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Name: Sorcha
Status: student
Grade: K-3
Location: FL
Date: April 2008

Question:
Hello I would like to know why does plants need water and soil to keep them growing?



Replies:
Dear Sorcha:

Like people, plants need water to live. They use it to carry food to all parts of the leaves and stems. They need it to make their food. And they need it to get rid of their waste.

Plants need soil for a lot of reasons. They need it for their roots. Why? Because they drink, (that is take up water) using their roots. They also get chemicals from the soil through their roots. They use these chemicals and the water to grow bigger. And since plants cannot move by themselves the way animals can, they need to have a place to stay, and the soil allows that.

Hope this answers your very good question.

R. Avakian


Most plants need soil to keep their roots in place. The roots do two things. First, they anchor the plant against wind. Second, they absorb the chemicals that the plant needs to live. These two things are needed for the plants life. Plants need water because water is part of the chemical reactions that plants use to convert CO2 (carbon dioxide) into ingredients the plant needs to grow. This process also requires light, so the name of this chemical process is "photosynthesis".

Not every kind of plant needs roots. Plankton, a kind of algae, which grows in the ocean just floats around and hence no roots are needed.

Vince Calder


Hi,

A very good question - and a very important one if you are trying to grow plants.

Soil and water are a bit like the food and drink for the plant.

Water is very important, for two main reasons.

Firstly, it gives the plant a lot of its structure. Just as a balloon becomes firm and rigid when you blow it up with air, so the tiny cells that make up the leaves of the plant become firm and rigid when they are filled with water. If the water is lost, because you forgot to water the plant, then the cells start to go soft, just like the balloon would if you let the air out. What we see is that the leaves become limp and soft, and we say the plant is wilting.

Secondly, the water allows the important changes to happen in the plant, because chemicals (which come from the soil and the air) can travel around in the water. Being able to move in the water is very important. If you put a dry teabag in your mouth it has almost no taste. The chemicals which give the tea its flavour cannot get to your tongue. But if you make the teabag wet you can taste the tea - and it tastes even better when you use a cup and take the bag out after the favour is in the water. In the plant, the water allows the various chemicals to work together to build more cells so the plant can grow.

The soil is part of the plant's food.

Just like you, the plant needs food to grow. Unlike you, plants can make a lot of their own food, because they can use sunlight to help them make food chemicals called starches. This is a really important process. Without it, we would have no food, because we get our starch from corn and potatoes and rice (all plants). The process is called Photosynthesis. (we say FOE TOE SIN THU SIS ) and it works because of the green colour in the leaves. The green is called Chlorophyl (Say CLAW ROE FILL ) To be able to make chlorophyl and other parts of the leaves and so on, the plant needs chemicals which it can only get from the soil. And the soil also helps to hold the plant up. Plants and trees use the soil to hold them upright.

I apologise for the long explanation, and the big words, but you have asked a very hard question, and I have tried to give you an answer which is accurate and easy to understand - I hope I managed to do that.

Nigel
Tennant Creek
AUSTRALIA



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