Are you connected to Earth’s Natural Internet?
By Bob Dailey
There is a fungus which grows in the soil on and around plant roots that is absolutely essential for plant health. In fact, this fungus is so important that some plant species cannot exist without it. Named mycorrhiza, which literally means “root fungus,” this organism creates a symbiotic relationship with plants. The amazing properties of this root fungus has prompted scientists to call it “Earth’s natural internet.”
If one digs into leaf mold, or into really good soil, tiny white filaments resembling spider webs can be seen spreading through the soil or leaves. This is mycorrhiza. Though deceptively small, a teaspoon of good soil can have eight or nine feet of the tiny strings.
Mycorrhizal fungi create a symbiotic relationship with plant roots, taking in minerals from the soil and delivering it to the plant, in exchange for sugars produced by the plant. Plant biologists have estimated that 95 percent of the plants investigated are either partially or completely dependent on these fungi- a testament to their importance. Orchids, for instance, are so dependent on mycorrhiza that even their seeds cannot germinate without it.
Once attached to plant roots, this fungus sends out tiny threads which extend out much further than the roots can extend. Though they look like plant roots, these white filaments are what absorb nutrients. Since they have a great deal more range than the plant roots themselves and have significantly more surface area, they are able to find and take in significantly more water and nutrients than the plant roots can. Scientists have also discovered that mycorrhiza can store up nitrogen when it is plentiful, and then release it to the plant when there is a lack of nitrogen in the soil. These fungi can also store water, which it releases to the plant in times of drought.
Plants that are not aided by these fungi may not be able to take up important nutrients such as phosphate or iron – which can lead to iron chlorosis or other plant deficiencies. Mycorrhiza can also play a protective role for plants in soils with high heavy metal concentrations, such as acidic or contaminated soils. These fungi are also suited for colonization of barren soils.
Soil-borne diseases (such as take-all patch and brown patch) are also serious problems for plants. Unfortunately, many residents are quick to apply fungicides at first signs of take-all or brown patch. While these fungicides will kill the bad fungi, it will also kill the mycorrhiza. A better method may be to inoculate the lawn with organic material that has high concentrations of mycorrhiza.
Studies are showing that plants colonized by mycorrhizal fungi are much more resistant to these and other diseases. Scientists have also now determined that mycorrhizal fungi can also transport nutrients and water from plant to plant through extensive underground networks.
Operations like tilling can also kill mycorrhiza, although aeration prior to adding organic matter will do relatively little damage to it. For floral or vegetable gardeners, many experts are recommending “no-till” methods.
There is a saying that one cannot be a good gardener if she (or he) has not killed at least a thousand plants. That said, there must be a large number of great gardeners.
Gardening mistakes can be time consuming and ultimately costly. Correcting some of these mistakes may sound counterintuitive, but understanding and avoiding very common errors helps create healthier and more attractive lawns and gardens.
- Overwatering encourages shallow root systems, stresses plants, wastes water and increases their susceptible to disease and pests. Watering every day is one of the largest mistakes. Water deeply, but only once or twice a week. Most plants (including lawns) go dormant during the fall and winter, so they don’t need much or any water.
- Too much fertilizer can cause real problems in the landscape. Too much fertilizer may kill beneficial microbes in the soil, actually encourage disease and requires extra water. Especially dangerous are chemical fertilizers which contain lots of salt. Salt kills organisms, and good gardeners know that the micro- and macro-organisms in the soil are important to soil and plant health. Additionally, fertilizer runoff is one of the largest polluters of our streams, waterways and esturaries.
- Kill all those bugs. The goal is to get the unwanted pests under control and the good ones encouraged. Using chemical pesticides kills beneficial soil organisms and the insects that keep pests and diseases at bay. Even organic pesticides should be used sparingly. As with fertilizers, pesticides leach into our water systems.
- Misdiagnosing a problem. Know thine enemy. Search the internet for answers or use the local master gardener hotline (if there is one in your area) to identify the problem and possible solutions. Contact the local extension service. There are probably a number of master gardeners in your area who would be happy to help you as well. Two good books for plant and garden care are The Vegetable Book, a Texan’s Guide to Gardening, by Dr. Sam Cotner and Doug Welsh’s Texas Garden Almanac.
- Non-native or non-adapted plants. Azaleas – yes. Palms – no. There are several great sources for native plants and ones that are adapted to the Gulf Coast region. One source is Earthkind. This site, produced by Texas A&M, provides hundreds of plants that are adapted to the region. Simply choose your region or input your zip code and the website will lead you through the rest. Another valuable site is Lady Bird Johnson Wildflower Center’s Native Plant Database, which will guide you to lists, planting instructions and habits of hundreds of native species.
- Right plant but wrong place. Think and plan before planting. Plants that love the sun probably won’t do well in a shady area. Plants that like dry, well-drained soil won’t be happy in a bog garden.
- Not preparing soil before planting. Healthy soil = nutrients and beneficial microorganisms = healthy plants. Use good, organic compost. If you are buying from a local compost operation, ask for specifics on the compost. Compost is generally sold by the bag, or by cubic yard. If buying from a big box store, check the labels to see if it discloses anything about the compost. Find A Composter is a good place to start.
- No mulch. Mulch helps the soil retain moisture, keeps soil at a more constant temperature and discourages weeds. As it decomposes, mulch adds nutrients to the soil. A word of caution. Those pretty mulches which are orange or black are probably dyed. The dye is not something to worry about, because it is made from soy-based dyes,.But the source of the mulch is something to worry about, especially if it discloses that it is made from “recycled” wood (mostly from shredded shipping pallets). Many of these pallets contain wood that has been saturated with chromated copper aresenate (CCA), as a preservative. The CCA can leach into the ground. It can also be taken up by the plant into leaves and fruit. If you must use dyed mulch, do not use it on your vegetable garden.
- Planting or pruning at the wrong time. Plant and prune trees in the winter when they are dormant. Don’t resod in the winter.Plant spring blooming flowers in the fall. Plant fall blooming flowers in the spring.
- Short-term thinking. How big is that little sapling going to get in five or 10 years? How much space will the one-gallon esperanza need in a couple of seasons? Remember that those little plants being well irrigated by your sprinkler system now may have a lot of trouble watering everyting when the plants get big. Consider installing drip irrigation in your beds. Drip produces no wastage, gets water down into the root systems where it’s needed and reduces your water bill.
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