Mulching

 

One year, back when I was a kid on the farm, my dad decided to plant a peach and plum orchard, and my brother and I were given the job of keeping the trees watered. The water had to be pumped by hand and carried in buckets, so you can imagine how much water those trees got! After a long hot summer, only three trees were still alive. One was near the house and got the wash water poured on it; another was next to a concrete slab, and the third one had a bunch of hay piled next to it.

 

My dad, headstrong man that he was, still wanted an orchard and decided to replant. After some strong encouragement with his leather belt to keep the trees watered this time, our creative minds took over. We had noticed that one of the surviving trees was near a haystack under which we always dug to find fishing worms-worms that thrive in a moist atmosphere. Maybe piling hay around the trees would help keep the ground moist. We talked Dad into helping us (or rather, we helped him), and this time-success!! Even with little watering, the orchard survived.

 

Through the ages, trees have been shedding their leaves, and the smaller plants and grasses have been dying and falling to the earth, providing a natural, protective mulch cover.

 

With a little study, we can understand how this mulch protects the soil from erosion, sunbaking, and crust-formation which prevent water from soaking in. A mulch of leaves and grass on the soil helps prevent heavy rains from rushing off to the creeks and rivers, swelling them into swift, destructive muddy torrents. We can also see how this organic blanket holds the moisture in the soil for plant use and keeps the soil temperature cool in the hot summers and warm in the cold winters.

 

With the scratch of a finger, we find the earthworm feeding in the moist rich layer of decomposing mulch next to the soil. With the aid of earthworms and many smaller soil organisms, such as bacteria, algae, fungi, etc., the decay of mulch is completing the cycle of life by turning the mulch into humus and feeding a new generation of plants all the life-sustaining nutrients that were in its tissues-tissues which came from the preceding generations of plants.

 

When we walk on the mulch-covered earth, our feet don't get muddy and the soil doesn't pack. Mulches around trees and plants also enhance the beauty of landscaping and help in controlling weeds, These are some of the obvious and easily understood benefits of mulch. But mulches provide many more unseen and not so well understood benefits.

 

Because the surface soil packs to a crust and reaches extreme temperatures, plant roots usually do not use the top inch or two of soil. With a mulch cover, the roots come up even into the mulch itself, and the root zone of the plant increases. The soil surface right under the mulch is the most fertile.

 

The greatest benefit of an organic mulch on the soil is derived from the activity of the decomposing microorganisms and the products they form. Growth-promoting hormones and certain toxins and antibiotics that don't harm plants are formed, and these help to control diseases, root rot, and damping off fungi.

 

A decaying mulch of bark, leaves, grass, etc., promotes the growth of a mycorrhizal fungus that envelopes plant roots with a mycelium, absorbing nutrients from the soil and even directly from decaying organic matter and passing them on to the plant roots. This mycorrhizal association is very beneficial to trees. In the tropical forest, trees couldn't grow without it. Another beneficial fungus, one that traps and destroys root-knot nematodes, also grows in the decomposing organic matter. During the decomposition of organic materials, the microorganisms secrete a sticky substance which glues the soil into little crumbs, promoting good soil granulation, and thus, better soil structure.

 

In general, mulching improves the health, and can even increase the life-span of trees and plants. Some even claim that mulches improve the flavor of fruit!

 

After reading about all the near miracles mulches perform, I'm sure you will want to mulch your plants and trees and wonder which is the best to use. Compost, a mixture of many types of partially decayed organic materials including manures, is the best mulch. A thin layer of compost under native tree trimmings is the ideal mulching combination. You duplicate the forest floor this way and have a rich source of nutrients. Corncobs are next. Many other organic materials, including leaves, hay, grass clippings, seed hulls, etc., make good mulches. Let availability of material dictate which one you use. However, any that could contain weed seeds, nematodes, or diseases should first be well composted through a heat cycle. When mulching with high carbon-low nitrogen materials such as sawdust and wood chips, extra nitrogen should be added to offset the temporary nitrogen tie-up caused by the decaying organisms.

 

Three inches of mulch is desirable, but anything from one to six inches is all right. Depth of the mulch depends on the size of the plant and material used. A fluffy straw mulch would naturally be used thicker.

When mulching established trees, start a foot from the trunk and mulch out to a foot or more beyond the drip line of the canopy. Lawns should be mulched with a 1/2-inch layer of compost in the fall. Mulching with compost, rather than adding more soil, makes the lawn fluffy. The grass receives less damage when walked on, and the yard doesn't rise above the walkways and house foundation as when dirt is added each year.

Some inorganic materials can also be used for mulching:

1.  Dark plastic film is used to warm the soil extra early in the spring, allowing a jump on the season with vegetables. It also controls weeds well and holds moisture, but it causes the soil to overheat in the summer, and it feeds no organic matter into the soil. The water it sheds can cause erosion in nearby soil during heavy rains.

2.  Aluminum foil controls weeds and holds moisture, but is used primarily to reflect light back onto leaves for greater photosynthesis. Overheating and lack of organic matter are the drawbacks to using foil as a mulch.

3.   Gravel (or stone), one of the better inorganic mulches, is beneficial for (a) using around trees to give them greater anchorage against strong winds,  (b) stopping weed growth, (c) conserving moisture, (d) moderating daily temperature fluctuations, (e) absorbing heat during the day and releasing it at night, which could provide protection for buds and blossoms directly above the stones on frosty nights, (f) discouraging mice and other animals from burrowing, digging, and scratching soil away from the roots and trunks, and (g) providing, as they weather, calcium, magnesium, etc., depending on the rock composition, for the mulched plants.

The drawbacks of mulching are very few:

1. A heavy mulch around certain plants during extreme wet seasons can hold too much moisture.

2. Covering the soil with organic mulch around vegetables too early in the season can hold them back by keeping the soil too cool. However, this same effect could be beneficial to certain deciduous plants and fruit trees that you want to have a longer dormant period.

Though initially mulching seems to be a lot of work, in the long haul, it actually saves work by reducing the amount of weed hoeing and vegetable washing required for clean produce.

The benefits of mulching far outweigh the drawbacks. After all, how could we go wrong by following one of Mother Nature's programs that has been proven to work throughout the ages?

 

Benefits of organic mulch on the soil:

1. Increases root zone

2. Maintains even soil temperature

3. Conserves moisture

4. Prevents crusting-increasing in-soak and aeration

5. Stops erosion

6. Controls weeds, eliminates cultivating

7. Keeps heavy rain drops from splashing soil on lower leaves

8. Provides walkways-your feet don't get muddy

9. Increases the number and activity of the beneficial soil life (earthworms and microorganisms)

10. All the benefits of tilling organic matter into the soil

 

Benefits of organic matter in the top four inches of soil:

1. Growth-promoting hormones

2. Toxins and antibiotics

3. Mycorrhizae fungi

4. Nematode destroying fungi

5. Sticky substances

6. Unlocks minerals

7. Nitrogen-fixing microorganisms

8. Increases moisture-holding capacity

9. Increases air space-drainage and aeration

10. Acts as a buffer against chemicals and high/low soil pH

11. Maintains the soil base exchange capacity

12. Releases nutrients over a long period of time

13. Gives soil good tilth--easy to work and till, wet or dry

14. Recycles waste products and prevents erosion

 

The Garden-Ville Method - Lessons in Nature