Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

last chance you will have to use sprays to combat them.
March 15th, Eleventh Week
    Tops elongate, making the garden’s profile about 6-12 inches taller than two weeks ago.
    Continue fertilizing with a high-bloom fertilizer.
    Older leaves may start to drop a little faster, due to decreased nitrogen in the super-bloom fertilizer or if only an HP sodium lamp is used.
    Inspect for bud (gray) mold.
    Check all factors listed on the checklist.
    Buds should be oozing with resin by now.
    Some shade-leaf yellowing is normal.
    Indica and early-maturing buds are nearly ripe now. Harvest if ready.
    Water as needed.
    No insecticides!
    No fungicides!
    No fertilizer!
    Check for bud blight or bud mold.
Fourth Month
April 1st, Twelfth week
    The only change will be in growth of more and heavier calyxes on the flower buds.
    Continue to water as needed.
    Bud (gray) mold could become a problem. Constant scrutiny is a must! It shows up overnight, so watch out!
    Everything should be ready for harvest by now. If it is not, consider growing an earlier-maturing strain of cannabis.
    Harvest now or within a couple of weeks.
    THC content is on its way downhill when resin glands turn amber.
    Let “seed crops” go until the seeds are big and healthy before harvesting.
    Harvest and clean up.
    Move in rooted clones for next crop.

This big ‘Kahuna’ will be ready soon.

Huge buds adorn this garden a week from harvest.

Mouth-watering ‘S.A.G.E’

CHAPTER NINE
LIGHT, LAMPS & ELECTRICITY

    A single handle raises and lowers an entire room full of lights!

This graph shows the exact level at which A. Phototropic response, B. Photosynthetic response, and C. Chlorophyll synthesis take place.

The single humped line in the center of the graph represents the visible light spectrum humans see. The dual humped line represents the spectrum cannabis needs to grow.

Introduction
Light, Spectrum, and Photoperiod
    Marijuana needs light to grow. The light must have the proper spectrum and intensity to ensure rapid growth. Light is comprised of separate bands of colors. Each color in the spectrum sends the plant a separate signal. Each color in the spectrum promotes a different type of growth.
PAR and Light Spectrum
    Plants need and use only certain portions of the light spectrum. The most important colors in the spectrum for maximum chlorophyll production and photosynthetic response are in the blue and red range. The main portion of light used by plants is between 400 and 700 nanometers (nm). * This region is called the Photosynthetically Active Radiation (PAR) zone. **
    “PAR watts” is the measure of the actual amount of specific photons a plant needs to grow. Photons are a measure of light energy. Light energy is radiated and assimilated in photons. Photosynthesis is necessary for plants to grow and is activated by the assimilation of photons. Blue photons are worth more PAR watts than red photons, but scientists have difficulty measuring the exact difference.
     
----
    * One nanometer (nm) = one billionth (10 -9 ) of a meter. Light is measured in wavelengths; the wavelengths are measured in nanometers.
    ** Some scientists still disagree as to the exact PAR zone and make their calculations based on 350 to 750 nanometers. PAR watts measured with this scale will be a little higher.
----
     

    Each color of light activates different plant functions. Positive tropism, the plant’s ability to orient leaves toward light, is controlled by spectrum. Light bulbs deliver only a part of the necessary light marijuana needs to grow. However, they deliver enough! Most of marijuana’s light needs can be met by artificial means.
Measuring Light
    Virtually all light is measured in foot-candles, lux, or lumens. Foot-candles and lux measure light visible to the human eye. The human eye sees much less of the light spectrum than plants “see.” The eye is most sensitive to light between 525-625 nanometers. The importance of the blue and red portions in the spectrum is diminished greatly when light is measured in foot-candles, lux, or lumens. A foot-candle is a unit of illumination equal to the intensity of one candle at a distance of one foot. The lux scale is similar to that of the foot-candle; one foot-candle is equal to 10.76 lux.

Although this simple light meter measures light in foot-candles rather than PAR, it still gives an accurate idea of light distribution.
    Humans see light differently than plants do. Compare the graphs (page 170) to see how the light you