The Roots
The magic chemistry of plant growth starts at the roots. Roots send nutrients (in exchange for sugar) up through leaf stems to the leaves for final processing. They are also large storage sites for excess energy from the leaves, which is stored as starch. The roots and their capacity to store starch will decide how well a plant will grow and how much the plant will yield.
Root size :
A research Rye plant in a 12-inch pot had 14 billion root hairs that, if placed end to end, would have stretched 6,200 miles (almost 10,000 kilometres). The root hairs alone would have covered a square area of 180 ft by 180 ft (about 55 m by 55 m) ! The more extensive the root system, the better the plant will grow. This is because roots storing much energy are able to exchange lots of nutrients up to the leaves, and so the leaves can send down more sugar, etc. Thus, root growth is directly affected by moisture, oxygen, temperature, and sugars sent down from the leaves.
Root medium is important for plant growth. The less energy the roots use to absorb water and nutrients from their surrounding medium, the more they can use that energy to grow and to help send nutrients up to the plant. Most of a plant's water is taken in by the root hairs. 99% of the water taken in by a plant is transpired out through the leaves. A plant will fall over and wilt as a result of its roots not being able to extract any more water from the surroundings.
Air roots : in a plant's natural life in the earth, its roots get moisture
from rainfall. After rain, the soil water soon sinks down and the topsoil dries quickly. For this reason, the top 1/3 of plant roots are air specialized and the bottom 1/3 are water roots. One must be careful not to keep the air specialized roots constantly wet or the plant will drown. The bottom section of roots can be constantly wet provided that the water has oxygen in it. Stagnant water will soon kill the plant. The roots should always look crisp and white. If the roots develop brown tips or general browning, the problem is usually lack of oxygen, and infection will soon follow.
A plant can function quite well with its roots exposed to light as long as they do not dry out. However, the light encourages alga growth, which causes odours, and the alga competes with the plant for nutrients in the light period and oxygen in the dark period.
Oxygen is the most important root requirement because the roots need oxygen to convert sugar to energy. The more oxygen available to the roots, the more energy they can transfer to the plant.
Temperature also affects root growth and function. The roots do a
great deal of their storage developing at night when the green sections of the plant are not being pressured by the light to produce and distribute the day's excess sugar to the roots. Roots function more efficiently when they are warm, so roots in warm dark period develop better structures than those grown in cool dark period. As an illustration, a cycle of warm dark 77°F (25°C) and day 59°F (15°C) would develop better roots than a cycle of cool dark 59°F (15°C) and day 77°F (25°C). In essence, plants will grow better with a high average 24-hour root temperature that is constant rather than fluctuating.
Supercharged roots : the root hair zone is relatively small and starts just behind the growing root cap. This zone advances with the growing roots and as the new hairs near the tip emerge, the older hairs die off. Here is where most water and nutrients are absorbed. So for supercharged growth, plant roots must not be allowed to become rootbound but be kept healthy and advancing at maximum throughout the entire life of the plant. When growing in pots that are too small, it is better to have the roots trim themselves by coating the inside of pots with a special copper paint rather than letting the roots circle and girdle themselves. In general, pots are not oxygen efficient for super plant growth. Remember that plant yield is proportional to root size
Now if you'll excuse me, it's about that time....
