Mythbusters: Gardening Edition

For a long time, I have wanted to do a post about all the many myths that float around in the gardening world. Things are quiet here today, so now I get my chance!

As a kid growing up, it seemed like my Uncle V_____ and Aunt V_____ had a lot of crazy ideas about how plants could cross — like not planting different vine crops next to each other because the fruits that come off them will be all messed up.  Even though I had a grade school education of science and biology at the time, that just didn’t seem right. Later, I found out, it wasn’t correct.

So, the time is now. Let’s bust those myths!

Myth #1: Pinch the seed pod off if the onion goes to seed. (

Busted!: Years ago that was a common practice because older (heirloom) varieties were prone to bolting. In today’s world with newer hybrids, if you pinch the seed pod off immediately it will keep the center core of the onion from growing and the end result is a smaller onion that will not store well.

Myth #2: Knock the tops of onions over to make larger bulbs. (

White Onion
Busted!: (And busted big time!) Actually the opposite is true. If you knock the tops over prematurely, that will stop the bulbing process and thus will make the onion more likely to grow during storage because they did not get all of their growing done when they were planted.  Onions will fall over on their own when they are ready to be harvested.

Myth #3: To get sweeter tomatoes, add sugar to the planting hole. (

Busted!: Sorry grannies, this is not true. Tomato plants can’t absorb sugar in the soil because it is too complex of a molecule for their metabolic pathway. They produce the sugars they have in the fruit via photosynthesis. The sugar content of a variety is predetermined in the plant’s genetics.
Myth #4: Perennials won’t bloom the first year, especially bare-root. (

Half Busted!: With modern breeding and growing techniques, this is no longer true. Go ahead and plant bare root and potted perennials now and enjoy those blooms the first year, assuming you don’t plant them past the time they naturally would bloom. However, if you buy a potted perennial that requires over-wintering, then you will have to wait through the first winter to get the desired blooms. It’s best to inquire from the seller to find out what to expect that first season after planting.

Myth #5: Plant peas and potatoes on St. Patrick’s day. (

Half Busted!: This can’t possibly be true for all climate zones. It’s much better to refer to the updated USDA hardiness zone map and plant according the local last-frost dates as recommended by local gardening experts. We assume grandma never moved far from where she was born so she must have lived her entire life in the same hardiness zone!

Myth #6: Pinch off all blooms of annuals before planting. (,default,pg.html)

Busted!: In many cases pinching is no longer an absolute must because today’s commonly available bedding plants are bred to be more compact with continuous blooms. So, you don’t need the pinch to manage growth or promote another flush of blooms.

Myth #7: Planting tomatoes in a trench or up to the first true leaves promotes a sturdier plant. (

Half-Busted!: This one is still true for seed propagated heirlooms and hybrids. Planting deeply does help elongate the rooting area since any point on the stem that comes into contact with the soil will root. The exception is when planting grafted tomatoes because if  the scion takes root it will negate the benefits of the grafted rootstock so never plant a grafted tomato too deeply.

Myth #8: Drought-tolerant plants do not need to be watered. (

Busted!: It doesn’t matter if a plant is a barrel cactus or water-guzzling bamboo; it needs water to grow. This is particularly true in its first year, when consistent watering is crucial for a plant’s survival. Another good time to give it a soak, of course, is during a drought.

Myth #9: Just-pruned trees should be coated with a seal to keep fungus out. (

Busted!: At one time bandaging a pruning cut while gardening was common practice. The problem is that this prevents the cut from healing properly and forming a callus. The better option is to make a clean cut outside the branch collar (where the branch connects to the trunk) and allow it to heal naturally.

Myth #10: You must have both male and female trees in order for them to bear fruit.
Half Busted!: It’s true that some fruit trees require the male and female of the species to be planted in close proximity to one another in the garden to produce fruit. These trees are called dioecious (which means two houses). An example would be the ginkgo tree. However, there are self-pollinating trees that provide their own pollen and fertilize themselves, such as peach trees and certain types of apricot trees.
Myth #11: Wood chips from diseased trees can spread pathogens to plant roots.
Myth!: Wood chips are a popular mulch material, but some gardeners get nervous about where those chips came from. If the original tree had an infection, mightn’t the chips spread the disease? As a result, many people let wood chips compost for weeks before they use them, thinking it kills leftover pathogens. But there’s no pressing need to compost the mulch, since no research has found that pathogens can leap from uncomposted wood-chip mulch through a few inches of soil to the healthy roots below. Dirt contains beneficial fungal and bacterial species that will outcompete pathogens. Still, do keep uncomposted mulches as surface dressing only. Keep them away from tree trunks, too, since a trunk’s moisture can serve as an incubator for infectious pathogens.

Myth #12:The more you fertilize, the better a plant will grow.
This is a common mistake. Many gardeners assume that the more of a product they use, be it fertilizers or pesticides, the better it will work. Instead, gardeners should follow directions on the package, regardless of how eager they are to have a garden in full bloom or the best lawn in the neighborhood.

And, because all of the old wive’s tales are not myths…

Myth: Use tuna fish cans around transplant stems to thwart cut worm.

Not Busted!: Yes, Grandma was correct and frugal with this tip! When both ends of the can are removed and placed around the plant, it acts as a barrier to keep these natural soil surface crawlers from reaching the plant until the stem has thickened past the tender stage.

Myth: Add chalk or egg shells to the planting hole.

Not Busted!: Again, a good tip, as both of these items will help prevent blossom end rot in tomatoes since they provide calcium to the fruit (since egg shells take a while to decompose, crush or grind the shells to enable them to dissolve faster).

Myth: Putting egg shell flakes around the base of plants will prevent slug damage.

Not Busted!: Yes, Grandma was right, slugs do not like to crawl over the jagged surface of sharp eggshells so putting a barrier of crushed (not ground too finely) egg shells is a great deterrent.

Myth: Beer traps for slugs

Not Busted!: Yes, they really do work. And there is even research to show they prefer the light beers over the darker ales and lagers. But, if you get a rain or water the plants, you will need to refill the traps with fresh, undiluted beer as those little critters avoid the watered down stuff.


© Mertie Mae Botanics LLC and Horticulture Talk!, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.


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