EXAMPLES OF GARDEN “MYTH”-INFORMATION



Myth #1 Companion planting improves plant growth.

Originally based on folklore and tradition companion planting has lots
of supporters. Some research done in the 1930’s used chromatography from
plant mixtures and evaluated the color patterns they made to determine
if they were a good match. (“grow roses with garlic, carrots love
tomatoes”, etc.)This has nothing to do with how a plant actually grows
or behaves in a garden. Science-based companion planting research has
shown that a mixture of varieties of plants is better than mass planting
of one type. It makes it hardier to pest attack, as many pests are
plant-specific. Match plants with similar water and nutrient needs.
Interplanting of tall and short crops so that sun-loving plants can
shelter shade plants makes sense.



Myth#2 Marigolds repel pests.

Data from reputable research shows no such affect. However they do
attract beneficial insects with may feed on pests.



Myth #3 Ants on peonies are necessary to allow the buds to open.

Nope, they are just feeding on the sticky sap produced by the buds. They
do no harm to the flowers but they may attack natural enemies that come
to feed on the nectar and pollen.



Myth#4 Watering on a sunny day will burn plants.

The premise here is that water droplets magnify the sun’s rays and burn
the leaves. Hmmm, let’s see! Do plants burn when the sun comes out
after rain? (There wouldn’t be much left in the tropics then…) Desert
farmers routinely use overhead sprinklers to cool and protect young
plants from drying out. This myth may have come from the observation of
applications of water high in dissolved salts. As the water dries, the
salts left behind can burn the leaves.



Myth#5 Vitamin B1 reduces transplant shock.

This was based on experiments in the 1930’s on detached roots that
indicated a positive affect. Multiple experiments since then on a
variety of plant species in the lab and field, all show no significant
effect of B1 treatment. Researchers from UC Farm Advisory have shown
that B1 supplements, which also containing fertilizer, are no better
than similar fertilizer products, but cost about ten times as much!



Myth#6 Gypsum will “loosen” clay soil, and raise pH.

This is true only if you have soil where sodium, instead of calcium or
magnesium, saturates the clay. In these “sodic” soils gypsum causes soil
particles to gather together, improving structure and water
infiltration. Our foothill clay is typically not “sodic”. Gypsum will
not “loosen” our soil; organic material such as compost is your best bet.

Gypsum’s makeup is calcium sulfate (CaSO4*H2O) and has no effect on pH,
but is a good source of calcium or sulfur.



Myth#7 Pruning seal helps wounds “heal”.

This was based on the premise that a covering of pruning paint or tar
protects the cut surface from decay. In reality: wood-rotting organisms
may already be in the surface, so you are just trapping them in. The
coating can crack leaving the wound even more susceptible to decay. This
coating may also actually inhibit the callus formation on the wound,
slowing the natural protective process. The bottom line - prune at the
proper time for the type of plant, make appropriate pruning cuts, and
let the tree protect itself.



Myth #8 Buy the biggest plants you can afford to get a jump on
growth.

Research has shown that a #1 can oak tree will catch up to (and often
surpass) a #5 can tree within 1 to 2 years. Ohio state research showed
that tomato seedlings that are already fruiting when transplanted yield
poorly, even if the fruits are removed.



Myth #9 If a plant is pot bound, remedy it by cutting the root
ball or teasing roots out and directing downward.

New research from the Univ. of Minnesota shows no difference between
these treatments and no treatment after 2 years.



Here are some final considerations as you evaluate the vast resources of
knowledge:

* Consider the source.
* Does other data support their conclusion?
* If there are only testimonial and no data, or appears to be more
hype than hypothesis, buyer beware!
* And lastly, make sure the data is relevant to your climate, soil,
and ecological conditions. Someone in Connecticut may be able to get by
without watering all summer by using thick mulch, but here in
California, with our dry Mediterranean summers, that probably won’t apply!


Andrew wrote:
On Dec 6, 11:32 am, "Blackadder" wrote:
Do you use the spray during the day?

I used a similar spray and it ended up burning my roses - but it was on
account of the sun's heat. If I had done it in the evening or very early
morning it doesn't happen.

BD


Pyrethrins are also quite oily which probably intensifies the problem
of spraying in hot weather.