Are bees only attracted to the colour yellow? Is cinnamon useful as a fungicide? Will putting sugar in the planting hole before you put in a tomato transplant make the fruit sweeter? Should you put gravel in the bottom of a houseplant pot?
There is a lot of information about all types of gardening out there, some of it handed down for generations by gardeners. Alas, to muddy the water in the watering can, there is plenty of misinformation too. In this issue, we explore a few common gardening myths.
Beating a fruit tree?
One of my favourite gardening myths claims whacking an apple tree will force it to produce more fruit. There is much controversy about where this originated, but many seem to think it came from the late garden writer Jerry Baker, who wrote a few books filled with often-questionable folk remedies for the garden. The problem is, the vast majority of his remedies had no scientific proof and some, like making a pesticide from nicotine, were dangerous. There’s no research prove beating a tree will prompt it to bear more flowers and fruit. So, spare your tree and use your bat for softball.
Watering midday can scorch plants?
It often rains midday in Atlantic Canada, followed by welcome sunlight. Do you see any signs of scorching from raindrops? Researchers have studied this and water droplets are too small to magnify sunlight and burn foliage. What watering midday will do is waste water through evaporation, and also raise the risk of fungal diseases due by increasing humidity around plants. It’s best to water your garden and your containers during cooler times of the day, such as early morning, giving them time to dry and reduce the risk of mildew eruptions.
Coffee grounds deter snails?
As reputable gardening scientists will regularly insist, adding coffee grounds to your garden won’t keep the slugs and snails away, but it will help with soil fertility. The most efficient way to use the grounds is to is to add them to your compost pile to allow them to break down, and then top-dress with the compost later. The same goes for banana peels, eggshells, tea bags, vegetable peelings and other food waste. They all contain nutrients, but most need to break down to make those nutrients available. Simply add these items to a worm bin or a traditional compost heap or bin and add the finished compost to the soil.
Cinnamon as a fungicide?
Most of us gardeners are keen to avoid using manufactured synthetic pesticides to battle pests. There are dozens of remedies and tonics touted around the gardening world, and one that has some validity is cinnamon, which does have antimicrobial and antifungal properties. It is sometimes used to prevent damping off fungus in seedlings, but one drawback is that there are many different species of cinnamon, which may have different levels of efficacy. Research on cinnamon’s antifungal properties is done in controlled laboratory conditions, and our gardens don’t offer the same conditions. Still, it’s worth adding cinnamon to your potting soil when seeding transplants; but most important is to use clean pots and labels, ensure good air flow around the seedlings and not to overwater.
Leave those rocks alone
Some people swear by putting stones in the bottom of plant pots, especially for indoor plants, to help with drainage. Don’t bother. I remember one of my soil chemistry professors talking about this, but without causing our eyes to glaze over with his tedious and complex explanation, adding crockery or pebbles to a plant pot simply reduces the amount of soil and root space available for your green darlings. If you need to have a well-draining potting medium for plants that don’t like wet feet, make or purchase planting mixes high in materials like perlite, coarse sand, or bark.
Save your sugar for your coffee
The idea is to add sugar to the hole before you add your tomato transplant, to make your tomatoes sweeter. It doesn’t work. The tomato’s genetics determine its sweetness, acidity, size, yield, and disease resistance. If you want sweet tomatoes, get transplants or seeds that describe the cultivar’s taste and sweetness. Or maybe sprinkle sugar on your sliced tomato for your sandwich.
Yellow flowers are best for bees?
Bumblebees, honeybees, and other species of bees see the world differently than humans. Like us, they have three photoreceptors in each eye that helps determine colours, but they are able to also see ultraviolet. They don’t have a photoreceptor for seeing red, so they prefer flowers that are yellow, blue, violet, and purple, but not exclusively yellow. There is plenty of ongoing research on bees and their sight and colour preferences, and interestingly they will come to red bee balm despite not seeing the flower as red. The best thing to do for pollinators is to plant a variety of nectar- and pollen-rich perennials, annuals, shrubs and trees with flowers in various shades to give them plenty of food sources.
Dish soap to deter bad bugs?
This is an “it depends” situation. If you’re going with a homemade solution, bear in mind that most dishwashing liquids are made with detergents, which can include chemicals that harm plants. If you are going to go with a soapy solution, use one tablespoon of pure castile soap, mixed with a litre of water in a spray bottle. You can also buy insecticidal soaps that are approved for organic gardening and farm use, and target specific pests.
Two cases where insecticidal soaps don’t work are with the dreaded Japanese and scarlet lily beetles. Your best organic option there is to hand pick and dispose of them in the garbage, not the compost. Spraying them with soap just makes shiny beetles, as one sage gardener told me.
Learn more
Looking for some reputable sources for gardening information? Universities, especially those with an agricultural orientation, often have excellent gardening fact sheets. One trusted site is Garden Myths, by Canadian Robert Pavlis, a highly experienced and educated gardening myth buster. He has a YouTube channel and writes short books, often free to readers. Another superb resource is the Garden Professors group on Facebook. It has a search option for looking up information on the group, and is run, as the name suggests, by professors of horticulture and agriculture.