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The ideal conditions to grow marijuana - LIST

Discussion in 'Absolute Beginners' started by Andronius, Aug 16, 2009.

  1. I found this on my computer from a few years back, not sure where I got it, but it is really good beginner info. I know a lot of this is listed all over GC, but this has just about every thing a beginner needs in one spot.


    CLIMATE TEMPERATURE RANGE: During lights-on cycle, between 70 and 80 degrees Fahrenheit. During lights-off cycle, between 64 and 71 degrees Fahrenheit. Ideal day cycle growing temperature without C02 augmentation: 73 degrees Fahrennheit/23 degrees Centigrade. Ideal day cycle temperature with C02 augmentation: 76 degrees Fahrenheit/24.5 degrees Centigrade. (Centigrade is the same as Celsius).

    ROOT ZONE TEMPERATURE: 67 degrees Fahrenheit/20 degrees Centigrade. Growers with plants in pots growing in basements or cement slabs should not put their pots directly on the floor, as this can cool the root zone.

    WATER/NUTRIENT SOLUTION TEMPERATURE: 65 to 70 degrees Fahrenheit.

    40 to 65% during vegetative phase; 40 to 60% during flowering. Excess humidity creates conditions that allow mold and other harmful organisms to flourish.

    LIGHT CYCLES: Vegetative Growth: 18 hours on, 6 hours off. Floral triggering and growth: 12 hours on, 12 hours off. (May vary due to type of marijuana being grown and other factors).

    TYPES OF LIGHTING: For clones- Fluorescent lighting. Vegetative Growth: Metal halide and High Pressure Sodium, augmented by vertical fluorescents for side growth. Preferred vegetative growth lighting ratio: 60% Halide, 40% HPS. Lighting for Floral Growth: High Pressure Sodium.

    Stationary lights: One 400 watt bulb provides adequate light for 10 square feet of space. One 1000 watt light provides adequate light for 20 square feet of space. The use of light movers can extend these coverage areas.

    Light is measured in lumens, using a lumens meter, which is a handheld device that responds to light in a fashion similar to how a cameras light meter responds to light. The top of the plant canopy should be receiving 3000 lumens. Use the light meter and visual inspection to determine where inadequate light levels are occurring. Usually, these low light areas will be in corners, and at the bottom of plant canopies. Unequal lighting will result in unequal growth patterns, and loss of yield.

    Mylar or white glossy plastic on all walls. Aluminum foil, mirrors, and white paint do not have adequate degrees of reflectivity.

    DISTANCE OF PLANT TOPS TO LIGHTS: Metal Halide and High Pressure Sodium bulbs, if not separated from plants by glass or other material between bulb and plants, should be 2.5 feet from top of plant to bottom of light. Fluorescent or glass-shielded MH/HPS: one foot (Monitor temperature at leaf zone to prevent burning; temperature at leaf zone should not exceed 84 degrees Fahrenheit).

    STERILE GROW MEDIA: Rockwool, processed coconut husks, lava rocks, vermiculite, perlite, clay pellets.

    SOIL MIX: Organic, high-nitrogen, well-aerated, with perlite and vermiculite.

    ATMOSPHERIC REQUIREMENTS: Plants need large amounts of oxygen, especially at the root zone. They need large amounts of carbon dioxide (C02), especially at underside of leaves. Total room C02 should be 1500 parts per million, but natural levels of C02 are approximately 400 ppm, so C02 augmentation is recommended, especially in above average temperatures. C02 emitter should be timed in relation to exhaust fan so that C02 is not sucked out of room.

    Circulation by at least one medium size oscillating fan for any size grow space, no matter how small. For larger grow spaces, at least one medium size oscillating fan for every three 1000 watt lights. You should be able to feel air movement in your grow space at plant level so that all plants are in a moving ocean of air.

    Install exhaust fan sufficient to totally exchange all air in grow space every five minutes. Exhaust fans must be timed relevant to C02 augmentation to avoid removing augmented C02 from room.

