In order to achieve a good harvest of numerous, large buds packed with healing medicinal properties, your plants must be taken through two phases after you have germinated the cannabis seeds: the Vegetative Stage, and the Flowering Stage. First off, let’s talk Vegetation!
The Cannabis Vegetative Stage: An Important Step in Cultivation
When it comes to cannabis – patience is a virtue.
The cannabis vegetative stage can last as little as one week, or as long as six months. For cannabis grown indoors – where it is easier to control all aspects of life – the vegetative stage generally spans four to eight weeks. Following this vital phase, the flowering stage can be induced (through a change in lighting); this secondary stage lasts between 40 and 90 days.
The length of the vegetative stage depends on the cannabis strain that has been planted. Auto-flowering varieties have a very short vegetative stage, regardless of their environment, because they are bred to automatically begin flowering after a set amount of time. Indica-dominant strains tend to grow little once the flowering stage has begun, and so may be kept in the vegetative stage a bit longer in order to support a larger harvest; sativa-dominant cannabis varieties can as much as triple in size after flowering begins, and so can support a shorter vegetative stage while producing a similar yield.
Despite this wide variance, the vegetative stage is very important. It is during this period of time that the structure and strength of stem and branches is developed. The stronger the support structure of the plant, the more weight the cannabis can sustain during the flowering stage, translating to a higher bud yield. A good, healthy vegetative stage will also directly impact the health and quality of the buds.
Maintaining the Marijuana Vegetative Stage
First and foremost: Light
Cannabis plants are held in the vegetative stage by limiting the amount of darkness to which they are exposed each day. The exception to this is auto-flowering varieties, which enter the secondary flowering stage after two or three weeks, regardless of light.
To keep cannabis plants in the vegetative stage, the hours during which the plant is in darkness must be limited. Somewhere between 18 to 24 hours of light is recommended, and the “best” method depends on the growers’ preference, or previous experience with certain strains.Cannabis will not flower as long as it has more light than darkness each day. Often the length of “daytime” will be determined by the grower’s budget: it is costly to keep high-intensity bulbs turned on 24 hours a day. Most growers use a timer to ensure their plants have a consistent ratio of light to dark throughout the vegetative stage.
The strength of the lamps used will affect the amount of growth that occurs during the vegetative stage; cannabis plants do best with lots of direct sunlight, so the more intense the light, the better the results. Indoors, blue spectrum bulbs will encourage good growth, but full-spectrum lights are suitable for the vegetative stage.
With any light, especially high-intensity, comes heat. The cannabis plants should never be allowed to grow closer than 16 inches from the lamps – two feet is ideal. The grow room itself also must not get too hot, as this can result in growth retardation during the vegetative stage, leading to a poor bud yield. During the day (hours of light), the grow room should be between 70 – 85 degrees Fahrenheit. A lower temperature of 60 – 70 degrees Fahrenheit is fine during the night (hours of darkness).
Keep these up during the Flowering Stage, too:
Though these factors are still important throughout the flowering stage, it is essential they begin and are maintained during the vegetative stage.
- Humidity: A high level of humidity is needed for cannabis plants to produce good growth. A humidity level of up to 75% encourages good development of resin – the sticky, shiny liquid that develops on the buds and leaves.
- Oxygen and Cardon Dioxide: A good balance of carbon dioxide and oxygen is essential to plant health during the vegetative stage. Fans can help circulate air, and move heat generted by the lamps away from the cannabis. Most small grow rooms don’t need excess carbon dioxide contribution, but larger rooms may require a CO2 machine. Remember: the leaves of the cannabis plant breath in CO2, but the roots breath in oxygen, so both is required for good growth.
- Acidity: Whether the grower chooses a hydroponic or soil-based method of growing, a proper pH level should be maintained. A pH of between 5.8 and 6.5 – slightly acidic – is ideal for good growth of cannabis plants.
- Water: Rain water is ideal for growing cannabis, during both the flowering and vegetative stage. Where it is not regularly accessible, tap water that has been left to stand for a few days is a perfectly suitable option.
- Nutrients: If the cannabis plants are grown hydroponically, they are administered a nutrient-rich water at every watering. For soil-grown plants, the soil will carry a certain amount of the necessary nutrients, but eventually these nutrients will run out (often after two or three weeks). A combination of Nitrogen, Potassium and Phosphorous can be added as needed (beware: over-fertilizing can be hugely detrimental).
Marijuana Vegetative Stage Tips
- Choose Your Stage Length. The vegetative stage should continue until the plants are a good size, but it is important to remember they will still grow after the flowering stage commences. It is helpful to know – from personal experience or other growers – how much post-vegetative growth to expect for your specific strain.
- Keep em cozy, but not too cozy. Cannabis plants should be close enough together to make the most of the light source, but if they are packed too tightly, the side branches will not develop properly during the vegetative stage. Weak side branches mean fewer sites that can support the development of buds, and therefore a smaller yield. Overlapping leaves also encourage mold.
- Consider LST methods to get the most out of one light. If the plants get too big and are too close together, however, the light will not reach the lower branches. This also results in fewer bud sites. While it is quite simple to grow a cannabis plant with a large mass of buds at the top, optimizing multiple sites lower down is more complicated.
- Easy on the fertilizer. Watch the leaves when determining how much extra fertilizer to use. If there is still fertilizer remaining in the soil, adding it to the water could over-fertilize the cannabis plants. Nutrients should be increased as the plants grow, and yellowing leaves can indicate that more nutrients are required.