• Question: Why don't some plants do not grow in the soil?

    Asked by anon-44771 to Amelia, Clem, Izzy, Sarah on 18 Mar 2014.
    • Photo: Isabel Webb

      Isabel Webb answered on 18 Mar 2014:

      Plants need certain things in order to survive. These things are:
      Light
      Water (usually found in soil)
      Carbon dioxide
      Oxygen
      Nutrients (usually found in soil)

      Although water and nutrients are usually found in the soil, they don’t have to be. As long as the plant has water and nutrients nearby, it will be able to take them up and grow. Seeds have small store of nutrients already, which is why we can begin seed growth on something like a bit of wet tissue. Eventually you would need to move the sprouted seed into something with nutrients.

      Plants like cacti have very good roots that can dig very deep – so even though they live in sand, they can bury and search and find the things they need, even in small amounts.

      Some plants, like mistletoe, are parasites. This means that they live off something else. Mistletoe sets up home on the branches of other plants. It then digs its roots into the branch, and puts them straight into the water supply coming from the host plant. This water supply also carries nutrients. This means that the mistletoe can live straight off its host without needing soil.

    • Photo: Amelia Frizell-Armitage

      Amelia Frizell-Armitage answered on 18 Mar 2014:

      All plants need light, water, carbon dioxide and nutrients to survive.

      Light and carbon dioxide are easy to get, they come from the air. However, there are many different ways a plant can get its nutrients and water.

      Most plants get nutrients and water from soil. Some plants, called air plants, grow on other plants, usually trees. Their roots hang down from the branches of the tree and absorb all their water and nutrients from the air! Plants can also be parasitic- they bury their roots into another plant and absorb water and nutrients from the other plant (which can get very ill because of this!). Water plants have roots that dangle in the water and are able to get all their nutrients from the water as it moves past. An example of a water plant you may have grow before is water cress? The seeds of water cress will grow just on a damp paper towel.

    • Photo: anon

      anon answered on 18 Mar 2014:

      Plants like us have different tastes.

      In terms of soil, certain plants prefer certain combinations of nitrogen, potassium and phosporous.

      Lots of nutrients may be a little rich for some plants, and some nutrient -poor soils just won’t do for others.

      This is why when you go to the garden centre there are many many types of soils and composts and “plant foods” so that you can match the perfect “recipes” for the plant’s you would like to grow. These recipes will have been concocted by plant scientists! 🙂

      There are many other reasons why some plants don’t grow, such as sunlight, water or even pesky birds eating the seeds!

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