MYTH BUSTERS

MYTH BUSTERS SERIES

IN THIS SERIES the Thompson Shuswap Master Gardeners will break down commonly held gardening myths and uncover the truth behind them.

These posts will debunk prolific gardening myths and will include alternative environmentally responsible gardening methods based on research by Dr. Linda Chalker-Scott, Robert Pavlis, and various University Extensions.

Posters of these commonly held gardening myths are included as .pdf documents at the bottom of this page.

MYTHS:

• Banana peels make great fertilizer
• The best way to plant trees and shrubs is to add soil amendments to newly-dug hole
• Drought-tolerant plants don't need to be watered
• Epsom salt is one of the most perfect nutrients for gardens and plants
• Adding aspirin to Christmas tree water makes the tree last longer
• A bleach solution is the best choice for disinfecting pruning tools
• Add sand to clay soil to improve its texture
• Bone meal is an indispensable soil amendment every gardener should have on hand
• Mist houseplants daily during the winter months
• Coarse material placed at bottom of container creates better drainage for gardens and plants
• Dish soap is a safe, natural pesticide
• You shouldn't disturb the rootball when transplanting trees and shrubs
• Newly planted trees should be staked firmly and securely
• Ponderosa pine needles significantly lower soil pH (increase soil acidity)
• Fresh wood chips used as a mulch leach nitrogen from the soil
• Eggshells and antacid prevent blossom end rot
• All cactus, including holiday cactus, thrive in hot temperatures
• Fact vs Fiction

 

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MYTH:  Banana peels make great plant fertilizer

THE FACTS

Buried Banana Peels or Banana Peel Tea

Banana peels are essentially just another form of plant-based organic matter – there’s nothing unique about them

• Banana peels need nitrogen to break down, which means they actually remove nitrogen that plants need for greening.
   
• Banana peels do contain minerals, especially potassium and magnesium, but potassium and calcium aren’t seriously lacking in garden soils.

The best thing to do with banana peels is add them to regular compost!

Source:   
ROBERT PAVLIS
https://www.gardenmyths.com/banana-peels-garden/

 

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MYTH: The best way to plant trees and shrubs is to add soil amendments to newly-dug hole

THE FACTS

Adding organic matter, fertilizer or other substances to the planting hole of a LARGE TREE or PERENNIAL SHRUB can REDUCE plant growth

Adding amendments to backfill promotes root growth, but

- Roots and water DO NOT move well across the interface between amended soil and native soil 

• when roots hit the edge of the hole and encounter natural soil, they can circle back into the amended soil and create a ROOT-BOUND plant

- If organic amendment is not completely decomposed it may cause large trees and shrubs to settle

• The root collar may sink below the soil and predispose the plant to a host of health problems.

USE ORGANIC AMENDMENTS AS A TOP DRESS AROUND TREES AND SHRUBS

Sources:
Oregon State University Extension
https://www.oregonlive.com/hg/2017/02/gardening_myths_debunked_by_or.html

Washington State University Extension
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/soil-amendments.pdf

https://s3.wp.wsu.edu/uploads/sites/2076/2015/05/C100-Planting-Trees-Shrubs-15.pdf

Root Washing
https://www.finegardening.com/article/root-washing-why-and-how-to-wash-roots

 

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MYTH:  Drought-tolerant plants don't need to be watered

THE FACTS

ALL plants NEED WATER.

Drought-tolerant plants are those that, once established, will survive receiving low levels of rainfall or watering.

Plants considered drought-tolerant typically have EXTENSIVE root systems.

Newly-installed trees or shrubs, drought-tolerant or not, LACK the root system needed to draw in sufficient moisture, thus require adequate irrigation to establish sufficient root systems.

• All plants need weekly watering during the first year, to establish roots.

A drought-tolerant, water-conserving landscape is not going to grow as quickly or vigorously as the same landscape under increased irrigation.

• No plant will grow vigorously without adequate moisture, but drought-tolerant species will survive prolonged droughts.

