About 4 years ago, I put down 4 inch deep of wood chip mulch (cheapest kind bought at Home Depot), and then 1 inch every year after. I noticed lately, grass and weed have been growing much more than before. I suspect that the 4 inch of mulch is now only 2 inch, since the lower 2 inch had turned to soil. Even though it look like the same height as before.

What method of mulch management is better? Do I need to dig deeper and remove soil every so many years?

Residence: S. California. Zone 9.

  • This somehow depends of the part of the world you live in, and the size of your wood chips. And what do you want to do with your "soil"? please edit your question to be more accurate.
    – J. Chomel
    Commented Apr 26, 2017 at 9:40
  • 1
    Please add a photo or two - what was there 4 years ago may have rotted down, but weed seeds can grow quite happily by blowing onto the mulch and germinating rather than coming up through the mulch.
    – Bamboo
    Commented Apr 26, 2017 at 14:56
  • As it rots down, it will also reduce in volume. Compaction also lowers the level. You may need to clear around some plants but I can't say I've noticed much increase in soil level after 10 years with bark mulch (new soil at that time so I'd get more comaction than some people)
    – Chris H
    Commented Apr 28, 2017 at 12:20

1 Answer 1


A geotextile would be better- although you will have to cover it with something like a bark mulch, stones or what ever pleases you.(only a weed barrier not a light barrier- as weeds need light to grow) In traditional old world gardening (Classical Horticulture) we where taught that Victorians if they added horse manure to soil, that every few years they had remove a layer of top soil from the flower beds to stop them from getting to high- I can't remember what the practice was called... but its considered a very drastic choice since any form of mulch improves the soil underneath. Either that grow something that's very hungry and requires a lot of pruning thus using up the material/nutrients from the mulch and removing material/biomass in the form of green material from your garden eg. woody plants for burners, vege, cut flowers. hope it helps.

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