Tidewater Gardening - July 2012

Gardening Myth Busters
K. Marc Teffeau

You have probably seen the program called Mythbusters on the Discovery Channel. Two guys and a supporting crew like to prove or disprove all kinds of supposed truths. They shoot things, blow things up and generally involve themselves in all sorts of constructive and destructive mayhem. Well, the gardening world also has its share of supposed correct gardening practice “myths.” Some are true and some are not. To my knowledge, the cast has not taken on these myths for proof or debunking.
Recently, Diane Blazek at the National Garden Bureau looked at some of these gardening tips that we assume to be true, as they were either passed down through the family from your grandmother or received from a neighbor or some other source.
I remember my grandmother on my father’s side always planted her vegetable garden by the signs of the moon. I, the scientific type, was always skeptical, but it was hard to argue with the success that she had each season. So, what are some of these common gardening tips that the NGB looked at?
How about putting sugar in the planting hole for sweeter tomatoes? Not! Busted! Now I don’t remember my grandmother doing this one. Tomato plants, or any plant species for that matter, can’t absorb sugar through their roots in the soil. Producing sugars is what photosynthesis in the leaves is all about. The sugar content of a variety is predetermined in the plant’s genetics and nutrition. I would imagine, however, that the ants in the garden would love for you to provide for their sweet tooth.
Did you know that one of the reasons your cantaloupes may not be as sweet as they should be is that the soil is deficient in magnesium and boron? These two elements are important in the sugar production process in the fruit. One suggestion is to apply a mixture of 3.5 tablespoons of Epsom salts plus 1.5 tablespoons of a 20% boron material (check the detergent section of the supermarket) per gallon of water to improve flavor. Apply this mixture when the vines begin to run and when the fruit is 1 to 2 inches in diameter.
How about adding chalk or egg shells to the planting hole? Not Busted! This is a good tip as both of these items will help prevent blossom end rot in tomatoes as they provide calcium to the fruit. Blossom end rot is the result of a calcium imbalance in the fruit. It usually hits the first fruit set and after that set comes off the plant balances itself out.
However – if your soil is deficient in calcium, you can use egg shells, but they take a while to decompose. Speed this process up by crushing or grinding the shells to enable them to dissolve faster. Better yet, get a soil test of your vegetable garden soil every year to make sure your soil pH is correct. Liming will provide the needed calcium and phosphorous that the plants will need.
When planting annuals in the landscape, the common practice has been to pinch off any blooms before transplanting. I have been guilty of making this recommendation for many years, but now I’m Busted! According to the NGB, 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 to pinch to manage growth or promote another flush of blooms.
The standard story with perennials is that they won’t bloom their first year, especially if you plant them bare-rooted. With the explosion of so many new varieties of perennials that has resulted from improved breeding programs and growing methods over the last 10 to 15 years, this is only half true. Go ahead and plant bare root and potted perennials now and enjoy those blossoms the first year, assuming you don’t plant them past the time they naturally would bloom.
Some herbaceous perennials, but not all, still require a vernalization period. This means the plant needs to over-winter for it to flower the next growing season. In this case you will have to wait through the first winter to get the desired blooms. Do a little homework ahead of time about the perennial you want to purchase, check with the garden center where you will purchase it or the garden catalog description if you are going to buy it by mail order.
The orange day lily, Hemerocallis fulva, is very common in our area. Naturalized from the gardens of the early settlers, these lilies are a common sight as they grow wild along roadsides, ditch banks, power lines and railroad beds. In fact, another common name for this plant is the railroad lily.
The flowers are large (about 3½ inches across) and showy and last for only one day. Because there is a succession of blooms, the flowering period for this lily lasts about one month, starting in late May and ending some time in early July. Its abundant spread causes some people to think that it is invasive. Day lily flowers (Hemerocallis) actually aren’t in the lily (Liliaceae) plant family, though the blossoms do resemble them.
We have day lilies around our house and the other day my wife picked a bunch for a display on the kitchen table. Over breakfast she asked me why some flowers close at night, like these lilies and morning glories.
Many flowers have petals that are open during the day, but close up at night. These flowers are reacting to light or temperature changes. Day lilies and other flowers that open and close, use cells to change the positioning of their petals.
The flowers grow brand new cells on the inside of the petals to open the blossoms. Cells grown on the outside of the petals are used to close the blossoms up again.
Some flowers expand and contract existing cells that were already formed in the plant’s past to open or close their blossoms. Heat makes the inner surfaces of a flower’s petal grow. So, when the temperature goes down, the outer surfaces grow faster than the inner ones, thus making the flower close.
The crocus and morning glory, for example, open as the temperature increases during the day and close as the day gets cooler in the late afternoon. Four o’clocks, however, close in the morning and open again late in the afternoon, around four o’clock.
We don’t know definitively why flowers close at night. There are, however, two main theories, both of which have to do with the preservation of reproductive organs and protection from weather. Certain types of plants contain a mechanism called nyctinasty that allows them to open in the day and close at night. This mechanism is affected by light intensity, humidity and temperature. Researchers have also found that flowers and plants have their own circadian rhythm (internal clock) that triggers the opening and closing.
The first theory is that flowers close at night to conserve energy for pollination during the day, when the pollinating insects are most active. The second theory is that a flower closes its petals to protect its pollen from getting wet from dew. Dry, sticky pollen is more easily transferred to insects, improving the plant’s reproduction prospects.
It is interesting to note that other flowers only open at night and close in the morning. The moonflower and the night-blooming cereus, are two such examples. Whatever the scientific reason, it is another fascinating aspect of the plants that we use to enhance our landscapes and lives.
Happy Gardening!