Seasons and Cycles:
Indoor Bulb Experiments

Part 2

Putting Bulbs into Cold Storage

Test your refrigerator temperatures

You can experiment with cold storage temperatures using any available refrigerator or cold room. Refrigerators commonly operate between 34-44 F. Test yours by placing thermometers in several different locations. If the temperature varies significantly you may want to devise experiments with the results.
Pots of bulbs can be placed outside in colder climates (covered with various types of insulation), then brought in after different periods of time.
During the cooling period, keep the soil moist but not wet. Keep the pots cool and never allow them to freeze.

Bringing Bulbs Out of Cold Storage
Different bulbs require different amounts of cold before they will grow. Think about your own gardens- the earliest bulbs are often wildflower bulbs or domestic “Snowdrops" or crocus. As the spring season advances, later bulbs emerge according to their own inner clocks.
Although most bulbs need between 12 and 16 weeks of cold to break their dormancy, you might design your experiment to look at this phenomenon.
Generally, when the bulbs have sprouts of about 3 to 7 cm, the pots will be ready to bring out into your warm classroom. Place them at room temperature in a bright place for all to enjoy.

Digging Deeper
1. Exploring Growing Degree Days
  • How much heat does it take for your bulbs to grow and bloom? Try using the "Growing Degree Day" lesson indoors.
  • Predict GDD values for both your indoor bulbs and your Red Emperor tulips planted outside. Which will require more heat?

2. Try Forcing Paperwhites: Don't have a cold place to force bulbs?
Try this:

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