"Spread some lime to get rid of those grubs."
"Marigolds will keep those rabbits away." "Plant winter squash
on the third day after the full moon." "Spray beer, molasses and
ammonia on the lawn to make it healthy."
Home remedies come in all shapes and
forms. Some actually work. Others do no harm but do not work either. A few will
do a lot more harm than good. I have been answering gardening questions for over two decades and I
sometimes think I have heard them all...then the phone rings.
I have learned to not discount home
remedies out of hand. After listening to them, I always try to figure out why
the remedy would possibly work. Occasionally, there is actually a scientific
basis for at least some of the claims. Ammonia is a nitrogen source. Certain
plants either taste bad or emit chemical aromas which may repel animals or
insects. Unfortunately, there is not always a provable link between science and
the belief of the user.
The key problem with many home
remedies is that they are not tested scientifically. They are based on what is
called "anecdotal observations." Somebody’s neighbor had grubs in
their lawn. In May a couple of years ago, they spread some lime. In June, he
dug around the lawn and the grubs were gone. Therefore, the belief that lime
will get rid of grubs.
The science is that the grubs of the
European chafer transform into beetles in June. They emerge from the ground,
fly around, mate and lay their eggs in the soil and die. So, if you check for
grubs in June, you probably won’t find any whether you treated or not.
The fact that the grubs disappeared
after the lime application was only a coincidence. It was like observing that 4
people you know have been in traffic accidents during a full moon and
concluding that a full moon causes traffic accidents.
Scientists certainly do not know
everything either. However, by conducting experiments, they try to figure out a
cause and effect relationship. The key to their experiments is to control all
the factors involved in plant growth. Then, they change just one factor and see
what happens. They do this to a large number of plants to minimize the effects
of random occurrence or chance. This is extremely difficult since there are so
many factors involved in plant growth.
Many plant experiments are conducted
in greenhouses where temperature, soil, humidity, light, nutrition and other
factors can be closely controlled. The treatment being tested is applied to
half of the plants and the others are left as "controls" for
comparison purposes.
For example, say half the plants were
treated with "X" and those plants grew taller than the ones which
were not treated. Watering, temperature, soil, etc. were the same for all
plants. The experiment would be repeated several times to see if the results
can be duplicated.
Only then would it be reasonable to
say that "X" had an effect on how tall this particular plant would
grow. Even with such strict controls, the best that can be said is that
"there is a high probability" that "X" made the difference.
The results rarely show a 100% certainty of anything. Usually, a 95% certainty
of the cause and effect relationship is needed to make any recommendation.
Note: If you have any topics you would like covered in this blog, please let me know. Thanks, Mr PGC. For more information on all aspects of gardening, please visit PlantsGalore.Com.
