What is the Vegetative Stage?

Like any plant, the proper development of cannabis depends on a hospitable environment while the plant grows. In order to achieve a good harvest of numerous, large buds packed with healing properties, your cannabis plants must pass through two phases after you have germinated the seeds: the Vegetative Stage and the Flowering Stage. 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 cultivation—the vegetative stage generally spans four to eight weeks. Following this vital phase, you can induce the flowering stage (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 you planted.  Auto-flowering varieties have a very short vegetative stage, regardless of their environment, because they are all bred 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, so they 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 the stems and branches are 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 healthy vegetative stage will also directly impact the health and quality of the buds you harvest.

Read More: The cannabis types: Indica and Sativa

Maintaining the Marijuana Vegetative Stage

First and foremost: Light

You keep your cannabis plants 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 flowering stage after two or three weeks, regardless of light.

To keep cannabis plants in the vegetative stage, limit the hours during which the plant is in darkness.  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 also 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 or 24 inches 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 and 85 degrees Fahrenheit.  A lower temperature of 60 – 70 degrees Fahrenheit is fine during the night (hours of darkness).

Factors to keep in mind during the vegetative and flowerings stages:

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 Carbon 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 generated 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 breathe in CO₂, but the roots breathe 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: Rainwater is ideal for growing cannabis during both the flowering and vegetative stages.  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 you grow your cannabis plants hydroponically, administer a nutrient-rich solution 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 cause lots of issues).

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 you can expect from 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 bud, 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, 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.