If water is available, many drought-tolerant plant species will actually use more water than typical landscape plants!

Sources:
WASHINGTON STATE UNIVERSITY EXTENSION
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/xeriscaping.pdf

OKANAGAN WATERWISE
https://www.makewaterwork.ca/plants/

 

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MYTH: Epsom salt is one of the most perfect nutrients for gardens and plants

THE FACTS

Epsom salt, also known as magnesium sulfate, is a naturally occurring compound that contains magnesium, sulfur and oxygen

There are MANY online recipes for using Epsom salt:

• as a FERTILIZER
• to treat PHYSIOLOGICAL PROBLEMS, such as blossom end rot
• to PREVENT TRANSPLANT SHOCK
• to DETER PESTS

NONE OF THESE RECIPES ARE BASED ON SCIENCE.
There are no scientific articles relevant to Epsom salt use in home gardens and landscapes and its use could create soil nutrient imbalances and cause injury to plants.

A SOIL TEST IS ABSOLUTELY REQUIRED BEFORE USING THIS CHEMICAL.

Source: 
WASHINGTON STATE UNIVERSITY EXT.
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/epsom-salts.pdf

https://research.wsulibs.wsu.edu/xmlui/handle/2376/13108

 

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MYTH: Adding aspirin to Christmas tree water makes the tree last longer

Add an aspirin (or chlorine bleach, borax, vinegar) to prevent bacteria from building up in the tree stand’s water reservoir. Or add corn syrup (or sugar, molasses, honey, soda) to nourish the tree. These are just a few of the additives promoted to make your Christmas tree last longer.

THE FACTS

Not one of the above-mentioned ingredients has been shown to do any significant good. Contrary, some ingredients may adversely affect the tree.

The best thing to fill a Christmas tree stand’s reservoir with is plain old tap water!

But the most important factor in keeping a tree adequately hydrated is the freshness of the tree trunk itself.

A fresh cut reopens pores that absorb water.

• It’s recommended you cut one-half to one inch off the tree trunk right before immersing it in the tree stand water.

Monitor tree stand water levels regularly – a tree can drink up to ONE LITRE OF WATER PER DAY, PER INCH of trunk diameter.

Lower the temperature in the room where the tree is situated. And locate tree away from fireplace and heating duct.

Source:
NATIONAL CHRISTMAS TREE ASSOCIATION
https://realchristmastrees.org/

 

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MYTH:  A bleach solution is the best choice for disinfecting pruning tools

THE FACTS

A bleach solution is NOT the best method for disinfecting pruning tools

Chlorine bleach is an oxidizing agent – it is CORROSIVE

• Bleach is POISONOUS TO PLANTS, more so than any of the other commonly used disinfectants
• Any bleach left on pruning tools will DAMAGE the tissues of the next cut.
• Prolonged contact between bleach and metal may cause pruning equipment to pit or discolour.
• Pits (small holes) caused by the corrosion can harbour microbes that may FURTHER damage plants.

Better Practice
Clean pruning tools with household cleaners such as Lysol.

Sources:
Dr. Linda Chalker-Scott
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Pruning.pdf https://s3.wp.wsu.edu/uploads/sites/403/2015/03/cloroxed-clippers.pdf

 

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MYTH: Add sand to clay soil to improve its texture

THE FACTS

This myth may stem from the fact that if clay is the smallest soil particle (leading to poor drainage) and sand is the largest soil particle (leading to fast drainage), mixing the two will create a well-drained soil.

BUT

• When sand and a clay soil are mixed together, the large pore spaces of the sandy soil are filled with the smaller clay particles, creating a HEAVIER, DENSER soil
   
• To significantly change (not improve) the texture of clay soils, half the existing clay soil would need to be REMOVED and REPLACED with an equal volume of sand – an expensive, intrusive, and labour-intensive undertaking!

ORGANIC MULCH TO THE RESCUE!

One of the least invasive and most cost-effective ways to improve soil structure in clay is by the use of organic mulches.

