Section 10: Harvesting and drying

When you want you plants to start flowering just turn the lights down to 12 hours light and 12 hours dark. Then be patient and wait for flowering to complete. It helps the drying process a little if you don't water the week before harvesting. When you cut the plants remove the large fan leaves the and add them to your compost pile as they are not usable for smoking. Place the plants in shoe boxes or paper bags and stir them around daily. In about three weeks the buds should be totally dry and ready to smoke

Section 9: Obtaining seed

If you do want to pollinate some females to produce seed for the next crop it can be done so that only a few buds are pollinated and the rest remain as sinsemilla. First collect pollen from a male. The male should show desirable characteristics, like fast growth, potency and resistance to pest and mold. To collect the pollen just shake the branches into a plactic bag. Black paper can also be used to collect pollen. Just lie it on the floor around the plant, in a few days the paper will have quite a bit of pollen on it. The pollen can be stored in film canisters until it is needed. When needed, use a paintbrush to brush on the pollen to the LOWER branches of the female. The best way to be sure that all the seeds are mature before harvest is to just never harvest the pollinated branches. Let them die naturally so you can be sure they produce viable seed.

Section 8: Early sexing

Since you control the light cycle in an indoor operation it is easy to sex the plants early and eliminate all the males. Just turn the lights down to 12/12 when the plants are eight inches high. Use a magnifying glass to examine the flowers and eliminate all the males.
Female

Here is a female plant. Notice the white hairs.


Here is a male plant.

Section 7: C02 supplementation

Some growers add C02 to their grow rooms to increase growth rate. This has proved itself to be effective in many experiments. C02 supplementation also helps the plants withstand higher temperatures of up to 95 degrees without slowing down growth. There have been complaints however, that C02 supplementation during flowering reduces potency. Therefore, C02 should be stopped when the lights are turned to 12/12.

Section 6: Ventilation

Marijuana like all other plants puts out waste through the stomata on it's leaves. Outdoors wind, rain and sun are present to evaporate these toxins from the leaf surface. Indoors the grower must create an environment. The best way to do this is with a fan of some kind. If the grow room is large enough then an regular cooling fan can be placed inside and left on all the time. If you are running a small closet operation then just opening the door twice a day to look at them will create enough air movement for healthy growth. A fan controlled by a thermostat will also work well. These can be found at most electronics stores.

If a large number of plants are to be kept a dehumidifier may be needed. If humidity levels are too high then the chances of mold will dramatically increase. A dehumidifier will cost a grower about $100 so it isn't really practical for the closet grower.

Section 5: Sea of green

Sea of green, or SOG, is the theory of harvesting many small plants frequently, instead of large plants less frequently. In an SOG setup the closet is divided into two light tight spaces. In the top space the lights are permanently set on a 12/12 light/dark timer. On the bottom the lights are kept on for 18 hours per day. Fluorescent lights are used throughout. The bottom shelf is used to start seedlings and root clones. The top shelf is used for flowering. Using this setup harvesting can take place once a month.

Section 4: Factors affecting the rate of photosynthesis

There are other factors other than the obvious amount of light that reaches the plants that affect the rate of photosynthesis. These can be manipulated by the grower to achieve maximum speed of growth and larger yields in a shorter period of time.
Humidity

The humidity in the environment is the amount of water vapor present in the air. Most growers know that humidity in excess of 85% percent increases the probability of the appearance of bud mold. The humidity is also critical during germination when the seedlings are extremely fragile. Humidity should be kept over 80% at this stage in the plants life to prevent the soil from drying too fast. Experimentation has shown that a relative humidity of 65% to 80% increases growth rate. Below this level the plants develop extremely narrow and tissue paper thin leaves to try to prevent excess loss of water. Above 80% relative humidity the plant have trouble disposing of toxic chemicals through evaporation.
Temperture

Marijuana can survive temperatures from 32 degrees F to over 100 degrees F. Cannabis will grow best with a temperature of 70 to 75 degrees F day and night. Higher than 90 degrees F the enzymes within the plant begin to breakdown and photosynthesis is affected. The same is true for low temperatures.
Carbon dioxide

Carbon dioxide is a gas that is essential for the light reactions in all plants that carry on photosynthesis. CO2 is absorbed through the leafs stomates and is combined with water and light energy to form glucose (used by the plant as energy) and oxygen (which is released). Therefore supplementing CO2 to the existing amount in the air will speed up photosynthesis and therefore, growth will occur faster. Experimentation has also shown that CO2 can help marijuana tolerate higher temperatures (up to 95 degrees F) with little affect on the rate of photosynthesis.
Watering Marijuana

Although only a small portion of water absorbed by the plant is used in photosynthesis a shortage of water does affect the rate photosynthesis occurs. This happens because when the plant is low on water the stomates on the leaves close preventing the release of waste gases and other toxic chemicals. This closure will severely slow down or even stop photosynthesis from occurring. Over watering marijuana is very harmful to growth rate.