Plants Need Probiotics Too!

May 28, 2014

Similar to our own digestive systems, plants need many beneficial microorganisms to be healthy.

Think about burrowing down under the rich, fertile earth, like an earthworm perhaps. The cool humus holds you close, and provides everything you need to thrive, including different bacteria, fungi, plants, minerals, moisture, and nutrients. This is the best-case scenario for our little friend. No pesticides, herbicides or other chemical or physical disturbances. The soil in a healthy ecosystem has over 30,000 taxonomic varieties of microorganisms. Two of the most important classifications for plants include bacteria and fungi. Plants rely on a vast array of bacteria and fungi for both health and defense. These relationships are symbiotic, meaning that they benefit both the plants and the microorganisms.

Bacteria:

Bacteria in the soil not only provide nutrients for plants but also suppress disease. In exchange, plant roots secrete fixed carbon into the soil and feed their bacterial counterparts. Soil bacteria can trigger defensive plant behavior or even act as a sort of "vaccine" for local plants. Plants can choose which bacteria they want more of by secreting specific foods for that organism. There is even evidence that the effects of beneficial bacteria can endure across plant generations. Does any of this sound familiar? Maybe like a human digestive system, or the immune system? When we use pesticides or herbicides, we create an imbalance. Nature does not tolerate a void. Something will always fill it. The few pathogens that survive face little competition. They proliferate, giving rise to pathogenic communities that are resistant to future chemical applications. Sound familiar? Think antibiotic-resistant bacteria.

Fungi:

The mycorrhizae (the mycelium, or vegetative part of a fungus) increase the nutrient absorption of a plant an amazing 100 to 1,000 times. Mycorrhizae release powerful enzymes that help dissolve tightly bound soil nutrients including organic nitrogen, phosphorus, and iron. They also help their host plants access more water. In return, the plants give the fungi carbohydrates, vitamins, and enzymes. It is hard to imagine, but true, in one thimbleful of healthy soil, you can find several MILES of fungal filaments. Mycorrhizae also help plants communicate. Think of them as telephone wires transmitting information, quickly, from one plant to another. To communicate, they secrete soluble chemicals that warn neighbors of herbivore attacks, alert each other to threatening pathogens, communicate about impending droughts, and even help plants recognize kin. One study in 2009 documented a fungal network that wove its way through an entire forest, with each tree connected to dozens of others over distances of almost 70 feet. Mycorrhizae can benefit trees, vegetables, herbs, and even grasses (think your lawn). One exception of a plant family that doesn't use mycorrhizae is the mustard family (broccoli, cauliflower, Brussels sprouts, cauliflower, mustard, rapeseed).

How can I create my own healthy soil ecosystem, you might ask? Excellent! Because I have some tips for you.

Go organic. These microorganisms will not thrive if you use pesticides or herbicides.
The soil must be undisturbed. This means no-tilling, plowing, etc.
You can purchase both beneficial bacteria and mycorrhizae powder to apply to your plant roots. Find them at specialty gardening stores.
The powders must be applied to the roots of your plants within 48 hours of activation (the addition of water) or they will die.
The best time to apply this mixture is when you have access to the roots, ie: when you plant.
To apply the microorganisms, you can rub a small amount of the powder directly on the roots.
You can also rub a small amount on seeds before planting. It is helpful to soak the seeds first in kelp or comfrey tea.
What about the plants that are already in the ground, you might ask? Not to worry! You can also add the powder to water, making a liquid to spray on your garden or lawn.
To avoid disturbing the soil in the future, you can top-dress your garden by sprinkling a blend of good compost and topsoil over your garden each year. Just shovel the new amendments over the top of the soil in the spring and leave the soil alone.

I’ve heard the saying that what successful gardeners really grow is healthy soil. I hope these tips help you to improve your soil and your garden.