The key factor that separates plants
from animals is that plants take the energy from the sun
and, through a process called
photosynthesis,
combines certain elements together to create their own
food in the form of carbohydrates and sugars. Therefore,
we DO NOT FEED plants, they feed themselves.
What we do is provide nutrients which
must be combined with the correct amounts of sunlight,
water,
chlorophyll and heat for the plant to produce its
own food. If any one of these five factors is below the
minimum needed for photosynthesis, no growth will occur.
You cannot force growth by giving the plant more
nutrients if the light level is too low.
Fertilizers are the human way of providing nutrients to
our plants. Any product that is sold and makes a claim
that it aids plant growth is a fertilizer. According to
the law, such products must be analyzed for their
nutrient content and these contents must be listed on
the container.
At a minimum,
fertilizers must display the levels of the the three
macro-nutrients (the ones needed in the highest levels
by plants) which are
nitrogen (N),
phosphorus (P) and
potassium
(K). A bag with the numbers 15-10-20 on it
would include 15% nitrogen, 10 % phosphorus (P) in the
form of phosphate (P2O5) and 20% potassium
(K) in the form of potash (K2O).