    LENGTH OF GROWING SEASONS FOR MOST STRAINS OF MARIJUANA: Seed-grown plants- seven to nine weeks in vegetative growth. From clone: two to five weeks in vegetative growth. Flowering cycle: four to ten weeks, depending on strain and conditions. Some pure Sativas can take as long as 16 weeks in flowering before they are ready for harvest. Some growers begin to flower clones using 12 hour daylength as soon as the clones are rooted.

    Floral cycle begins when you trigger flowering by changing light cycle to 12 hours on 12 hours off. After this change, plants should show gender within two weeks. Important note: during the dark cycle, do not let any stray light enter the growing chamber, unless you use a low-wattage green-colored light bulb for short periods of time for necessary chamber illumination. Stray light can confuse plants and cause mutations in flowers or delay flower maturation.

    DETECTING MALE PLANTS AND FEMALE PLANTS: In most strains of marijuana, male plants grow faster and taller, with more length between leaf nodes, compared to female plants. After flowering is triggered by initiating the 12 hour on/12 hour off light cycle, and in some cases even before the 12-12 light cycle is used, male and female plants can be differentiated by examining floral growth at the intersections where the main stalk joins with auxiliary stems. This examination is best done with a magnifying device, such as a photographers loupe.

    Initially, floral growth is vaguely defined; even new leaf shoots can resemble primordial male or female flowers. As plants become firmly entrenched in floral phase, however, floral growth appears as small ovoids, larger at the bottom than at the top, located at the junction where the main stalk joins with auxiliary stalks and stems.

    Male flowers will develop a similar ovoid with an opened top, and eventually will display five-petaled flower from which pollen sacks hang. The pollen sacks are shaped like small tubes. The total size of the flower is about one eighth inch in diameter.

    Female flowers initially look like a primitive male flower, but differentiate themselves by sending up two white, pink or yellowish hairs, known as pistils.

    Some plants develop hermaphroditic flower patterns. This includes the presence of partially or fully developed male and female flowers on the same plant, as well as primarily female flowers that contain small invasions of male flower development, especially pollen sacks. Hermaphroditic plants develop due to strain variations, as well as stress. They can fertilize themselves. Seeds from hermaphroditic plants tend to produce mostly female offspring, but these offspring tend towards hermaphroditism.


    IDEAL pH OF SOIL: 6.5.

    IDEAL PPM (parts per million) OF HYDROPONIC NUTRIENT SOLUTION: For rooted clones, established seedlings, or mature plants in vegetative and flowering phase, between 1000 ppm to 2000 ppm, depending on strain, grow media, and plants growth phase.


    1. Measure total space.
    2. Ensure adequate electrical supply, wiring, outlets and fuse infrastructure.
    3. Sterilize with Wipe Out.
    4. Install venting, fans, odor filters or devices.
    5. Cover room walls and ceiling in Mylar or white glossy plastic.
    6. Cover floor with thick waterproof tarpaulin.
    7. Install lighting and timers.
    8. Install grow system.
    9. Install security system.
    10. Install plants.

    1. Bucket, hand-watered (simple, most affordable)
    2. NFT- Nutrient Film Technique
    3. Aeroponic- (requires significant hardware and expertise, uses no grow medium)
    4. Ebb and Flow- (relatively simple and the most popular, uses grow medium such as rockwool, along with reservoir and pump)
    5. Sea of Green (planting of many clones close together)
    6. SCROG (screen of green, which uses netting to support closely-packed plants)
  2. bumpdigity
  3. this is great. I vote sticky
  4. Thank you! Just wrote Ideal Temps and RH's down on a post-it thanks to you. ;)

    Have a nice weekend mate.
  5. OK for indoor newbies.
  6. My apologies your majesty for not posting a better general 'ideal conditions' post.
  7. Apology accepted - you cheeky boy!! I should spank you.
  8. Haha Srsly ^^
  9. It's a good list and helpful but there are some arguable points. Like the fact that 24/0 light cycles during veg work great and might help with shorter, bushier plants. Very important for a stealthy indoor grow.

    Just saying. ;)
  10. There are many different ways to grow, but this list is something I would have loved to read before I started.

    Most of it I've already figured out but this would have really helped.
  11. More Lumens More Lumens!
  12. rosenthal says 27-30 C
    im going to aim for 28, you can always use a 2 dollar thermostat switch for the fan.

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