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1.4: The Experiment

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    Materials (per group)

    • 6 bottles, label with group name, date, time, solution type: -P, -N, -K, -Fe, -Mg, or C for control, and a number (1-6)
    • 24 seeds (Wisconsin fast plants, Brassica rapa)
    • Vermiculite
    • Planting medium (recommend coco coir or other nutrient-free medium)


    Planting seeds. Make 6 of the following bottle growing systems (BGS)

    Figure \(\PageIndex{1}\): Bottle Growing System
    1. Put your wick (a strip of felt) through the hole in the cap. The wick should be 1/2 inch from the bottom of the bottle.
    2. Layer approximately 1/4 cup of vermiculite into the funnel portion of the BGS.
    3. Layer approximately 1/2 cup of your planting medium on top of the vermiculite so that it fills the funnel to the rim. Tap the funnel to help the soil settle loosely, then level off the excess. Do not press or compact the planting medium.
    4. Gently soak the soil and vermiculite with tap water, letting it percolate through the soil until it drips from the wick at the bottom of the growing funnel. It is important to go slowly, or planting medium can splash out. This is called the run-off. The layer of planting medium should shrink down in the funnel about 0.5 - 1 cm from the rim.
    5. Uniformly distribute 2*Fast Plants seeds on the surface of the moist planting medium around the perimeter of the funnel about 5 mm from the clear wall. *Seed arrangement may change, depending on the number of seeds available.
    6. Cover the seeds and planting medium with a layer of vermiculite (1 cm) so that the vermiculite is level with the rim of the growing funnel.
    7. Gently moisten the vermiculite with tap water until water again drips from the wick at the base of the funnel.
    8. Pour off the water remaining in the reservoir, replace it with the liquid fertilizer (-P, -N, -K, -Fe, -Mg, or C). about 2 inches from the bottom – be sure that the wick is at least 1/2 inch into the fertilizer.
    9. Clearly label each bottle of the six with the name of your group and which fertilizer solution you are using.
    10. Place all BGS in the light rack in the back of the botany lab. Keep light on 24 hours a day.

    Procedure: Weekly Data Collection

    Each week replenish your fertilizer solutions in the appropriate BGS. You may also need to stake your plants to help support them and adjust the height of the lights. Try to keep your plant tops approximately 10 cm from the light, if possible.

    Keep a log of your activities with the plants:

    • Did all of your seeds germinate?
    • Dates plants are lowered from light source or any other changes are made
    • Date, type, and amount of fertilizer added
    • Any observed differences in the plants within each BGS. Here are some examples
      • Color changes (which colors and where on the plant)
      • Growth patterns
      • Flower production
      • Leaf production (#, color, shape, etc...)
      • Patterns of chlorosis or necrosis

    Contributors and Attributions

    This page titled 1.4: The Experiment is shared under a CC BY-NC license and was authored, remixed, and/or curated by Maria Morrow (ASCCC Open Educational Resources Initiative) .

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