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What Plants Need

– Posted in: Sustainable Gardening

If you are not a confident gardener, growing plants can be a bit intimidating if they don’t grow the way you think they should or if they just keep dying.  It can feel like a personal slight.  It is also very dispiriting is something that you nurture and care for lives a short feeble life. 

The good news is that there are a few basic plant needs that all plants require to varying degrees and if you get a bit of a feel for these needs, your plant will be a bit less mysterious and easier to care for. 


This is the factor that Melbourne gardeners will think of first when a plant is struggling. This is not surprising as our summer droughts can be quite stressful to many gardens.  Water is important for plants in just the same way that it is important for animals. It is the basis for all the life processes that occur in their cells.

The vast majority of garden plants get their water through their roots so it is good to have a knowledge of what the soil is like. Is the water getting through the soil to the roots? Is there enough mulch to keep it from drying out too quickly? Is water just flowing off the surface?   


This is the factor that people may be least aware of and is a big cause of garden plant deaths.  Plants need oxygen just as animals do, but they primarily get it through their roots just as they do water. The trouble is that is a plant that is in a spot with poor drainage and starts to suffer through lack of oxygen to the roots, a concerned gardener may respond by lovingly providing some extra water.  This of course makes the situation worse and the plant ends up drowning.  Good soil drainage means that water gets through the soil to the roots while allowing air to remain in the soil as well 

Carbon dioxide

This is the easy one but is so important that it is worth mentioning.  Carbon dioxide is effectively what green plants use as food, or more accurately, it’s what they use to make food. The bulk of a growing tree doesn’t come from the soil, it comes from the air! 

Happily it’s difficult to deprive a plant of carbon dioxide, which is absorbed through the foliage; it just needs the rest of the plant requirement for everything to work out well. 


Sunlight is the driver of food manufacture or photosynthesis, so all green plants need it to live.  This is all done in the leaves and different species will have adaptations to survive in particular light conditions.  Those sold as ‘indoor plants’ usually are species that naturally live on the shady floor of rainforests whereas many other species need full sun for much of the day.

Light is the factor that can vary the most within a single garden.  Before choosing a plant for a spot in your garden, have a good idea of how much sun it will get through the day and through the year, so you get one that matches the position.   


There is a range of important nutrients or minerals that plants need for healthy growth that are obtained through the roots.  Nutrients aren’t as critical as light, water and oxygen so they shouldn’t be the first thing to think of if your plant is looking sick.

Nevertheless it is worth think of if there are signs such as discolouring of the leaves or stunted growth.  Lack of nutrients is also relatively difficult to diagnose by just looking at the soil.  Clay soils will be more likely to hold their nutrients while they will more likely leach out of sandy soils.  Frequent harvesting of the plantings will also more likely deprive the soil of nutrient.  Using compost or a natural organic fertiliser is the safest way to provide a healthy level of nutrients, particularly in spring and autumn when growth is happening most.


Again, this varies greatly according to the climate the plant is adapted to.  All living things need a certain temperature level to ensure that all the processes for life can go on.

The trick is that many plants can withstand and perform well to extreme winter cold whereas many other plants will die in frosty conditions.  In England and North America this is what they refer to as hardiness. To them a hardy plant is one that can put up with low temperatures.  In Melbourne, when we think about hardy plants we expect them to be tolerant of heat and low water.  

One great thing about growing plants in gardens in Melbourne is that its cool but not freezing winters and hot summers can allow us to grow a great range of plants from all over the world.


These are just the basics, and they can take you far.  Knowing a bit about what your plant is and where it originated can also help greatly.

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