Agriculture Reference
In-Depth Information
How Plants Eat and Breathe
Plants “eat” primarily by photosynthesis. They break down carbon dioxide and water
and turn them into various carbon-based molecules. They need the energy from the sun,
along with proteins and minerals to make this happen. Oxygen is released during this pro-
cess, which allows us to hang around this planet.
So they need carbon dioxide, water, proteins, minerals and Mr. Golden Sun. Interest-
ingly, plants are composed of about 95% carbon, oxygen and hydrogen, so the proteins and
minerals are only a small, but vital part. This photosynthesis takes places in the leaves and
other green plant parts. While plants get carbon dioxide from the air, they are actually very
happy to get as much of their carbon as possible from the soil through their roots. And
while the roots are the major water and mineral harvesters, the leaves perform these func-
tions, too.
The most evident part of our job as gardeners with respect to photosynthesis is just to
make sure we put plants in the right sun exposure in the garden and make sure they have
enough water available. Then they can then get the right amount of sun, carbon dioxide and
water — all of which is 95% of what they need. This is easy enough with a little bit of
plant knowledge and a water source.
As I said earlier, even though the minerals make up only 5% of the plant, they are cru-
cial. Gardeners also have a role in making sure our soil has the right mineral balance be-
cause we are planting many things that probably wouldn't be growing there if they had the
choice. Almost any soil will support some kind of plant life, but if we are particular about
what plants we want to see, and if we want these plants to be healthy, there is usually some
work to do.
Like us, plants breathe oxygen. While only the green parts photosynthesize, all cells
breathe. The main purpose of breathing is turning those carbon-based molecules from pho-
tosynthesis into more useful forms of energy. The roots need to breathe, too, so they need
air in the soil. The organisms in the soil help make big pore spaces for this air. We cannot
sustainably create this through tilling or aerating — in fact, these ultimately do the opposite
if done too often, and we end up with compacted soil. All we can do is make sure the soil
dwellers have the tools they need to do a good job, which is what this topic is about.
