Mycorrhizae Are The “Engine That Could” For Superior Plant Growth
Mycorrhizae are a group of soil fungi that are some of the most important micro organisms you need to add to your garden. Mycorrhizae are plural and mycorrhiza is singular. Typically one uses the plural form because most blends sold to consumers contain multiple species of this type of fungus from a few different genera. And, it is hard to find just one type of these in a teaspoon of good garden soil. There are probably scores and scores of species in this small amount of soil.
These are the first of the micro soil organisms I plan to expose you to understanding a bit better. You may have to check back periodically until I have had a chance to show you the difference of growth rates for both the plant and the especially the roots of plants that have been inoculated. I have these great ideas for new blogs but am not usually prepared to share pictures of what I am trying to impress upon you. Yet, this is so important to all gardeners whether traditional soil or hydroponic that one should be prepared to rejuvenate your plants without delay. I will begin with the posting of the stage where these lettuce seedlings are both the same age, growing in similar size containers, watered the same day, growing side by side so that they receive the same amount of sun. Keep an eye on the container on your right. This is the one I treated with my favorite mycorrhizae blend after I took the image.
Mycorrhizae are thought to have evolved in conjunction with plants. Fossil records suggesting an inter-relationship has existed for hundreds of millions of years. Many believe it was because of them that plants were able to leave a total water environment and venture onto land where together they quickly transformed the world into an Eden. The mycelium or vegetative body parts of the fungus are extremely fine. The fine threads are quite a bit smaller than any root you may see on a plant. The mycelium, the thread like part of the fungus, is so fine they are able to capture moisture and nutrients far more efficiently than even the smallest plant root. There are so many of these fibers per cubic centimeter that the total volume greatly overshadows that of a plant root. It is just this special feature that plants have come to rely upon mycorrhizae.
Mycorrhizae form a symbiotic relationship with plants. They provide water and raw nutrients to the plant and the plant supplies needed glucose for the fungi to live. Fungi are unable to produce their own food. There are some instances where it is believed that the mycorrhizae may have a parasitic relationship with plants. This is a bit complex to evaluate properly. Because there are a huge variety of mycorrhizae and each has a different specialty function understanding the complex relationship will be a part of the emerging biological studies for quite a number of years to come. Broadly speaking there are two forms of interaction mycorrhizae can take with a plant root. Even this generalization is quickly being challenged as more is understood about these important fungi. Endomycorrhizae are those species that penetrate the root cells. They form sort of balloon shaped areas inside of the cytoplasm of the root cell to better facilitate the transfer of nutrients back and forth between each other. Ectomycorrhizae for the most part do not penetrate the root cell itself. These tend to closely surround the cell and transfers occur because of the close spacing between the root and the fungi. Some ectomycorrhizae will penetrate a root cell though as a general rule do not. I have seen that a third type may be considered. This one is being thought of as a maintenance type of mycorrhizae. It is being proposed that these compact fungi with mycelium that do not travel far from the body may interact with the plant by controlling naturally made pollutions or even providing nutrients from dead organic material not yet decayed.
Much understanding about the thousands of types of these fungi is a fast emerging field of plant biology. It is not terribly important to understand the different types or how they function in relation to a plant. What is far more interesting is that these tiny fungi are able to transport water and nutrients with an efficiency that is truly amazing. It has been shown that some types of mycorrhizae are able to transport phosphorous to a root in a higher Ph soils. It has been shown that some mycorrhizae are able to control the amount of nitrogen a root will be allowed to absorb during times when nitrogen is in low concentrations. It has been shown that mycorrhizae are able to control and funnel water to roots when the scarcity of water is low. There are some that primarily seek and funnel specific micro nutrients like zinc and control its flow to a plant in a manner that benefits both plant and fungus. It is suggested that soil fungi help protect plants from disease and other pathogens more efficiently. They do this sometimes by battling the pathogen themselves and of course through their ability to transport nutrients create a happy healthy plant which is better able to defend itself from trouble.
It is important for the home gardener to remember that these fungi are quite delicate. They are easily destroyed when soil is disturbed. Many urban areas are distinctly low in them due to construction which sterilized large areas with the movement of soil to build houses and other buildings. For hydroponic growers this is even more important since a sterile media is usually used for growing plants. Without the addition of mycorrhizae even these plants that are bathed in a blend of nutrients just waiting to be taken up by the plant are greatly reduced.
I read somewhere that it was the forest hardwood “farmers” who introduced inoculating new plantings with mycorrhizae that we owe our thanks for promoting this technique. These fungi have been known since the early half of the 19th century. They could be seen under a common microscope. They were first studied officially by Franciszek Kamienski from 1879-1882. They were first called mycorrhiza by Albert Bernhard Frank in 1885. Yet, to me, it was the hydroponic folk who brought this out into the light. In fact, I feel it is the hydroponic garden specialists that seem to be examining the complex inter-relationship between the diverse micro organisms of fungi and bacteria we owe a great deal of thanks.
History aside, mycorrhizae are the first of these micro organisms you really need to begin using in your garden. I do this at the time I plant a new plant or even when I divide and replant. Remember these are delicate to the point that dividing a plant will have killed most of them off. I have a preferred blend I like to use that I have provided a link to after this paragraph. This particular blend contains another soil fungus I like that acts as a security patrol controlling other fungus pathogens. This genus is call Tricoderma. The hydroponic people do not like to use Tricoderma in their blends. They generally use sterilized media to give plant roots a place to call home. They feel the Tricoderma is not only unnecessary but may in fact harm the good endo and ecto mycorrhizae for their own survival. This would mean a reduction of the remaining few mycorrhizae to help the plant roots absorb the dissolved nutrients. I like to make sure Tricoderma is part of the blend because of its ability to ensure the health by feeding on naturally occurring fungus pathogens.
One last bit of advice is that even if you move towards a low soil disturbance gardening philosophy, like I have, you should still occasionally provide mycorrhizae to established plants. Everything is food to something else in nature. Mycorrhizae are themselves prey to other micro organisms. Also, Tricoderma have been shown to not travel far from a food source. Once they have consumed their prey they literally starve to death. They become extinct in that location until re-inoculated. My favorite method of treating established gardens is to add some inoculate to my compost tea I use to give special treats to my plants. One can also add a good mycorrhizae blend to your dry fertilizer and spread it that way. I saw one large brand lawn fertilizer now advertising the addition of mycorrhizae to their formula. Many of the large soil producers like Pro Mix and Fox Farm Ocean Forest and all the others have inoculated their soil blends so you don’t have to do this separately. This is nice but I still add some concentrate even to these blends. One doesn’t really know how old the blend is. Sometimes a blend is rather “wet” and I fear that this moisture may have encouraged the fungi spores to begin growing and looking for a plant to interact with. Not finding any and already actively growing is bad for a fungus without a food source. I have a 2 acre garden area I maintain and rarely go through more than a pound container a year. This roughly $20 investment is a small drop when one considers that less fertilizer is necessary with these little “engines that could” and do.