Do plants really need warmth to grow?

The bean test: what "soil" do plants need to grow?

April 18, 2016 Research & Discover, Plants

You will need the following things for the experiment:

  • 4 plant containers, for example water glasses
  • Different materials as a substrate: gravel, sand, soil from the bed in the garden or potting soil from the hardware store, cotton wool
  • 8-12 uncooked beans. You can find them in the supermarket or in the health food store, for example.

Fill each jar with one of the materials. If you want, you can write a little sticky note on the glasses. Then you know at first glance what is in which glass. Make two to three small holes in the material, depending on the size of the glass.

You can use a pencil to make the holes. Depending on the material, it works differently to form holes. You can also make small hollows in the cotton wool or gravel. Then you put a bean in each hole and cover it with the material from which the subsurface is made.

Tip: If you make the holes on the edge of the glass, you can watch the beans grow later!

Finally, you pour the beans. Pour enough water into the containers so that the contents are moist, but do not create puddles on the surface. The material should stay moist from now on. So make sure to water the beans regularly!

Place the glasses on the windowsill or in a place that is light and warm.

What is happening now

In the coming days and weeks you should watch what happens in the glasses. Check back every day to see if you can see any changes. After only three days, something should happen. So that you can easily compare the observations later, it is best to create a table. Put a line there for each material. There you can enter what happens every day. Is the bean changing? Can you see anything above the surface? If yes, what?

You can also do the experiment in school! Maybe you can think of more things to compare. What happens if you water so much that the plants are in the water? What if you don't water at all? You can also put a vessel in the dark. Ask your teacher if they can help you.

After a while you will notice that the bean plants grow differently in the containers. Now it's time to find out why. Think carefully about what's in the different materials! At ÖkoLeo there is a lot of information about the soil. You can use search to find them. Or read why the United Nations even declared a "Year of the Soil".

The "real" soil on which plants grow well in nature also depends on the needs of the plant! Soil consists of mineral grains, humus, water and air. Wheat, for example, needs a loamy, humus-rich soil with many nutrients. It has to be quite loose and store water well between the crumbs of the soil. Other plants grow better under completely different conditions - you surely know, for example, what a cactus needs?

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