Marijuana plants spend less time in grow phase than in bloom phase, and marijuana bloom phase often reminds us of the Tom Petty song that says “the waiting is the hardest part.”
Can you speed up bloom phase while still having your marijuana plants produce their heaviest, most potent harvest faster than it normally would?
Let’s take a look at the common bloom phase acceleration strategies and see if any really work…
Marijuana Genetics & Bloom Phase Duration
The obvious, easiest way to have a fast bloom phase is to grow marijuana strains that have a fast bloom phase. These strains often but not always have heavy Indica influences and can finish bloom within 45-50 days.
Photoperiod marijuana strains with significant Sativa influence rarely have bloom phase lasting less than nine weeks.
Autoflowering cannabis is advertised as finishing faster than photoperiod strains because autoflower plants start flowering without light cycle manipulation within 2-4 weeks of germination.
Seed companies often claim total autoflowering crop time from germination to harvest is usually 7-10 weeks.
However, we’ve grown dozens of autoflowering strains and only a tiny percentage have finished that fast, and they didn’t produce heavy harvests or potent buds.
Fortunately, a few autoflowering seed sellers are being more honest about crop cycle duration.
In our experience, autoflowering strains producing harvest weight and potency almost as good as photoperiod strains of the same type (autoflower Haze versus photoperiod Haze, for example), aren’t ready much earlier than photoperiod strains when you compare overall crop cycle duration.
The generic expectation for photoperiod strains grown from seed is 3-5 weeks in grow phase, 8-12 weeks in bloom phase.
Autoflowering strains spend 2-4 weeks in grow phase and about two months in bloom phase.
You may save a few days using autoflowering strains, but they often have lower yields and potency than photoperiod marjuana, and you can’t easily (or at all) clone or breed autoflowering strains.
You trigger photoperiod cannabis to begin and stay in bloom phase by giving it 12 hours of total, uninterrupted darkness and 12 hours of light during every 24 hour period.
In some photoperiod strains heavy with Sativa genetics, we’ve had to give 12.5-13.5 hours of darkness per day initially, to push the plants out of grow phase and into bloom phase. In rare cases, we’ve had to continue that regimen to keep plants blooming properly.
In the vast majority of cases, however, giving less than 12 hours of light every 24 hours doesn’t accelerate the onset or rate of bloom phase floral maturation. It also deprives plants of light energy they need for maximal bud formation.
Please look at this article on the concept of “daily light integral,” to get more information about total light delivered to your plants per 24 hour period.
Some growers experiment with interrupting the dark cycle, making plants endure 1-2 days of total darkness, far infrared light, dialing in different light wavelength recipes and other tricks they believe are clever bloom phase hacks that accelerate bloom phase finishing.
We’ve tried these tricks, and looked at cannabis/light research data, and find no evidence these methods make bloom phase shorter or more productive.
Instead, these methods often cause needless stress for marijuana plants, leading to hermaphroditism, a longer bloom phase, and other problems.
Torturing Marijuana Plants
Some growers torture their marijuana plants, believing plants react to stress by hurrying up and finishing bloom phase. Torture tactics include creating drought conditions, light deprivation, starving plants of nutrients, and other cruelties.
The cannabis torture program has the same mistaken ideology as marijuana flushing.
The idea that you get your heaviest, most potent harvest by tormenting your marijuana plants makes about as much sense as the idea that starving your marijuana plants during their last days of life (flushing) produces the heaviest, most potent harvests.
What really happens when a grower does deliberate harm to their marijuana plants by underwatering or underfeeding is the cannabis plants respond by fading faster than they normally would.
Flowers and resin glands shrink, the leaves show nutrients deficiencies, etc.
If bloom phase is shorter under these conditions, it’s often because plants are giving up. They’re being treated badly at the end of their lives, similar to how elderly people are often treated in nursing homes.
Ironically, many tactics growers use to shorten bloom phase decrease plant metabolism and floral maturation rate, leading to longer bloom phase, lower harvest weight, and less cannabinoid percentages.
So we’ve seen that common tactics for shortening bloom phase don’t work and are often detrimental. Is there anything you can do to make bloom phase as short as possible?
Try giving your plants optimum environment, lighting, reverse osmosis water, fertigation cycles, root zone size and feed program for their entire life cycle.
Adopt a calmer attitude towards bloom phase. Like fine wine, your marijuana buds need time to ripen and mature so they’re as heavy, tasty, aromatic, and potent as possible.
