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First Grade
New Plants
FOSS Plant Care Notes
Brassica Seeds
In the New Plants Module, brassica is used as an example of a
typical flowering plant. By providing ideal (albeit unnatural) conditions
of perfect nutrition and continuous light, students can observe
germination, leaf formation, budding, flowering, and seed development
in a few weeks rather than a few months.
This brassica is completely dependent on continuous cool light, or it
will fail to grow at all. Cool does not refer to the temperature, but
rather to the color of the light. Brassica needs light that is strong in
the blue (cold) wavelengths of light, rather than the red (warm)
wavelengths. For this reason, if you need to replace a fluorescent lamp
in the light source, specify a cool bulb.
Brassica grows best when it is kept moist and well fertilized. To do this
we suggest putting water in the tray in which the planter cups stand.
The water will soak up into the cups. Add water only after all of the
water has been soaked up (or evaporated). At that time add four
drops of liquid fertilizer to 1/2 liter of water and pour it into the tray.
The light that falls on the brassica plants should be as intense as
possible. Therefore the distance from the bulbs to the plants should be
between 3 and 7 cm (between 1"and 3")—never more than 8 cm (31/4"). As the plants grow, the lamp should be raised using the chainand-hook system. Other than that, just keep the soil moist, and you
can almost watch the plants grow.
The Brassica rapa seeds were developed at the University of Wisconsin
and are widely used in education at many levels. There is a phone hot
line in Wisconsin for teachers who are using the seeds and have
questions about their growth or need more information for extension
activities. That hot line is 1-800-462-7417. The website is
www.fastplants.org.
BULBS
Bulbs are most often found in the subterranean world along with roots,
but are not roots themselves. A bulb is a short piece of stem with a
bud at one end and roots at the other. Around the bud is a compact
capsule of modified leaves. The leaves are thick with water, sugars,
and starch. The aerial parts of the plant can die back completely at the
end of a growing season, leaving the bulb underground to nourish and
protect the bud that will produce next year's plant.
Some bulbs, like onions, garlic, and shallots, start growing whenever
moisture is provided. Others start growing only after they have been
cold for awhile and then warm up. Such a triggering mechanism is
essential to the survival of plants that live in areas that experience
hard freezes during the winter. Bulbs that normally bloom in the spring
can be induced to start their growth early, providing bright, fragrant
flowers in the dead of winter. Fooling bulbs into growing early by
putting them in the refrigerator for a few weeks in the fall is called
forcing and is a common practice with hyacinths, tulips, and daffodils
and their relatives.