The final stage of a cannabis plants, which is also the most exciting time during your growing journey, is the flowering stage. Because during this time, the plant will begin to develop its highly sought after buds.
Choosing the right time to transition cannabis plants from the vegetative stage to the flowering stage can significantly impact the health of your plant and in turn affect the quality of the final yield.
Other than timing, there are numerous critical factors to consider such as the ideal number of weeks for the vegetative stage, the necessary node development, as well as what nutrients to feed it at this time to produce the most fragrant and flavorful buds.
Below, we will explain what happens during this period of time and how to maximize your yield and the potency of your buds.
How the Flowering Stage Starts
Cannabis plants naturally switch from the vegetative stage to the flowering stage when it detects changes in daylight hours, which usually happens at the end of summer going into autumn. It acts as a signal to prompt the plant the end of summer and the oncoming winter. Out in the wild, cannabis plants will flower to receive pollination so it can produce seeds to renew its growth cycle next year. But as cultivators who want to harvest the flowers for use, we can control when to trigger this flowering stage by controlling light exposure.
Photoperiod cultivars can detect changes in lighting and begin the flowering stage, whereas autoflower cultivars which contain ruderalis genetics, can ignore changes in lighting, allowing you to maximize photosynthesis, and it will automatically flower once it reaches maturity.
Reducing the lighting of photoperiod cultivars from 18-24 hours to just 12 hours of light and dark will initiate this important stage in the plant’s life.
In controlled environments like indoor grows, 8-11 weeks of flowering is a good amount of time, but ultimately, this timeframe will vary depending on the strain you’re cultivating.
Lighting Changes
The vegetative stage ends when the light cycle shortens, which usually happens when the season changes from summer to autumn. If you grow indoors and have your own grow lights, you will have full control over the lighting conditions. And you will be able to induce the flowering stage artificially anytime of the year.
You can do this by adjusting the lighting schedule of 12 hours of light and 12 hours of darkness. This will force photoperiod plants to flower on command. Transitioning from the vegetative stage into the flowering stage.
Autoflowering cultivars will initiate the flowering stage automatically based on their age as opposed to changes in lighting conditions.
Below are some factors to take into consideration when deciding whether your plant is ready to switch to a 12 hour light cycle:
It is vital to be fully aware of growth patterns your strain genetics are prone to exhibit.
Certain strains are known to grow vertically very rapidly once it experiences a reduction in lighting hours. In fact, many indica strains are known to exhibit this type of growth pattern.
In other cases, certain strains have sudden growth bursts laterally as it transitions in to the flowering stage and can develop additional nodes at a rapid rate. Which can pose as a problem if you have limited space for growing.
To help manage these types of situations, it is imperative for growers to first fully understand your strain’s potential growth pattern prior to initating the flowering stage. In either of the above cases, we recommend practicing training techniques during the vegetative stage to help control the size of your plants and to strengthen their structure. It will also help you gauge and maintain the size of your plants.
We highly recommend using various training techniques to help manage plant size, but also optimize light exposure and growth potential.
Techniques such as low-stress training (LST) or screen of green (ScrOG) encourages earlier flowering. Whereas Topping and Super Cropping methods require a longer vegetative stage to allow the plant to fully recover before flowering. Most strains will need at least 2 weeks of vegetative stage for it to properly recover.
For this reason, we do not recommend using high-stress training techniques on autoflower plants. Because their growth cycle are harder to manage and does not allow growers the ability to control the length of the vegetative stage. As a result, high-stress training methods can result in doing serious harm to the plant and negatively impacting your yields.
If you are cultivating fast-growing indicas, you can transition them quite early on in the vegetative stage to keep them short.
Or you can choose fast-flowering autoflower cultivars that will speed through the entire process in just 7-8 weeks. They rarely develop much height during this time and will be ready for harvest sooner than others.
The longer the plant’s vegetative stage is, the larger they become. And the more bud sites are exposed to light, the larger the potential yield is. So for the most yield, we recommend growing monstrous plants that are tall and bushy, so they can be capable of producing and supporting numerous colas that can eventually yield an incredible amount of usable bud.
Lighting Configuration
Most LED grow lights have a vegetative stage and bloom setting. The vegetative setting will emit more blue light to mimic spring and summer. Whereas the bloom setting emits more red light to mimic late sumemr and autumn.
Other lighting systems have dedicated bulbs or lamps with similar settings. For example, HID lights have metal halide lamps for vegetation, and high pressure sodium lamps for flowering.
Nutrients for Flowering
Once your marijuana plants are in their flowering phase, they require different nutritients. They will need a lower percentage of Nitrogen but much higher percentages of Potassium and and Phosphorus.
The NPK ratios for different stages are as follows:
| Vegatative Stage | Early Flowering Stage | Late Flowering Stage |
|---|---|---|
| Nitrogen: 3 | Phosphorus: 1 | Potassium: 1 |
| Nitrogen: 1 | Phosphorus: 3 | Potassium: 2 |
| Nitrogen: 0 | Phosphorus: 3 | Potassium: 3 |
Airflow, Humidity, and Temperature Adjustments
During the flowering period, marijuana plants require lower humidity levels of about 40-50% and slightly cooler temperatures of around 65-80°F.
Reducing the temperature and humidity will prevent mold and promote optimal transpiration. Most importantly, it reduces the likelihood of fostering pests and pathogens that can harm your plants during this crucial developmental stage.
Maximizing Bud Production
If you’re a first-time grower, maximizing bud production is probably not high on your list of priorities, but once you’ve achieved your first successful harvest there are some basic techniques like topping that you can employ to potentially increase yield sizes.
Topping
Topping a marijuana plant is different from trimming (removing buds) and pruning (removing unhealthy leaves or branches). Topping involves cutting off the top of the main stalk during the vegetative growth stage to increase the number of colas—or main branches—leading to more bud sites and potentially higher yields.
Before topping, ensure your cannabis plant has at least five nodes on its main stalk, although six or seven is ideal. However, don’t wait too long, as topping too late can reduce bud production. When ready, use sharp, disinfected pruning scissors to cut just above the fifth node in one clean snip. Proper topping promotes vigorous growth and stronger branches for healthier plants.
Other Techniques
Once you have gained the confidence that comes with experience, we would encourage you to learn more advanced cultivation practices like fimming, the Screen of Green (ScrOG) method, and other low-stress training (LST) methods, as all of these can aid in maximizing bud production.
Feeding and Flushing
In the final weeks of flowering, stop feeding your cannabis plants and only water them. Doing so will flush out any remaining nutrients, which serves to improve the taste of your buds.
Knowing When to Harvest
There are two key visual signs that indicate your marijuana plants are at the end of the flowering stage and are ready to harvest. First, the white pistils (hairs) on the buds will darken, deteriorate, and begin to curl. Second, with the aid of a magnifying glass, you’ll see that the trichomes have turned white, and the resin has taken on an amber hue. When approximately 70% of the pistils have darkened, it’s time to harvest and start the drying and curing process.
From the germination stage to the vegetative period to the final flowering phase, each cannabis growth stage requires careful attention to lighting, nutrients, temperature and humidity levels, and training techniques to ensure a successful harvest. By mastering these basics, you’ll be on your way to reaping a healthy yield of luscious buds. Feeling confident in your new skills? Take it up a notch! Explore our website for more tips and tricks to elevate your cannabis cultivation game. Let’s grow something amazing together!