Vegetative Growth
Marijuana Horticulture
by Jorge Cervantes
Vegetative growth is maintained by giving plants 16-24 hours of light every day. As the plant matures, the roots take on specialized functions. The center and old, mature portions contain a water transport system and may also store food. The tips of the roots produce elongating cells that continue to push farther and farther into the soil in search of more water and food. The single-celled root hairs are the parts of the root that actually absorb water and nutrients. Without water, frail root hairs will dry up and die. They are very delicate and are easily damaged by light, air, and klutzy hands of moved or exposed. Extreme care must be exercised during transplanting.
Like the roots, the stem grows thru elongation, also producing new buds along the stem. The central or terminal bud carries growth upward; side or lateral buds turn into branches or leaves. The stem functions by transmitting water and nutrients from the delicate rot hairs to the growing buds, leaves, and flowers. Sugars and starches manufactured in the leaves are distributed through the plant via the stem. This fluid flow takes place near the surface of the stem. If the stem is bound too tightly by string or tie-downs, it will cut the flow of life-giving fluids, thereby strangling and killing the plant. The stem also supports the plant with stiff cellulose, located within the inner walls. Outdoors, rain and wind push a plant around, causing much stiff cellulose production to keep the plant supported upright. Indoors, with no natural wind or rain present, stiff cellulose production is minimal, so plants develop weak stems and may need to be staked up, especially during flowering.
Once the leaves expand, they start to manufacture food (carbohydrates). Chlorophyll (the substance that gives plants their green color) converts carbon dioxide (CO2) from the air, water, and light energy into carbohydrates and oxygen. This process is called photosynthesis. it requires water drawn up from the roots, through the stem, into the leaves where it encounters carbon dioxide. Tiny breathing pores called stomata are located on the underside of the leaf and funnel CO2 into contact with the water, In order for photosynthesis to occur, the leaf’s interior tissue must be kept moist. The stomata open and close to regulate the flow of moisture, preventing dehydration. Marijuana eaves are also protected from drying out by an outer skin. The stomata also permit the outflow of water vapor and waste oxygen. The stomata are very important to the plant’s well being and must be kept clean t promote vigorous growth. Dirty, clogged stomata would breathe about as well as you would with a sack over your head!