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Writer's pictureJennifer McDonald

Ask a Master Gardener: Garden Myths: Fact vs Fallacy

By: Barbara Boone, Mobile County Master


Many pursuits have myths which are purported to be tried and true. Gardening is certainly no exception. Sometimes the mythical origin is unknown. Perhaps Uncle Zeb had a successful tomato harvest, attributing his bounty to one of the following “amendments” to his garden. He then passed along his success to neighbors, friends, social media, and it spread far and wide as truth. All this without a scientific trial including test subjects, standards, and controls to distinguish fact vs fallacy. In fact, Uncle Zeb is touting an unverified hypothesis. Let’s see if his additions agree with scientific fact, or if he just had blind good luck!


·         Coffee Grounds 

Coffee grounds get a lot of press for contributing nitrogen, phosphorous, potassium (N-P-K) and micronutrients such as calcium, zinc, iron, and magnesium to soil. However, these nutrients must be decomposed by soil microbes before they are available to plants. This takes time so plants will not have these nutrients available until much later. In addition, coffee grounds do not have the concentration of nutrients that will replace fertilizers needed to promote growth. The fact vs fallacy needle points to fallacy. Best case: add coffee grounds to a compost pile.

 

·         Eggshells

Other kitchen by-products, eggshells and eggshell water, have been touted as providers of calcium. The main component of eggshells is calcium carbonate which plants need for growing leaves and roots. Calcium deficient tomatoes also develop blossom end rot, a sign of inconsistent watering. The issue with eggshells providing calcium is that a huge amount of ground eggshell is needed to have a meaningful effect in the root system. The fact vs fallacy needle points to fallacy if only a few eggshells or boiled eggshell water is added to soil. Best case: add ground eggshells to a compost pile and water plants consistently.

 

·         TUMS

TUMS has calcium carbonate as its main active ingredient, along with magnesium and sodium. Gardeners using TUMS need to mix about 80 tablets in the soil per plant. This is not an efficient use of time or additives. The fact vs fallacy needle points to fallacy. Best case: save TUMS for heart burn and perform a soil test. Again, water consistently.

  

·         Epsom Salts

Another plant additive used in the home gardens to grow bigger and better fruit is Epsom salt. Epsom salt is magnesium sulfate (MgSO4), which does provide magnesium and sulfur, both important nutrients. However, magnesium should not be added unless a soil test indicates a deficiency because highly concentrated magnesium could negatively impact soil and plants. The fact vs fallacy needle is pointed in the middle. Best case: use this product to soak your aching feet while waiting for soil test results.

 

·         Banana Peels

Bananas are known to contain potassium, a major plant nutrient which boosts flower and fruit production. A DIY method of adding potassium is a tea made of banana peels steeped in water. Like eggshells, an entire plantation of banana peels would be needed to make such a tea because fresh bananas are 80% water; not a sufficient concentration to produce real results. Also, adequate time would be needed for potassium to leach into the tea. The fact vs fallacy needle points to fallacy. Best case: soil test and if needed, use a fertilizer adding enough K to N-P-K. In the meantime, a peanut butter and banana sandwich would be a better use of this fruit.

 

·         Hydrogen Peroxide

Hydrogen peroxide (H2O2) is mainly used as an over-the-counter disinfectant, typically in concentrations of 10% or less. Some gardeners claim that H2O2 can cure plant disease. The issue with H2O2 is that it works in conjunction with other compounds, so it does not have enough time to move through plant tissues to kill a bacterial or fungal pathogen. In fact, excessive use may kill off beneficial microbes. The fact vs fallacy needle broke on the fallacy side. Best case: use for personal wounds and not on your plant.


All the above are additives some gardeners have used in their own landscape. As indicated, each additive points to fallacy and it has not been scientifically proven otherwise. Uncle Zeb should reassess use of untested amendments in his garden. Maybe he should talk to his plants instead. After all, it is said that the best garden amendment is the gardener’s shadow. (Anonymous)



Good for your garden...or not so much?

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