Understanding and controlling flowering phases


It’s obvious why we’re growing plants: we’re looking for the largest, most valuable harvests of the biggest, most potent flowers.
When you understand how to work with the growth tendencies of your plants, you understand how to control your plants so they give you the harvest rewards you deserve.
So enjoy reading this first of a series of articles about flowering phases and increasing the value of your harvests.
flowering phases01Cannabis has two distinct growth phases.
The first phase is from the time a plant is grown from seed or clone until the time the plant begins flowering. This phase is commonly called the “grow phase” or the “vegetative phase.”
During this phase the plant develops roots, puts on height, adds branching, stem and leaf. During this period, no flowers are developing. The plant is developing the infrastructure needed so that flowers can form later.
To get the biggest harvests, you start with the idea that everything you do from the time your plant is first alive until the day of harvest will influence the size and value of your harvest.
Many growers assume that grow/ vegetative phase is just an early phase that has nothing to do with flowering. But you realize that there are many things you can do during grow phase that sets the plant up for large flowers later.
One of the most important of these is to trim the top growth of your plant so that it doubles its leaf sets and becomes a bushier and denser plant that has more room and support for bud growth.
Another is to use hydroponics nutrients designed to create dense, bushy, high-yielding plants.
So while it’s true that bloom phase starts when your plants begin developing flowers, you can consider the entire life cycle to be a bloom phase and always be thinking of ways to maximize productivity, no matter how old your plant is.
In Nature, plants sprout in spring when day length is increasing. They grow taller and denser until the Summer Solstice (which is usually around June 21). After Solstice, day lengths start to decrease. Your plants notice this, and they subtly begin to prepare for flowering.
By the time the daylengths have dropped below 13 hours, most cannabis plants have started flowering.
In indoor gardening, you control the daylength to make the most of crop production.
First of all, you have to figure out how long to let a plant stay in veg phase before you flower it.
Whether growing from clones or from seedlings, the key is to use plant size, appearance and genetic origin as guides for when the plant is mature enough for flowering.
This process is more complex than you might think. For example, if you made clones from a motherplant that was only 4 weeks old, that clone is itself only 4 weeks old and you might need to let it grow Tonger before flowering than if you were working with a clone taken from a 10-week-old motherplant.
If you took a clone from a motherplant that was mature and had just started flowering, you could get away with dropping the clone directly into flowering without giving it time to mature.
If you are growing from seed, however, you need to let the seedling develop in normal, vigorous veg phase growth for at least 5 weeks before you flip it to flowering.
In general, a seed-grown plant is not ready for flowering unless it is at least 77 meters tall. The proper height a plant needs to be before flowering may vary slightly, depending on genetics and on whether you trimmed the plant to make it shorter and denser.
When you flip an immature plant into flowering before it has had a chance to develop adequate roots and other systems, you lose yield because your plant has not had sufficient time to develop roots, stems, stored sugars and metabolic pathways needed for optimal floral production.
In Nature, daylength gradually shortens alter June 21, which in itself triggers plants to prepare for flowering.
Other changes take place as well, most notably the color temperature of the sun spectrum. The glaring whitish blue light of summer gradually transforms to a warmer, more orange light from the late summer and autumn sun. These “color temperature” changes key the plant to produce flowers.
In grow rooms, you use these factors to your advantage. Let’s say you wanted your seed-grown plants to begin flowering when they are six weeks old. Beginning in week four using a light timer you would gradually reduce your lights-on cycle from 18 hour days to a 12 hour day, incrementally decreasing the length by an equal amount every day so that by the start of week six you are at 12 hours light per day.
You could also add an HPS light to your MH in increasing proportion as you get closer to 12-hour daylength. Instead of using a 1000 watt MH for your last week before 12 hour light cycle, you could use a 600 watt MH and a 400 watt HPS.
When you have finally reached the 12 hour light cycle and alter about three weeks into flowering, use only HPS, which duplicates autumn light spectrum and produces lots of flower growth while minimizing stretch and internode distance.
Please note that these instructions are only approximate. Especially if you are growing exotic varieties of cannabis, such as Hawaiian, Thai, Colombian, Jamaican or other equatorial genetics, you might have to experiment with indoor light cycle length and other factors to find out what most quickly induces flowering.
Always remember that cannabis plants are not machines. They have different genetics that influence how they grow, what daylength will make them flower, how long they need to be in flowering, etc. Even if you get ten seeds bred true from a professional seed producer such as Sensi Seeds, you will still see variation within those ten plants.
Also note that some growers believe that white high intensity fluorescent lighting or MH lighting are useful during early flowering or even during the entire bloom phase.
According to these growers, white or blue MH light creates shorter internodes and stronger root growth than HPS, but it also results in lower yields.
You could conduct testing to determine which color temperature of lighting produces the heaviest harvests, most potent harvests, and set the matter to rest in your own mind.
Creating plants that provide huge blooms starts at the start of when the plants are growing.
During veg phase, use base fertilizers specifically designed to create short, dense, bushy growth. Also use trimming techniques that keep your plants Bush and horizontal rather than lanky and vertical.
As you near the 4th or 5th week of grow phase, you will want to blend your fertilizer regimen so that it includes less nitrogen and more potassium and phosphorus. An easy way to do this is to blend a ratio of 75% grow phase base fertilizer with 25% bloom phase base fertilizer.
As with how you incrementally increased your ratio of orange light and decreased your ratio of blue light, along with decreasing your daylength, you can incrementally change your plant’s nutrient mix to reflect the transition to bloom phase.
By the time you reach your 12 hour start date, you will be using a totally bloom phase base nutrient. At the same time, you should also start feeding your plants supplemental formulas that contain hormones, plant growth regulators, and nutrients that create numerous budding sites, early flowering, and unusually rapid floral development.
These formulas often contain extra doses or types of potassium and phosphorus, but that’s not all they should contain. Some of these formulas are comprehensive base nutrients. Others are known as bloom boosters.
At present, the hydroponics nutrients marketplace doesn’t give you a lot of choices when you are trying to find specialty formulas that control flowering. You need to ask grow store stall and nutrients manufacturers to tell you exactly what is in their products, how their products are tested and designed, and what their products are intended for.
It is difficult to find the expert formulas we’re recommending here, but they are made by a couple of manufacturers and a professional grow Shop will stock them. When you have procured them and learned to use them, you will see immediately noticeable increases in harvest size and quality.
After you have switched to 12-hour daylength and as long as your crops are properly triggered, they will begin to change from adding vegetative growth to producing flowers.
There are many ways to use feed regimens that can achieve the following goals:
Increase the number of budding sites Increase the Speed of flower development
Get the flowers to peak bloom faster and hold them in peak bloom plateau longer so they add lots of resin.

