Monday, November 1, 2010

Can't stop the rain, but a good layer of mulch helps

A windy night followed by a rainy day.  Thus we have a typical start to November on the Oregon coast.

As we move into late fall, most of the usual season-ending chores are completed.  The vegetables harvested, the leaves mostly (if not all) picked up, patio furniture cleaned and stored in a dry place.  But have you mulched?

One of the most critical and commonly overlooked tasks is soil protection.  On the central coast of Oregon we not only receive our share of high winds throughout winter, but (not surprisingly) the majority of our annual rainfall.  It doesn't often arrive in a gentle mist but instead with firehose-like force.  Sometimes the rain seems to fall here unrelated to gravity; rather it appears to be driven out of the sky and pounded into the earth.

Studied gardeners know that keeping planting beds free of foot traffic is good practice for avoiding compaction. Compaction is the enemy to thriving plant roots, as the air (pore) spaces are eliminated.  When this happens, not only is it difficult for the roots to expand and grow deeper, but they have a tough time accessing water and nutrients, not to mention necessary oxygen.  Yes, those roots need to breathe!

Heavy rainfall compacts soil just as surely as our heavy tracks, not to mention displacing much of your carefully managed topsoil down the street gutters and into our storm drains.  A good layer of mulch on exposed soil will do wonders to mitigate both issues and protect your soil.

Mulch can be as simple as a 2 or 3-inch layer of barkdust or "beauty bark"-- although our public works department is encouraging use of the more chunky bark pebble or the rough material known as "hog fuel."  Hog fuel is often free from tree services, the mixed roughly cut product of their branch chipper.  Bark dust is apparently causing increased maintenance of storm drains due to the very fine dust that is flushed away.

Another great free mulch option is to place a thin layer of your lawn clippings (1-2") on bare soil areas, provided it's not full of weed seeds.  Straw is easy to come by in the fall from valley farmers, usually wheat or oat straw, and sometimes "grass" straw from the grass-seed fields.  I prefer oat straw, and place a nice layer over my veggie garden beds with cover crop seed sown underneath.

Unique to the Willamette valley is the option of hazelnut (filbert) shells from area farms, which make a semi-permanent mulch that is quite effective at preventing weeds.  A very permanent mulch option is the variety of rock materials we have here, from round river-type rock to lava rock (somewhat out of place here) to locally sourced beach rocks/shells and even commercially harvested and crushed oyster shell.  These materials can be a nice option for paths or permanently planted beds, especially next to gutters and downspouts where the rock will minimize mud-splash onto adjacent buildings.

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