The Gordon Gnohm

Play along at home, read Future Farmer in The Braidwood Bugle every Wednesday. 

Mulch Pt 1

Mulch plays a critical role in every ecosystem on earth. It comes in many forms, but the same thing happens where the mulch touches the surface of the soil. Theres a party going on for the roots of your plants. 

Mulch is the protective layer over your precious soil and it’s also food for hungry microbes.

If you aren’t using mulch you are growing in dirt, not soil.

Soil is Alive. Dirt is Dead

Microbes are amazing! They boom when there is food available and bust when it is gone. If you can keep a core population alive in your soil, they will wait for the next dressing and boom to process the fresh material. 

Adding compost to boost your soil is the organic way, but if you don’t have mulch, there is no hope of keeping it alive. If you forget to mulch or refuse to mulch, your soil will turn to dirt in front of your eyes because compost is not really a mulch.

Compost is a living system, full of beneficial microbes. Once you spread it on top of your ground, the compost is under threat from the sun. The quickest way to destroy life in your soil is to bake it in the sun. The suns harsh rays evaporate the water out of the soil and with it all microbe life. Soil to dirt.

It is a practice you can see in paddocks everywhere. Plow or till, then let the soil bake in the sun until it becomes dirt. Its microbe genocide.

Microbe habitat is moist, warm and protected from direct sunlight in a compost heap. When you apply compost in a thin layer you are literally laying the microbes out to die. If the compost is turned into the topsoil mechanically, all the hard work the microbes have done to build structure in the compost will be destroyed and they will die. 

This is all pretty grewsome, but it is how humans have done things in the past. As we evolve our understanding, we can learn to create ecosystems and let the soil grow. Water and microbes will maintain a healthy ecosystem in your soil if you give them half a chance.

Mulches fit into 5 categories;

  • Feeder Mulch
  • Decorative Mulch
  • Protective Mulch 
  • Mulch to Avoid
  • Living Mulch

Feeder Mulch

Feeder mulches are the most important mulch in your garden but if used incorrectly they will not provide any feeding to the soil. A feeder mulch provides building blocks for your microbes to convert. Each mulch has different benefits. Feeder mulches work best with toppings of active compost or worm castings as weve learnt previously.

Lucerne & Pea Straw are common feeder mulches. These mulches are best for vegetables and berries. If laid directly on top of the soil, in the sun, the surface of the mulch will dry out repelling water to the edges of your garden beds. No water, no microbes

Woody Mulch is a common feeder mulch for trees and shrubs as Fungi prefer wood to convert into nutrients. 

Have you ever noticed that a gum tree is always shedding limbs, widow makers they call them. Its not that gums are crappy trees, infact it is the opposite. Gums are masters at self mulching. In the dry harsh climate of Australia, Gums drop limbs that break down over decades, decomposing into topsoil. The problem is most humans don’t like the limbs laying around so they rake the mulch up or they burn it. 

Both these approaches remove mulch from under gums, baking the earth and reducing the ability for the dirt to hold water. Clearing the dropped limbs actually triggers the tree to drop more limbs. Tree stress is caused because of the lack of woody mulch underneath and/or competition from grasses. Dropping limbs over centuries has resulted in some pretty amazing ecosystem’s, just check out Monga National Park. The mulch on the ground there is eons deep and the nutrient load is off the charts. Make your landscape more like Monga.

Trees that drop leaves have also created amazing ecosystems. Check out 7 mile beach at Gerringong. It starts with salty sand at the seas edge. Grasses grow to hold the dunes together creating habitat for bansksia. The banksia leaves are the primary materials mixed with the sand to start creating soil. This carries on all the way back to the escarpment. The system gathers different mulch materials and becomes more complex, eventually climaxing in the temperate rainforests.

Deciduous trees drop mulch every autumn creating a mass of deep leaf litter. If left alone this litter will decompose and become soil. But most people rake it up and send it away to be processed into mulch. Then they buy it back.

Kunzea, Tea Tree and Casuarinas drop fine leaves everyday creating a thick mulch on top of their roots feeding the microbes and preventing water loss. This mulch makes way for more species of plants and higher forms of nitrogen, so weeds cant grow. 

Imagine for a moment if you could assemble these mulch droppers around your property or garden. Imagine the soil that could be created if we left the materials where they fell. I like to design these kinds of areas into gardens and paddocks, to create mulch sinks for added nutrients with zero effort by humans. Put this kind of arrangement on a hill and gravity will share the wealth around.

Past programs planted out hilltops with natives for habitat. The trickle down would carry nutrients into the paddocks slowly over a very long time. But where are the nutrient coming from in these plantings. Because if there is no mulch, there is no microbe action. 

Imagine if these patches were replanted with a mix of the mentioned trees and shrubs to create deep mulch in that space. The trickle down effect will be readily visible as the grass below becomes lush green regardless of the climate cycle.

This week

The first cicadas are singing in the garden and its only September. Summer sounds at the start of spring is alarming. Happy Summer?

Potatoes are starting to pop through the mulch. The first Caulis are finally in flower. Tomatoes have been hit by 3 light frosts now. -1 doesn’t seem to be a problem for them. And as im editing its HAiling!

Bombay Seed Traders are doing a great job delivering hardy vegetable seedlings. No greenhouse has translated into very strong tomatoes. Since they were planted almost 2 weeks ago, they have doubled in size and flowers are just starting to form, which means December tomatoes! I missed some night boxing, cause the weatherbots cant be trusted, but they survived the frost. Chicken breakins have been worse than the frosts.

Pumpkins go in the ground this week as my soil temp climbs past 19C. Ill try zucchinis and cucumbers too. These guys are not frost hardy, so itll be risky putting them in, but the growth ill get in the next week will be worth it if they survive. Night Boxes at the ready.  

Next week Mulch part 2

Happy Summer

The Gordon Gnohm

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