• Question: Why do some plants need watering less than others?

    Asked by to Aimee, Chris, Dave, Greig, Laurence on 16 Jun 2014. This question was also asked by .
    • Photo: Greig Cowan

      Greig Cowan answered on 16 Jun 2014:

      I’m not a botanist, so I’m not sure about this. However, every plant is different and has evolved in a different environment so has adapted to survive with different levels of water.

    • Photo: Dave Jones

      Dave Jones answered on 16 Jun 2014:

      Like Greig said, it’s all about evolution. Some plants have evolved in places with loads of water so they are used to it. Put them in a dry place and they can’t survive because they are used to having so much water – their evolution has made them work best in places with lots of water. The same for plants that don’t need very much, like cacti, they have evolved to survive with very little water because they evolved to live in places like the desert.

    • Photo: Aimee Hopper

      Aimee Hopper answered on 17 Jun 2014:

      bigger plants need more water because they need more energy to grow, and water is essential in photosynthesis.

      also, some plants are used to environments where they lose a lot of their water though their leaves, or they are fruiting, or have flowers and need to produce necter, and so they also need more water.

      plants like cacti only need a small amount of water because they have perfected living on only a small amount.

    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 25 Jun 2014:

      Plants in general need to breath in air in order to absorb the CO2 they need for photosynthesis. Instead of a mouth and lungs like us, they have little holes under their leaves called ‘stomata’. Just like we can open and close our mouth, plants can open and close their stomata.

      When they open them, the CO2 comes in, but a lot of water also escapes (something similar happens in our lungs, have you ever seen condensation when you breath out on a really cold day? it makes like a cloud. that cloud is mostly water vapour escaping from your body!!). The wider the plants open their stomata, the more CO2 they can get for photosynthesis, but also the more water escapes.

      Plants in tropical regions or humid climates can have their stomata wide open all the time, because there is a lot of water available everywhere, but in dryer climates, plants don’t keep them wide open, so they lose less water.

      Some special plants called ‘succulents’ have a special adaptation to store extra water and lose even less water to evaporation. This is because these plants evolved to survived is very dry climates, or through long droughts.

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