• MULCH clay soil with COMPOST and/or a deep layer of WOODCHIPS  

Not sure of the TEXTURE of your own garden soil? See References for a link to an easy, do-it-yourself jar test.

Sources:
UNIVERSITY OF SASKATCHEWAN
https://gardening.usask.ca/articles-and-lists/articles-healthysoils/no-adding-sand-to-clay-soils.php

WASHINGTON STATE UNIVERSITY
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/soil-amendments-2.pdf

SOIL TEXTURE ANALYSIS (Jar Test)
https://hgic.clemson.edu/factsheet/soil-texture-analysis-the-jar-test/

 

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MYTH: Bone meal is an indispensable soil amendment every gardener should have on hand

THE FACTS

Bone meal supplies high levels of phosphorus and calcium.

Phosphorus and calcium are required for plant growth, but both (especially phosphorus) can cause problems if they occur in high concentrations. 

• Phosphorus and calcium are RARELY LIMITING in non-agricultural soils.
• High levels of phosphorus INHIBITS GROWTH of mycorrhizal fungi, causing the plant to put additional resources into root growth AT THE EXPENSE of other tissues and functions.
   

AND … its odor attracts dogs and other animals

Source:
Dr. Linda Chalker-Scott
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/bonemeal.pdf

 

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MYTH:  Mist houseplants daily during the winter months

THE FACTS

Most houseplants like a more humid environment than you do, and it can be a real struggle providing our plants with the levels of humidity they require during the dry winter months.

There are several scientifically proven ways to keep your plants healthy and happy during the winter months. But, contrary to popular belief, MISTING is NOT one of them:

Indoor temperatures evaporate moisture QUICKLY!

• Misting provides only temporary (five minutes) atmospheric moisture around your plants
• To really give your plants a more humid growing environment you’d need to mist them EVERY 10 MINUTES!

Better practice

• Cluster plants in groups to collectively raise the humidity in their area
• Plants naturally release water through their leaves (transpiration).
• Consider using an automatic HUMIDIFIER in the room or congregate your plants near BATHROOMS and KITCHENS, where they can absorb moisture from showers and cooking activities.
• Keep humidity-loving plants away from cold drafts and sources of heat such as fireplaces, ovens, and electric heaters.

Source:
UNIVERSITY OF GEORGIA EXTENSION
https://extension.uga.edu/publications/detail.html?number=B1318&title=Growing%20Ind oor%20Plants%20with%20Success

 

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MYTH: Coarse material placed at bottom of container creates better drainage for gardens and plants

THE FACTS

Placing sand, gravel, pebbles or pot chards in the bottom of a container before potting houseplants or outdoor plants OBSTRUCTS water movement.

Water doesn’t travel easily from layers of finely textured material to layers of more coarsely textured material

• ​​Water stops when it reaches the coarse material which can cause roots to sit in SOGGY SOIL.
• The coarser the underlying material, the more difficult it is for water to move across the interface.

ENSURE CONTAINERS HAVE DRAINAGE HOLE(S) AND USE THE SAME PLANTING MATERIAL THROUGHOUT THE ENTIRE CONTAINER TO ENSURE AIR AND WATER MOVEMENT.

Source:
Dr. Linda Chalker-Scott
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/container-drainage.pdfs

 

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MYTH:   Dish soap is a safe, natural pesticide

THE FACTS

Most dish soap products are not true soaps, but powerful surfactants called detergents. They can contain phosphate, bleach, enzymes, dyes, fragrances and rinsing aids

• TRU SOAPS are made from natural oils and fats.
   

Spraying a plant with diluted dish soap removes the plant’s natural defences against pests and diseases.

Dish soap alters everything it comes into contact with, including BENEFICIAL insects.

DISH SOAPS (DETERGENTS) ARE NOT AN ORGANIC ALTERNATIVE TO PESTICIDES AND ARE NOT APPROPRIATE FOR PEST CONTROL IN GARDENING.

