Hardware Reference
In-Depth Information
Check on Your Plants
HACK 38
Plants are an important part of the ecosystem of life on our planet. Or
maybe you just want tasty toppings on your burger. Either way, you can
use your Raspberry Pi to help them grow big and healthy.
Gardening is tricky stuff. Plants can't talk, so they can't tell us what they need. Gar-
deners are like hackers in a lot of ways: they learn a lot by doing, getting experience
in how to grow plants, where to keep them, how much to feed them, and what songs
they like to listen to (hey, I heard they love music). At the heart of this, whether they
realize this or not, is data gathering. By adding a dedicated temperature and humidity
sensor to a Raspberry Pi, we can gather useful data about the state of the garden.
Most plants need a few things to grow properly:
Soil
This supports the plant and gives it an anchor for the roots to grow in. The roots
draw in the water and minerals that the plant needs. You want to use a healthy,
well-nourished soil with the right sort of minerals and ingredients for your plant.
Potting soil is usually a good start, but there are much larger topics about getting
the perfect soil for your plant.
Sunlight
Plants perform
photosynthesis
, which is the process of converting sunlight into
the chemical fuels to “power” the plants biological processes. All green plants
need light, but the amount varies by plant. Some plants prefer a lot of of light, and
some plants prefer much less.
Air
Specifically, carbon dioxide. If the air near your plant is too polluted, your plant
will not grow well.
Water
Everything alive (that we know of) needs water. Plants are no different, but the
amount of water that a plant requires varies by the type of plant. If this is confusing
to you, think about a cactus in the desert and then compare it to a palm tree next
to an oasis. Both are plants, both need water, but the cactus needs far less to
survive (and wouldn't really be able to use more than a little anyway).
Space
Plants need space to grow, usually up, but sometimes outward.
Optimum temperature
Again, this is specific to the type of plants, but all plants have a range of temper-
atures that they prefer. The U.S. Department of Agriculture calls this “plant har-
diness” and maps it out into zones across the United States. Each zone is indi-
