Mulch provides many benefits to plants and soil:
insulation, shade, moisture retention, weed reduction, and
soil building. But when mulch is applied at the wrong time
or in the wrong form, it can do more harm than good. Use
the following guidelines to get the greatest benefit from
your mulching effort.

First, make the most of your garden space, moisture, and
organic matter (including mulch) by planting wide rows - a
width that you can comfortably reach across, rather the
width of a single plant. Wide row planting reduces the
number of paths needed through your garden, and keeps more
of the soil surface covered. This results in fewer weeds
and better moisture retention, so your mulch can be applied
where it is really needed.

~~Finished Compost Mulch~~
There is no bad time to add finished compost to the soil,
but for maximum value from this black gold the best time is
shortly after spring shoots and seedlings have gotten
established and have their true leaves. Apply a layer of
finished compost mulch. Often called a top dressing, this
layer will merge with the topsoil quickly, but try to keep
the compost from touching the plant stems anyway.

How thickly you layer the finished compost mulch depends
on how much you have available and how much ground you have
to cover. Even a thin layer is beneficial; it provides
nutrients that gradually work their way down, and gives
some protection against weeds, temperature extremes, hard
rain, and so forth.

~~Partially Composted Material~~
Half-finished compost or compost that is noticeably
fibrous is never good for mulching plants, or even for
adding to the soil near growing plants. Separate additions
of partially composted material from planting by at least
two or three weeks. The best time to add this kind of
compost is in October or November in ground that will be
allowed to rest.

Soil bacteria will break down the material, but these
organisms have to use nitrogen in order to do their work.
Eventually, the microbes will release the nitrogen and make
it available to plants again, but in the meantime, the half-
finished compost has the effect of starving rather than
feeding any growing plants.

~~Hay and Straw~~
Apply a layer of straw or hay once plants are beyond
seedling stage. The timing also depends on soil
temperature. Since this mulch forms an insulating layer,
wait until the soil is warm; else the layer of mulch will
insulate in the wrong way-preventing the soil from warming
up.

In addition to the straw or hay forming an insulating
layer and helping retain moisture, the mulch becomes a nice
resting place for melons and squash.

Straw is more carbonaceous than hay, and will break down
more slowly. Hay often has a moisture content, and will
break down faster. Both are good mulches, but if slugs and
snails are a problem, straw is better. Again, keep the
mulch back from touching the plant stems.

~~Leaves and Grass Clippings~~
I prefer to compost leaves and grass rather than use them
as mulch. Leaves are generally acidic, and affect the ph of
the soil. However, some plants such as raspberries prefer
slightly acidic soil, and for plants that don't like an
acid ph, an amendment of lime could help neutralize the
effect of the leaves.

Grass clippings can be very effective mulch - especially
for moisture retention, but keep an eye on it. Grass packs
down, preventing air circulation so that anaerobic decay
occurs. Again, I prefer to compost grass; turning the
compost keeps it aerated.  

About the author:
Life-time gardener Judith Schwader specializes in organic
gardening methods. She shares expertise, humor, and advice
for your gardening success at A to Z Gardening. Also visit
FB Home for additional home and garden information.