Mulch!

It’s been a long time since our last post. We’ve been busy, but mainly we've just been lazy bloggers.

Mulch has changed my life.

A little exaggeration there, but mulch HAS changed the face of Terribly Happy, and helped fortify our trees, shrubs, and other plantings.

Mulch is placed atop soil to provide one or more of the following benefits:
* slows soil evaporation, so less irrigation is needed
* insulates soil, so soil temperature doesn’t change as much and doesn’t freeze or cook as easily
* provides raw materials for decomposers (worms, etc.) to generate future soil
* inhibits weeds, and may make pulling weeds easier
* minimizes yard waste

Secondary, but significant, benefits accrue directly to the orchardist or gardener (e.g., me): less time and money spent on irrigation, weeding, frost protection, etc., and thus lower overall stress levels. For example, in 2013 this part of Oregon had its driest January-May on record, yet I didn’t start irrigating until late June because mulches kept the soil cool and moist.

Mulch has to be able to transmit air and water, so solid plastic sheeting doesn't qualify. Lots of other things do, though; here's a semi-complete list of mulches we've used recently with information about sources, collection, and other stuff.

Grass cuttings

Source: orchard, other grassy areas of property

Collection: ugh. raked piles (no collecting bag on the mower, yet), wheelbarrow as needed

Available: Mainly Apr, May, maybe June; key springtime mulch


Top: Grass ring w/Sherlock

Bottom: several small trees w/mulch rings (walnut in foreground)








Chop-and-drop cover crops

Source: warm-season (buckwheat) and
cool-season (rye/vetch/fava mix) crops
that I planted and scythed down. No
tilling--they just decompose in place.

In this photo, I haven't yet moved the
cuttings to the mulch rings around the
key plants.








Other organic matter (no pictures): weeds and plant trimmings: thistles, dandelions, grape vines, comfrey (planted mainly for this use), tree suckers/water sprouts, etc. The few types that re-root (damn bindweed) go the dump or are burned.

Leaves

Source: Mainly the oak trees from the neighbors across the street. Sometimes they pick up and dump piles for me, but usually I go over with a rake and an old sheet and drag them home!

As time goes by, our trees will mature and we'll have an increasing supply of our own leaves.

Top: Thin leaf pile around a baby chestnuts; needs a lot more mulch.

Bottom: Sheet mulching w/leaves

Straw

Source: purchased bales; too pricey to do this regularly unless purchased in bulk (as I did for the pictured project).

Be sure to get straw and not hay, which is seed-filled.

Sawdust and peat moss

These materials aren't good for all plants, but blueberries love them.

The sawdust came from a local, small-scale mill.

The peat moss was purchased at a nursery.

Chopped cypress foliage

Source: A cypress on the property that we felled because it was growing like a weed....a 25-foot-tall weed that blocked our view from the back deck.

I painstakingly trimmed off all the foliage with pruners.


Grape pomace

Stems, skins, and seeds hauled in from a local winery (11 tons!) Half was used in compost, and half was used in a sheet-mulching project. We didn't expect the long-term viability of grape seeds. Fortunately, young grape plants are easy to pull out.

Top: Pomace close-up.
Bottom: Sheet-mulching project underway; grape pomace partly covered by straw in foreground.










Horse manure (no picture): An adjacent neighbor supplies us with horse manure (dung + straw) periodically. We store it in the barn for a year to let it dry out, then use it in the compost pile or as a mulch. When used as a mulch we cover it with other mulch types to deter scavengers.

Newspaper and cardboard

These decompose within about six months (of wet weather), interfering with most weeds and giving new plantings a head start.

Top: Part of a sheet-mulching project (later covered with bark mulch)

Middle: Torn-up cardboard that I covered with straw and grass, and into which I then hand-sowed buckwheat.

Bottom: Newspaper & cardboard as part of sheet-mulching.

 

Pea gravel, bark mulch, wood chips from a local materials yard.

Decomposition rates range from slow to zero (pea gravel), but each has its uses.

Pea gravel is especially easy to work with and weed, and discourages field mice who might munch on a young tree trunk.

Finally, weed fabric is an effective weed deterrent. I used it on fairly mature apple and hazelnut trees in the orchard, and my weeding time on those 60 trees is now negligible. Not sure whether I would ever do it again, though. It transmits air and water, but prevents the development of any kind of organic matter.

Recommendations: Construct mulch rings around any tree or shrub that matters to you. The radius of the ring depends on the size of the plant and availability of mulch (I'd have made my rings thicker if I had more mulch). Maintain a thickness of at least 4” (most of my mulches are 5-8” thick); how quickly your mulch decomposes depends on temperature and precipitation. If you have to irrigate, do so under the mulch (w/drip, hose, etc) to help slow mulch decomposition. Most guides specify a mulch-free zone around the trunk to avoid disease, but in cold winters it’s probably better to pile the mulch around the trunk and then move it away as the weather warms.

You'll find plenty of "mulch advice" in online articles and forums. Good luck!