Source:
GARDEN MYTHS by Robert Pavlis  

 

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MYTH:  You shouldn't disturb the rootball when transplanting trees and shrubs

THE FACTS

Plants with woody roots often need corrective root pruning before transplanting.

• Containerized plants are notorious for concealing fatal root flaws  (i.e. girdling roots).
• Bare rooting container plants is a more successful transplanting technique – root flaws can be corrected, and container media removed.

In a healthy, well-watered plant, root pruning at transplant time will induce vigorous new root growth and assist in establishment.

Reference:
DR. LINDA CHALKER SCOTT
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/fragile-roots.pdf

ROOT WASHING
https://www.finegardening.com/article/root-washing-why-and-how-to-wash-roots
 

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MYTH: Newly planted trees should be staked firmly and securely

THE FACTS

Tree staking is seldom necessary, but when trees are staked, they are typically staked TOO HIGH, TOO TIGHTLY, and for TOO LONG.

• Improperly staked trees grow taller than wider.
• When a tree stake is removed, a lack of trunk and root development makes the tree vulnerable to breakage or blow-down.

Newly planted trees CAN require staking if:

• They are bare root;
• The stem bends excessively when not supported;
• The planting site is very windy.

PROPER STAKING TECHNIQUE, IF REQUIRED

• Place stakes as low as possible – no higher than 2/3 the height of the tree;
• Affix tree to stake with a flexible material that allows movement all the way down the ground;
• Remove all staking material after roots are established (as early as a few months).

Source:
WASHINGTON STATE UNIVERSITY EXTENSION
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/staking.pdf

 

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MYTH:  Ponderosa pine needles significantly lower soil pH (increase soil acidity)

THE FACTS

Pine needles themselves are acidic but they do not have the capacity to appreciably change the soil pH (make it more acidic).

• Pine needles break down naturally and the microbes (decomposers) in the soil neutralize them.

Pine needles can be used to mulch shrub borders, flower beds and vegetable gardens

• Not just acid-loving plants like Azaleas, Rhododendrons, and blueberries.

Sources:
OREGON STATE UNIVERSITY EXTENSION
https://extension.oregonstate.edu/news/myth-vs-reality-whats-truth-behind-some-common-gardening-practices

UNIVERSITY OF NEW HAMPSHIRE EXTENSION
https://extension.unh.edu/blog/2019/10/do-pine-trees-pine-needles-make-soil-more-acidic

 

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MYTH:  FRESH WOOD CHIPS USED AS A MULCH LEACH NITROGEN FROM THE SOIL    

THE FACTS

SAY YES TO THE CHIPS!

FRESH wood chips, when used as a MULCH, do NOT leach nitrogen from the soil.

In areas where TREES and SHRUBS are a dominant feature of the landscape, arborist wood chips have been cited as superior mulches for enhanced plant productivity and represent one of the BEST MULCH CHOICES.

So go ahead and say YES to the local arborist looking to unload wood chips for FREE!

• Wood chips are composed of bark, wood, and leaves chipped into different sizes. This diverse mixture provides a hearty supply of nutrients.
• Wood chips provide incredible WEED CONTROL in ornamental landscapes.
• Woody mulches do NOT acidify soils and are the LEAST flammable of the organic mulches.

*Wood chips should be placed only on the SOIL SURFACE of trees and shrubs (not tender annuals or vegetables). If fresh wood chips are tilled into the soil, nitrogen could become tied up during the decomposition process, making the nitrogen inaccessible to plants. 

Source:
Dr. Linda Chalker-Scott
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wood-chips.pdf

 

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MYTH:  EGGSHELLS AND ANTACID PREVENT BLOSSOM END ROT

THE FACTS

Blossom end rot appears as a sunken, leathery, brown to black spot on the blossom side of a fruit in tomatoes, peppers, eggplants and some cucurbits.

BER is associated with a lack of sufficient calcium in developing fruit and conventional wisdom holds that calcium-rich amendments like EGGSHELLS and ANTACIDS (i.e. TUMS) can help prevent BER.

