To grow great plants, one should understand their life cycle which includes the the vegetative, reproductive, senescence, and dormancy stages.
First, most plants start as seeds. Many people know this, but what they don't know is that seeds are actually immature plants protected by hard shells. The shells contain all the food plants need for the earliest part of life stored in an area called the endosperm. Under the right conditions, these immature plants can bust out of their shells and start growing.
In order for this to happen, the seeds need to be germinated. Although you could simply drop seeds in small rockwool cubes or rapid rooter grow plugs, you'll have greater success if you germinate them first. One way to do this is to place your seeds between some moist paper towels and place them in a dark, humid environment.
If done properly, after a few days you'll see what's called the taproot poking out of the shells. In order to give your new plants the best chance possible to thrive, you would place your germinated seeds into your grow medium, taproot pointing down. This simply reduces stress on your baby plants as the taproot is the part that's going to start digging downward, looking for water.
While the taproot digs downward, the shoot (stem) of the seedling starts stretching upward searching for light.
At this point, the plants are using their stored up food for growth (remember the endosperm). However, these reserves will soon be depleted and the plants will need to create their own food. This is only possible after the plants grow leaves.
The leaves contain a chemical called chlorophyll which gives plants their green color and it's what makes it possible for plants to collect energy from the Sun. Next, the plants use this energy to convert carbon dioxide and water into sugars and other carbohydrates. This chemical process is called photosynthesis.
This stage of development, where the plants are developing roots, root hairs, and leaves, is called the vegetative period. One way to know you have a healthy plant is to observe the roots. They're easiest to see in a deep water culture hydroponics system and they should be bright white and very strong.
Next, is the reproductive stage. During this time, plants will form flowers that are either male, female, or both (hermaphrodite).
These flowers contain pollen and eggs that, when combined with the pollen and eggs from other flowers, will become seeds. The pollen is spread in various ways such as wind, insects, animals, or people.
After the reproductive stage, plants enter the senescence period of their lives. Senescence is another word for biological aging which is the change in the biology of an organism as it ages after reaching maturity. This change can been observed in the Fall when leaves change colors and fall off.
Continuing, some plants enter a fourth stage of life called dormancy. Dormancy is similar to hibernation in animals in that certain metabolic functions are slowed. This allows plants to survive the cold of the winter months. When the warmth of Spring returns, plants once again start sprouting leaves. Since they don't have to start all the way from the seed stage, they have an advantage over other plants because they're bigger. Being bigger means it's easier to suck up lots of sunlight and nutrients. This cycle continues over and over until the plant eventually dies.
In nature, the stages of plants' lives are dictated by the amount of sunshine they receive. However, indoor gardeners control how much light their plants get and therefore are able to control exactly when a plant goes from the vegetative stage to the reproductive period.
Understanding the vegetative, reproductive, senescence, and dormancy stages will give you more insight into exactly what plants need so you can grow the best ones possible.
