University of Vermont Extension
Department of Plant and Soil Science
Winter News
Article
WINDOWSILL
HERB GARDENING
Dr. Leonard Perry, Extension
Professor
University of Vermont
An
indoor kitchen herb garden will add flavor to your meals and color
to your window
sills...and help satisfy that gardening desire during the cold,
wintry months.
Most
culinary herbs require at least five hours of sun per day. You can
use a sunny
window, provided the reflected heat is not too intense. If you don't
have a
window with direct sunlight, put your pots of herbs in a spot with
plenty of
light, then move them into the sun for a few hours whenever
possible. Winter is a good time to start herbs as the
sun is getting brighter and the days longer as the plants grow.
Fluorescent
lights, or special grow lamps, also work if left on about 14 to 16
hours per
day. Place the lights 6 to 12 inches above the tops of the plants,
if possible.
If the light source is too far away, insufficient light will reach
the plants,
and they won't grow. If using
fluorescent lights, alternate warm and cool white bulbs in the tube
fixture, or
use ones listed for “natural” light. If you
just have a pot of herbs or two, you can use a spot lamp near them.
You
must also consider temperature and humidity. Most herbs need daytime
temperatures of 68 to 70 degrees F with 30 to 50 percent humidity.
To increase
humidity, place a dish of water near the plants, or place the pots
on a tray of
pebbles you keep moist.
Pot
your herbs in a mix of vermiculite or equal parts peat moss, garden
loam, and
coarse sand. Or buy a
potting mix with such ingredients, but not the heavy garden loam.
The potting mix should be
slightly moist before sowing. Any container will do, as long as it
has good drainage. You may want to start seedlings in a small
flat or pot, then transplant as they grow.
Sow the seeds according to the package directions, but no deeper
than two
times the diameter of the seed.
After
planting, lightly water with the spray nozzle on a sink, or mister.
Place
each container inside a plastic bag to create a "greenhouse,"
leaving
the top slightly open to allow some air and moisture to escape. Set
in a fairly
warm location (65 to 75 degrees F) out of direct sunlight until
seeds
germinate. Don’t place on a wood stove
or too near, as the soil may stay too warm.
If near forced air heat vents, check often as this can dry out the
soil
and seeds.
Germination
should start in two to three weeks. At that time, remove the
plastic, and move
the container to a cooler area (60 to 70 degrees F) where it will
receive good
light but not direct sun, unless for only a few hours in the day.
Gradually
increase the amount of sunlight if possible, and rotate pots for
even exposure
to sunlight. Continue to water, but don't overdo it or the plants
may rot.
Thin
your herbs when the seedlings have two sets of true leaves. If you
started
herbs in flats, this is the time to transplant them to individual
pots. Use a similar
potting medium as used for germination, or as for potting
houseplants.
Herbs generally need little fertilizer, but
will respond to some. Use a soluble liquid or dry fertilizer, and
apply at half
strength based on label directions. Liquid seaweed works well on
many. Over-fertilized plants often have a poorer
flavor than those grown at a more moderate rate.
Potential
problems growing herbs indoors are pests that you don’t see
outdoors, due to
natural predators there and the rain washing them off. You can
simulate the latter by regular gentle
showers or baths for your mature plants.
If you wash them in soapy water, make sure it is quite dilute,
otherwise
the soap may injure the leaves. If using
organic sprays such as insecticidal soaps, make sure to read the
label and
check if herbs and edible plants are listed.
Watch, in particular, for aphids and spider mites.
Some
easy-to-grow annual herbs that can be transplanted to your garden
next spring
include basil, parsley, dill, oregano, chives, coriander, tarragon,
and anise. I like to have a pot of mint handy for adding
to peas (English style serving), or hot tea.
Mint, of course, is a vigorously spreading garden perennial that you
may
want to keep in a pot next summer.
Some
herbs are more commonly started from cuttings, so if you didn’t do
so last
season, you may want to look for these are garden stores or in
catalogs. Bay is a woody plant that does well in
containers year round, and of course its leaves are common in
Italian sauces as
is thyme—another one to look for as a plant.
Rosemary is another woody plant, growing as a shrub in hot and
Mediterranean climates. Yet I find it
will tolerate cool, but non-freezing, conditions.
If
planting your herbs outdoors this spring after frost, or starting an
herb
garden this summer, mark your calendar now to dig some plants next
fall to
bring indoors before frost for next year’s indoor herb garden.
Return to
Perry's Perennial
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