditions, but avoid watering as much as possible.

[dave45]

Does the regular addition of this woody material adversely affect the soil balance? e.g. too much carbony stuff, not enough nitrogen? if so what is this good news for, and what is it bad news for?

[Durgan]

Does the regular addition of this woody material adversely affect the soil balance? e.g. too much carbony stuff, not enough nitrogen? if so what is this good news for, and what is it bad news for?

When working into the underlying soil, I spread a bit of Urea (N) as insurance due to caveats in the literature. I have found no evidence of nitrogen depletion in my plants. The chips disappear in about six months and I am constantly adding a new supply. Actually the chips are often partially composted, when I pick them up.

[grahamhobbs]

Woodchip can rob nitrogen from the soil, at least in theory, but will also make the soil more acid. Neither of these in practice are serious and are easily rectified. Another problem I've found is that if you need to dig the soil for any reason, eg. to dig out pernicious weed roots, then a lot of unrotted woodchips get incorporated into the soil, where they will takes years to rot down. Not sure how much of a problem this is, although I think the nitrogen robbing and acidification will be increased. If I had a choice I would atack the chips and allow them to rot down a bit before using them.

[boboff]

It's only in the initial stages of rotting down the the nitrogen is robbed, after this stage it gives it back I think.

[Durgan]

There appears to be no obvious deleterious effects of the wood chip use. The primary use is to inhibit moisture loss due to evaporation from the hot sun. I have no scruples about working the chips into the soil.

Truly, I am amazed to not find one chip in the garden after a season or slightly longer.The chips are relatively small and often partially composted, when applied. The supply pile is often very hot due to compost activity.

[GrowingVeg]

Quick Tip: Get to know a local tree surgeon or council worker and get this stuff very cheap or free !