Why Mulch?

Organic gardeners hear over and over:  Mulch, mulch, mulch.  We know it saves water, but what if you have plenty of water?   We know it is helpful to microbial life, but what if you’ve got plenty of compost mixed into the soil?  We know it insulates plants from heat and cold, but what if you garden in a mild climate?  Let’s have a good look at mulch.

Water management, in the soil, is often overlooked by even experienced gardeners.  Plants in dry soil are unable to access water – this is pretty obvious to gardeners.  But, what happens on the other end of the spectrum?  When we pour water on the soil it becomes saturated.  In the case of soils with too much coarse particulate, the water may not linger long enough, for the soil to become completely saturated.  The average soil will run between saturated and water logged.  Very healthy soil will hold the flow of water long enough to absorb an optimal amount and allow the excess to drain off in a timely manner.

Why?  Because, healthy soil is being carefully managed by a huge community of micro and macro organisms.  They create the particles and pathways that facilitate their own movement, and create that not too fast, not too slow drainage that help plants thrive.  But, like a drowning man, plants cannot benefit from water when they are flooded.  In order for roots to absorb water, they must also have air.  So, when we water our gardens, plants must wait until the air pockets return to use the water.  Since mulch slows evaporation, keeping soil moist long after it drains, plants enjoy a longer period of time to spend with ample water AND necessary air.  The ideal water cycle looks like a bell curve:  It starts with too much water,  makes a long climb to the sweet spot, begins a slow decent and only then approaches the too dry, bottom of the bell.  If you have a good layer of mulch on the soil, you will have a longer window of time, to water and start that cycle over again.

Beneficial soil life is dependent upon moisture.  We can see what happens to an earthworm when it dries out.  What we don’t see is the huge population, of smaller soil life, that dies or goes dormant when water is unavailable.  This community creates the supply lines that nourish your plants.  When the top layer of soil gets dehydrated that community is hobbled.  Even if the soil contains plenty of organic material, that living compost will become dry dirt in short order, even if the soil below is soggy.  The same soil and compost, under a layer of mulch, stays moist and active.  The supply lines are constantly delivering nutrients to the plants and have unlimited access to organic material, as they break down the mulch.  Organic gardeners grow soil.  And, this is how soil is created in nature.

I recently observed a sudden temperature drop of 60 degrees, in less than a day.  I didn’t like it much, but the plants really hated it!  Extreme conditions in the environment are no friend to plants and will shock them.  But, whether you are dealing with heat or cold, soil conditions are moderated by mulch and the community beneath it.  Many extreme weather events are accompanied by high winds.  Unprotected soil blows away.  Exposed, dessicated roots die.  And, plants are shocked even more.  A nice cozy layer of mulch won’t eliminate all the effects of insane weather, but it can give assistance in managing it.

All of these benefits, offered by spending the time and effort to apply mulch to your garden, are well worth it.  If you are fortunate enough to live near a forest, go out there and take a peak under the leaf litter.  You will see mulch and compost perfectly done – so perfect, in fact, that it will be hard to tell where the mulch ends, where the compost is and where the soil begins.  Nature is full of grace.  Copy her.