Plants growing in the dark science projects

Updated November 21, 2016

Science projects that involve plants growing in the dark let you grow plants in a way that they are not used to growing. Some people would say that plants cannot grow in the dark because they need sunlight to receive important chemicals that help the plant grow. People who have done growing-in-the-dark experiments may say otherwise. To find out the effects of growing plants in the dark, you can try a few experiments that will help to answer your questions.

Sunlight Absorption

This experiment will show you how important water and sunlight are to helping a plant grow to its fullest potential. To do this experiment, place soil into two plant pots and leave an inch or so from the top of the surface of the soil and the top of the pot. Place a few seeds into each pot. Give one of the plants a good soaking in water and set it on the window sill, where it can soak up the sunshine. Do not add water to the other plant and place it into a dark cupboard. Watch what happens to each plant over the course of a couple of weeks.

Seed Germination

This experiment will let you observe the effects of germinating seeds in the light and in the dark. Separate a few bean seeds into two groups and wrap each group in a damp paper towel. Place each paper towel in a separate zip-locked sandwich bag. Close the sandwich bags 3/4 of the way. Wrap one of the bags in foil so that no light will enter the bag. Place both of the bags under a desk lamp and check the bags in seven days to find the effects of germinating seeds in the light and darkness.

Full-Grown Plants

You can do experiments on fully grown plants to test the effects of darkness. Testing fully grown plants is usually easier than testing seeds because you can see results much faster, and the fully grown plants do not need as much care as the plant seeds. To do this experiment, gather four fully grown plants of the same kind and age, and separate them into two groups of two. Take one of the groups and leave it in the sunlight. Place the other group of plants inside a dark closet. After seven days have passed, check the two groups of plants and observe the differences between the plants that had sunlight and the plants that were in the dark.

Do Plants Grow Toward the Light?

Some people have attributed the way plants seem to reach for the sun as they grow to the plants' growing toward sunlight. This can be proven either way by growing a plant or two in the dark to see which direction the plant begins to grow. Place two young plants that have already sprouted into a dark closet and give them everything else they need to grow besides light. After seven days, check the plants to see in which direction the sprouts and roots grew without the light to guide them.

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