Cause flowers to increase in size, density, weight and resin percentages
So you can maximize the use of supplements and base nutrients to increase harvest size and quality, you need to understand that cannabis plants have distinct floral phases:
Transitional Pre-Flowering
Immature Floral Stage
Early Floral Stage
Peak Bloom Late Bloom
Transitional and immature floral stage begin in the week before plants are put into 12 hour bloom phase light cycle, and for up to 21 days alter the 12 hour cycle commences.
Depending on genetics and conditions, plants may even create immature floral clusters as they mature in grow phase. These clusters appear at the tips of leaf stems where they join the main stem. They often display a small number of the white hairs that later occur in abundance during later floral stages.
Here are some tips and data sets that will increase your understanding of transitional and immature floral phases:
Transitional phase may begin up to a week before switching to 12/12 photoperiod to induce the flowering response.
Transitional phase is the period where plants make the physical and chemical change to reproductive growth from the vegetative growth phase. It typically lasts from 8 to 21 days, although some tropical or equatorial varieties may produce transitional growth for months.
Plants often make their biggest gains in stature at this time, and may increase anywhere in size from 25% to 200%.
Keeping your plants “tight” and robust is the objective at this phase.
MH (blue) lighting helps reduce elongation during transitional and immature phases.

Flush excess nutrients, especially nitrogen, out of the growing medium when commencing flowering.
Increase plant available energy by carboloading as plants enter 12-hour light cycle.
Roots are still expanding, so feed beneficial fungi and beneficial bacteria to roots during these phases.
Humic and Fulvic acids will increase nutrient transport demands that are occurring with the accelerated growth rates typically occurring during the transitional phase
“Sucker shoots” and un-wanted growth (typically, bottom 1/3 of plant) should be pruned away, at 7 to 10 day intervals. This helps the plant channel more energy into upper growth that yields better and produces material of higher quality
Bend and tie plants as necessary to optimize growth patterns, maintaining a level crop canopy height to maximize the efficiency of artificial light.
Beware over-fertilization, especially excess nitrogen, which delays onset of flowering and contributes to other cropping problems.
Maintaining similar day/night temperatures will help to keep intermodal distances shorter, creating more flowering sites per meter of growth.
Maintain consistent below 58% humidity levels in the growing area, high humidity will cause plants to stretch more and will produce “soft” growth
Ensure good air circulation through the plant canopy and try to avoid overcrowding.
Some growers opt to introduce beneficial insects such as mite or thrip predators at this point to help eliminate the necessity of spraying the crop with insecticides, even if the release is just a preventative.
Applications of potassium Silicate by foliar or root creates sturdier stems and more disease resistant plants for the later ripening phase.

Discontinue B-Vitamin supplements (these reduce plant stress) during the first one to two weeks of flowering. The plants need stress to help trigger flowering.
Water consumption increases during transitional and immature floral phases so ensure adequate moisture levels are maintained in the growing medium and/or reservoir.
Reduce overall nutrient strength during transitional phase, particularly during the first week.
Plants should never be transplanted during flowering.
Plants should never be “topped” during flowering, unless absolutely necessary. “Top” your plants for Bushier growth habits at least 15 days prior to commencing the flowering phase..
Avoid interrupting the dark cycle by ensuring no ‘light leaks” into the flowering room; light leaks prevent complete flowering and even lead to hermaphroditic plants.
Closely monitor the pH of the growing medium and reservoir, as it may fluctuate with the plants’ increased consumption of water and nutrients during the transitional growth phase.
Keep a cose eye on your plant to light distances to avoid burning plant tops: during the transitional phase plants can easily gain an inch a day in growth.
In the next issue of Soft Secrets, we will explore early flowering, peak flowering and Tate flowering. Just remember that you can use supplements and careful gardening techniques to set yourself up for larger, more valuable harvests.

  • do cannabis plants need more light during flowering


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