Understanding mycorrhizae

For most of us, it is frankly difficult to have fond feelings toward fungi.We fixate on its texture - sticky or slimy, or its appearance -remember 'dog vomit fungus'?

But fungus in the soil is a vital decomposer of organic material and fungus that colonizes the roots of some plants contributes mightily to their health and vigor. In fact, the (symbiotic) friendly fungus mycorrhizae (pronounced my-core-rise-a) seems to create a partnership with the plant root, saying in essence, "Give me a share of the sugars for food and I will extend your root system so we both may eat better."

Here is how the fungus functions:
   1. Mycorrhizae are found in some amount in almost all soils that have some degree of organic material in them. A soil that is sterile by design (sterile potting mix) or by chance (highly sandy soils) will have a very small amount (or no) mycorrhizal activity.
   2. There must be organic material in the soil for the mycorrhizae to feed on.
   3. There are two main types of mycorrhizae
. One, the ectomycorrhizae,is most often found around the roots of trees where the fungal mycelium (vegetative portion of the fungus) forms an extensive nutrient-gathering network within the soil and leaf litter (see photo above). Ectomycorrhizae (those that live outside the root's cell walls) are generally found in about 10% of plant families, primarily trees (but for us, it is important to know that this fungal relationship is also favored by pines and roses).

The second primary type of mycorrhizae is the endomycorrhizae (or that which will penetrate into the roots and cell membranes) which tend to produce what appear as lumpy nodes on plant roots. This kind of mycorrhizae is found in approximately 85% of the plant families.

Fossil evidence suggests that the plant/mycorrhizae food-sharing behavior (mutualism) appeared 400-460 million years ago.

Equally interesting is the fact that the lumpy structures (arbuscules) produce a glycoprotein, glomalin, whose function is to store carbon in the soil.

   How can this help us garden?

Research seems to indicate that the use of mycorrhizae helps reduce transplant shock, promotes and supports vigorous root growth and, some suggest, increases disease resistance.

Mycorrhizae is emphatically not a fertilizer or soil ammendment. It works most effectively when used correctly with the plants it is associated with and in soil that has 2-4% humus and is mulched.

Mycorrhizae is widely available in powdered form ready to be mixed, following directions, into garden soils. Check with Warne Chemical in Rapid City for both the dry mycorrhizal formulations for adding to the soil prior to planting and the powder that is to be added to water to make a dip to be used pre-planting for bare root plants. Inquire also at the locally owned nurseries and greenhouses for mycorrhizae in smaller packets.


Miss Gardening? Grow Green Beans Indoors This Winter


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For gardeners who just can’t stand to keep their hands out of the soil for any length of time, growing food indoors in containers can be a great pastime during the winter months.


Green beans are a relatively quick-growing vegetable that can be grown inside your home and also look quite beautiful, as well.


Plants that you are growing indoors can be started any time of the year, but you still need to remember that they have certain environmental requirements. Green beans need plenty of light, so you will need to place them in a part of your home where they can get a minimum of six hours of sunlight each day. Alternatively, grow lights can work if you do not have a window that gets enough sun.