Bud Hardeners, Bulking Formulas, Bloom Phase Accelerators
General Hydroponics makes a product called “Bush Load” that they claim accelerates bud formation and makes “harder” buds.
Bush Load contains Paclobutrazol, a controversial plant growth regulator banned in most legalized marijuana state’s regulations because scientists suspect it’s a carcinogen and damages the liver when its ingested during gardening or by consuming Paclo buds.
Other companies also make products that allegedly accelerate bud production and increase bud density. These products include B-Nine WSG, Ethephon 2 SL, Rock Resinator, Bushmaster, Hulk PGR, Phosphoload, Gravity, and G-10.
Some but not all these products contain Paclobutrazol and/or daminozide (Alar). Too bad these substances are not safe for use on marijuana plants.
Advanced Nutrients makes Bud Ignitor, claiming the product creates more and earlier budding sites and faster bud formation.
But according to the label, all this product contains is phosphorus, potassium, and kelp, and we’ve never seen any objective proof it actually accelerates or improves marijuana bloom phase.
Some of these products are advertised as being “vertical growth limiters,” which means they inhibit upward growth, making plants shorter than they’d normally be.
Problem is, when we tested those products, we noticed that they reduced harvest weight and resin gland formation!
We’ve used all these expensive products in side-by-side testing and seen no worthwhile effects.
In fact, some of these expensive products severely damaged our plants and buds and/or they contain plant growth regulators and other chemicals said to harm human health.
The California Department of Food and Agriculture, along with other regulatory agencies, have banned many of these products and ordered grow shops to stop selling them.
That’s why products sold to marijuana growers as bud hardeners, bud bulkers, resin boosters, height limiters, and bloom phase accelerants are sometimes sold clandestinely, black label, from under the counter.
I’ve shopped at hydro stores where they keep these banned products hidden away and only sell them to “trusted” customers.
One Reliable Bloom Phase Accelerator and Bud Builder, Yay!
Many bloom acclerator products only contain potassium and phosphorus.
Some contain covert chemical or naturally-derived plant growth regulators (PGRs) or precursors for PGRs.
In extensive testing using clones, professional growers report that a bloom phase accelerator product made by TPS Nutrients called Bloom Flower Builder actually does work.
We’ve written about other TPS products because they work well. The company is owned and operated by real growers and plant scientists based in Seattle.
When you talk to their grower support people, it’s like chatting to your most successful grow buddy who also happens to be a cannabis science expert.
Not only that, TPS website prices are lower than the same product’s price on Amazon, and shipping is ridiculously fast.
Professional growers use TPS Bloom as a root feed and a foliar spray.
They use it as a foliar only during the last week of grow until the second or third week of bloom, because spraying powerful plant boosters on peak bloom resin glands damages glands, and spraying anything on formed buds promotes bud rot (gray mold aka Botryrtis).
TPS products are proprietary in that they rely heavily on organic and naturally-created components.
Their Bloom Flower Builder of course contains phosphorus and potassium, but those elements are formatted in a way that facilitates rapid intake.
Naturally-produced precursors that form bloom accelerating, bud bulking plant growth regulators are also on-board.
So you get all the benefits of manipulating plant growth regulation, without the cancer, liver damage, and plant harm caused by General Hydroponics and other chemical bloom booster products.
We recommend talking to TPS about using a suite of their products--Silica Gold, Signal (a terpenoid/cananbinoid booster), Canopy Growth (magnesium supplement), and Bloom–to increase harvest weight, rate of maturation, quality, value, and potency of your buds.
One final note—there may be times when you desperately need bloom phase to hurry up and finish.
In that case, you could let your buds and resin glands mature as long as you can afford to, then harvest some or all of the buds “early.”
Some marijuana growers do this anyway by engaging in incremental harvesting.
This happens when you start harvesting a few buds off each plant beginning 10-14 days before culmination of the strain breeder’s predicted bloom phase duration.
In some situations, you find out that the buds harvested “early” give you a better high than buds harvested at peak ripeness. In other situations, the early-harvested buds produce a high that’s too light and edgy.
But because the buds and resins haven’t had time to fully ripen, you tend to get a thinner, shallower, less-impactful high, and your harvest weighs less.
So now you know how to accelerate marijuana bloom phase while boosting the value of your harvest. Here’s some relevant entertainment while you’re waiting for that next crop to be ready for cutting…