• Eggshells and antacid may help with BER if soil is lacking calcium, but most soils are not lacking calcium.
• A soil test is recommended to determine whether soil has a calcium deficiency.
• BER typically affects the earliest maturing fruit of the season and may be traced to EXCESSIVE SOIL MOISTURE or DROUGHT STRESS (especially fluctuations between too wet and too dry) or EXCESS FERTILIZATION, all which hinder the uptake of the calcium required for a plant’s health.

PREVENTIVE MEASURES

• Plant fruits in well-drained soil
• Maintain consistent levels of soil moisture (water deep)
• Mulch plants well
• Fertilize less

Source:
WASHINGTON STATE UNIVERSITY EXTENSION
http://gardening.wsu.edu/blossom-end-rot-of-tomato-and-pepper/

 

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MYTH:  ALL CACTUS, INCLUDING HOLIDAY CACTUS, THRIVE IN HOT TEMPERATURES

THE FACTS

Many of the plants labelled as CHRISTMAS cactus are THANKSGIVING cactus, or of blended ancestry.

Christmas cactus and Thanksgiving cactus are closely related, so it’s easy to mistake them for the same plant. Both plants are in the genus Schlumbergera:

• Thanksgiving Cactus (Schlumbergera truncata)
• Christmas Cactus (Schlumbergera bridgessii)
  - Not often grown commercially

Thanksgiving and Christmas cacti grow in the mountains of southeastern Brazil, so prefer things on the cool and shady side, unlike cacti found in desert habitats.

• Optimal temperature for Holiday cacti is 20 degrees Celsius (68 degrees Fahrenheit)        
• Large fluctuations in temperature can cause the cactus blooms to drop before they open
  - Place in a cool place – away from heaters and fireplaces – without drafts.

Holiday cacti are short day plants so to induce the plants into bloom they must have 12-24 hours of darkness and cool temperatures.

• The natural light cycles we get in winter will suffice.
• The plants enjoy bright light but not direct sunlight.

The plant’s soil should be dry to ONE INCH below the surface before watering and NOT fertilized or repotted while BLOOMING.

Source:
IOWA STATE UNIVERSITY EXTENSION
https://www.extension.iastate.edu/linn/news/it-thanksgiving-christmas-or-easter-cactus

 

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FACT vs FICTION

IT’S LIKE MAGIC – just type a gardening question into the Google search bar and voila – thousands of results pop up right before your eyes!

Whether a new or experienced gardener we’ve all done it – followed well-intentioned advice trusting that the advice was reliable, relevant and unbiased, when it wasn’t.

There’s lots of good gardening advice that’s been passed down through the generations, but some incorrect recommendations have trickled down as well. Which makes it that much more important to understand the WHY behind the advice we follow.

Yes, we should be open to the gardening wisdom of the past, but not at the expense of critical thinking. As stewards of our environment, we need to continually evaluate the effectiveness of horticultural practices, old and new.

TIPS FOR NAVIGATING THE DIGITAL SEA OF INFORMATION

• Gardeners with personal blogs may make claims based only on their own experiences. If you can’t find any sources cited for the information, consider that a RED FLAG!
• When you perform a standard Google search include the word

extension or suffixes such as edu, gov or org in the domain name.

University Extensions have already performed much of the research for you and present it in an easy-to-understand language.

• When you arrive at a website, look at how it’s organized. Does it end in .com? If it’s a business, there may be a bias in favour of advertisers and their products.
• For videos, start with extension YouTube channels (see two extensions in References) or visit Good Gardening Videos – 1,000 gardening videos curated for accuracy and quality.

Sources:
Oregon State University Extension – https://extension.oregonstate.edu/gardening

Dr. Linda Chalker-Scott – Washington State University –https://puyallup.wsu.edu/lcs/

Garden Professors – https://gardenprofessors.com/

University of British Columbia Botanical Garden – Hortline Advice

https://botanicalgarden.ubc.ca/advice/hortline-garden-advice/