The flowering stage is the moment we all have been waiting for. For you, as a professional grower, this is the most important part of growing marijuana. Let’s discuss how you can take care of your flowering cannabis and grow the best yield ever.
When your plants switch from the vegetation to the flowering stage, the growth will eventually get slower. When the plants start to develop flowers (so called buds), it is time to treat them differently. This means changes in light and different nutrients for the flowering stage.
While plants have been growing and prospering like crazy in the vegging stage, your plants will now be more prone to problems. Everything that happens from here on out will affect your yield – for better or for worse.
The entire flowering stage will be about 8 weeks and consists of the following stages: transition, first buds, growth of buds, buds ripen and harvest.
Different stages of flowering cannabis
Stage 1: Entering The Cannabis Flowering Stage
To introduce your plants to this new stage in their life cycle, make sure you are using the right flowering grow lights. Gradually change the light cycles until you reach a 12/12 hours ratio of light and darkness. Again, growing indoor gives you the perfect opportunity to create an environment that suits your plants best. It's important to take advantage of indoor growing instead of being dependent on the rhythm of the sun. The better your cannabis flowering stages are, the better your yield will be.
The first 1 to 3 weeks of the flowering stage are a transition phase and your plants will still be growing. Your plants could double their height at this point depending on the type of strain you are using.
Stage 2: Spotting Your First Flowers
Before spotting a marijuana flower, you will still want to support your plants in the growth stage as much as possible. Once the flowers are showing, you want to optimize for light and nutrients. Now you can, and should, switch to nutrients for the flowering stage.
Remember: Only female plants will produce buds. You can make sure to have female plants by using feminized seeds.
In week 3 or 4, the first real buds will show instead of only hairy pistils. The growth of the plant will now slow down a lot - it's important to watch out for the health of your plants at this point. A few dead leaves are normal (ex: if they do not get enough light). You do not want a major disease at this point so it's also important to watch your nutrient levels and observe your plants closely to ensure nothing strange is happening.
Stage 3: Glorious, Beautiful Cannabis Bud Pistillation
Finally! Buds with substance. White pistils will be sticking in all directions and the buds themselves will be bigger every day. Congratulations! You have come a long way and your plants are rewarding you. Here's the best tips to follow during the flowering phase to get you here:
Best Flowering Stage Tips for Cannabis
Pro Tip 1: Only cut leaves and branches that are dead
It might be tempting to cut big branches, but your plants need all their power and health they can get right now. Never taste the freshly developed flowers - let them grow in peace. You might bend the plants and tie them down to create a more horizontal table-like shape instead of a Christmas tree shape.
Pro Tip 2: Keep humidity around 45%
When it comes to managing humidity during the flowering stage, keep your grow room between 45% humidity. While cannabis plants do love moisture, especially in the cloning and vegging stages, in the flowering stage you run the risk of powdery mildew on your buds with humidity anywhere about 50%.
Be sure to get a good thermo-hygrometer, measure your grow room daily, and employ the use of a dehumidifier if you see your humidity start to creep up into a dangerous range. A standard 30-pint dehumidifier like this one will work for most setups from small grow tents up to a 500 square foot grow room. For bigger grow rooms (1000 square feet+), consider stepping up to a 70-pint dehumidifier like this one.
Pro Tip 3: Use a carbon-filtered airflow system
If it hasn't happened yet, your plants now might develop the known marijuana smell. Make sure to use a carbon-filtered airflow system. Your airflow system is important at this point and fresh air needs to be constantly flowing into your grow room. In this phase, your plants will need a lot of CO2 (carbon dioxide) for growth and health.
In weeks 4 to 6 of your cannabis flowering, the buds will get bigger and fatter. Once the flowers are showing as small white pistils (white wispy hairs), your plants will need more phosphor and potassium. Both are important for a good bud formation. The nutrients support flowering and fruiting.
Pro Tip 4: Avoid Nutrient Burn
Nutrient burn could be a source of declining health of your plant. Make sure not to over-feed your plant with nutrients. You will notice that the tips of the leaves will seem burned if you over-feed your plants.
Pro Tip 5: Support Heavy Buds to Maintain Light Exposure
You do not have to think about tying your plant down at this point anymore. However, you might consider holding your buds up and close to the light if they are too heavy for your plant.
Pro Tip 6: Trim Excess Foliation
Some pros trim their plant leaves at this point (defoliation) so their plants can focus mainly on bud growth. Make sure to leave enough leaves to support your plant’s health! The leaves are fueling the plant’s system and therefore bud growth.
Around weeks 6 to 8, your plant will have stopped vegetative growth completely and only work on the buds. A few leaves might turn brown at the bottom now and this is perfectly normal. Your plants will be sensitive to a lack of nutrients at this point. Watch your pH levels to make sure your plants get all they need.
Pro Tip 7: Avoid Light Burn
Even though your plants love your powerful grow lights, make sure they do not get burned by high levels of light and heat. If you're using a grow tent, be sure it has enough height for the lights to be at least 12-36 inches above the top of your plants' canopy. If you're using higher wattage lamps (1000W or similar), you should be at the top end of that range, and for lower wattage lamps (250W or similar) you can be at the low end of that range, but make sure you always have at least 12 inches.
A final, supremely important thing to note about lighting during the flowering stage: once you start switching to the flowering light cycles – never go back. Never expose your plants to light in the dark phase of the day. You do not want to confuse your plants or make them switch back to the vegetation phase. This could dramatically impact your yield. It is the un-interrupted darkness that leads your plants to flower. Make sure this darkness is definite - not one minute of light in the night! Use a programmable timer to make sure you don't forget when you need to turn your lights on or off, and be sure to test your settings and confirm they're correct before trusting it on your precious cannabis plants.
Hardly any flowering cannabis will be ready for harvesting before week 8. You will be watching your plants closely at this point, treat them like a lady! Cater to all their needs. It also may be helpful to consider flushing them out using plain water for a few days before harvest. Between week 8 and 10, they should be ready for harvest depending on the strains. The intensity of the marijuana smell could be a good indicator. Your plants might start turning yellow at this point, which is what the plants normally do when they finish up the flowering stage. Do not raise your nutrient levels at this point. Your buds should be big and fat at this point... which means...
You made it! Enjoy your harvest!
Cannabis Flowering Week by Week Pictures
Weeks 6 to 8