In Minnesota, the light intensity in winter is about 1/10th the intensity of
the summer. November/December are traditionally the cloudiest
months of the year.
Gardening with artificial lights adds a new
dimension to growing plants indoors. Plants
struggle to survive the low light levels, so they
are more susceptible to insect and disease
problems. Providing additional light indoors
doesn’t have to be difficult or expensive. It is
difficult to judge just how much natural light
you have available. If they aren’t getting
enough light, plants tend to grow taller and
weaker, and the leaves will be lighter in color.
They won’t have as much foliage and the inner
or lower leaves will yellow. The plants will lean toward the light that there is.
Several factors reduce the intensity of light indoors, including distance from
the source and shadows cast from other objects. The angle of the sun and
the strength of the light change from season to season, and
some plants need much more light than others.
You can use standard lamps, spotlights, under-cabinet lights, shop lights
or plant light fixtures. Just make sure they are rated for the wattage you
will be using. If you are in doubt, all new fixtures are rated and should
say on the package what type of bulbs can be used and the wattage.
In addition to individual lights, light units can be purchased or constructed.
The most common lights used for plants in the home are fluorescent
and incandescent. There are more intense forms of light available such as
halogen, sodium and metal halide but they require specialized fixtures and
are too large for most homes. Fluorescents provide good light, are the least
expensive to burn and produce the least heat. Unfortunately, full spectrum
tubes can be expensive to purchase. Incandescent lights are the least
expensive to purchase and provide good light. But they are costly to run
and produce lots of heat, so they can’t be placed close to the plants.
Incandescent bulbs will stop being manufactured in the future because
of the higher energy usage in comparison to more energy efficient
alternatives, such as compact fluorescent lamps and LED lamps.
Some governments have already passed laws that have started the
phase-out of their usage. Brazil and Venezuela started to phase them
out in 2005, and other nations are planning scheduled phase-outs:
Ireland and Switzerland in 2009, Italy in 2011,Canada in 2012,
and the U.S.between 2012 and 2014.
From the perspective of the plants, full spectrum fluorescents are the best
for home use. Plants do well with these special grow bulbs that provide all
the spectrum of light they need for good growth and blooming. But if you
aren’t growing blooming plants, full spectrum lights aren’t really necessary.
The light provided by regular fluorescents is fine for foliage plants.
Research shows a combination of one cool and one warm fluorescent
works as well as any plant light. You can always add a small fixture with
a grow bulb to encourage some blooming. There are compact fluorescent
bulbs available that fit into a standard incandescent light fixture. The
amount of time the fixtures need to be on will vary according to the
specific plants, but there are some guidelines. The closer your plants
are to the light source, the more light they will gather. Most plants
need a minimum of 12 hours of light each day. This light can be all
artificial or you can use artificial lights to supplement natural light. Plants
that need high light may require up to 16 hours of light each day.
A general rule is: for every square foot of plant, you should provide 15-20
watts of light. Your best bet is to monitor how your plant is responding. It
will tell you if it needs more light. Two 48” 40 watt fluorescent bulbs in a
fixture with a reflector will adequately light a 2’ by 4’ area when mounted
24-30” above the table or floor. Four 48” 40 watt fluorescents are better for
most germinating and early growth stages and will light a 3’ by 4’ area. The
smaller 20-watt tubes are best for confined areas such as terrariums.
A 100-watt spotlight will provide adequate light to a 2’ by 2’ area if
mounted within a foot of the plants.
10 Tips to Maintain
Tropical Plants During the Winter
1. Most true tropical plants don’t like temperatures below 50°,
so they should have been brought in before cool weather.
2. The leaves that have been happy outdoors won’t have as much
light indoors, and many will drop, but usually new leaves will
sprout immediately.
3. You can help this process by pruning the
plant back, sometimes quite hard. The vine
type plants will especially appreciate a
hard pruning.
4. Provide as much light as you can - a South
window is good. Light intensity is so low during the winter months even
low light plants will benefit from a sunny window until March. Artificial
light is also good, and can be just regular fluorescent bulbs.
5. If space is a problem rotate the plants once a week so each plant
gets its share of light.
6. The soil should be kept moist, but allowed to dry between watering.
Watering is best if you can stand the pot in a container of water until
the top of the potting mix looks moist, and then remove the
excess water from the saucer. Some plants, such as Bougainvillea,
prefer to be quite dry.
7. Don’t fertilize until just before you are putting the plant back out in May,
then use a low-nitrogen fertilizer such as Bachman’s Mighty Bloom®
at half strength in every watering for the first month.
8. Misting the top growth with plain water is a good idea. Fill the sprayer
and leave it standing next to the plant, so that the water will be the same
temperature as the air.
9. If you detect flying insects, use the yellow sticky traps; for others, use a
horticultural oil spray. Be careful not to spray oil on indoor furnishings.
If tiny dark flies appear, they are hatching in the soil, and can be
eliminated with a systemic insecticide for home use.
10. If you are away to warmer climes through much of the winter,
it is better not to save these plants.
TIPS
Planting paper white bulbs now for bloom on New Year’s Eve. Warmer
household temperatures will cause paperwhites to bloom faster.
Flowers and gifts from Bachman’s make any day a special one. When you order your flowers or gifts online, you know you’ll be getting a beautiful fresh floral arrangement from a trusted florist known for outstanding floral design, plus quality and service.
If you’re sending flowers or gifts out of town, you can rely on us to choose the best florist from either the FTD or Teleflora nationwide flower network. Florists who can be counted on to deliver the best fresh floral arrangements and gifts, even when doing a same day delivery.
