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Ask the Ecologist:
by Belle Bergner
Q: I grow vegetables and herbs in pots
on my deck and last year some of my
herbs did not do as well as my tomatoes
and peppers. I watered them all the
same amount and kept the soil moist.
Any idea what could have happened so
that I don’t do the same thing again this
year?
A: I’m afraid the answer might be right
there in your question – you probably
watered the herbs too much. This would
be unusual for container gardens;
typically, potted plants dry out much
more quickly than people can remember
to water them. It is important to know
that most plants need their soil to dry
out at least partially. Otherwise, roots
may start to rot as soil micro-organisms
out-compete the plant for nutrients or a
mold or fungus may decay the roots.
Good drainage is essential. Check for
the drainage hole(s) at the bottom
of your pot before you fill it up with
dirt. Make sure the drainage holes are
unobstructed. You may want to add an
inch of gravel to the bottom of large
containers to aid in drainage – this also
serves to add stability. Any pot with
a drainage hole in the bottom needs
a saucer underneath to help keep in
moisture.
Your choice of container will affect your
plants’ growth too. Clay or terra cotta
pots dry out more quickly than plastic
because they are more porous. You’ll
have to water them more frequently
than plastic, but in your case, this may
be just what you need.
Please don’t start under-watering now
that I’ve made you paranoid about
watering too much! Just make sure the
top of the soil is dry to the touch before
you water each pot. Each plant will have
different water uptake capabilities.
There may be some other things to
consider in your case, or in our other
readers’ cases: check off each item on
the list below to be sure your container
garden will be healthy this year.
• Make sure herbs and veggies get at
least a few (3) hours of direct sunlight
and some partial sun / shade. The more
direct sun you get, the quicker the soil
will dry out.
• Dark colored pots get hot and might
make living conditions tough for the
roots - especially if you get a lot of
direct sun. Green is best.
• Make sure the container is big enough
to allow root growth. Check the plant
tag to get an idea of the plant’s mature
size before planting. If in doubt, get a
larger pot. A pot should also be heavy
enough to resist wind.
• Good soil is essential. Fill the container
with good quality potting soil (light,
not too dense) up to an inch from the
rim – any more soil will wash out when
you water.
• Fertilize with either your compost,
Milorganite™, a slow-release capsule
fertilizer, or a dilute mixture of equal
parts nitrogen – phosphorus – potassium
(N-P-K). If you choose the latter, you’ll
need to fertilize a few times during the
season because potted plants leach
nutrients faster than those planted
in the ground. Too much fertilizer
can burn the roots too.
If you continue to have problems, bring
your plant to Kellner’s Greenhouses on
Humboldt Avenue for Paulette’s special
advice.
Send your ecological inquiries to our
resident ecologist at bergnerb@gmail.com
Riverwest Currents online edition - May, 2007 |