The 12/12 method of cultivation does not need any special care except changing the duration of its light cycles. The plants are still to be treated as… Curious to the 12-12 from seed technique (for solo cups) and how to apply this method? Learn more on growing 12-12 from seed and yield potential. 12/12 from seed to harvest is an outdated method of growing weed, but not a bad cycle for bag seeds and perpetual harvest. Learn more!
The 12/12 Method: The New Craze in The Canna-Cultivation World
Cannabis growers all over the world are constantly seeking new methods and ways of cultivation; this is especially true for indoor growers because of space restriction. They believe that having limited space should not hinder their plant growth and yield.
The introduction of a new method known as the 12-12 from seed method has gained wide acceptance among the indoor cannabis growers. The photoperiod cannabis strains usually flower based on their light cycle, this is usually recreated by the indoor cannabis growers to keep them in their vegetative phases and enable them flower. The 12-12 in the name refers to the 12 hours each of light and darkness the plant is exposed to immediately after germination.
The normal method which has been used for a long time is to use an 18/6 cycle in the vegetative phase which takes about 2-4 weeks before switching to a 12/12 light cycle for the flowering phase. However, the 12/12 technique skips the traditional vegetative phase entirely to force them into flowering immediately by making use of the 12/12 light cycle. Rather than the plant focusing on developing its size and leaves, it is tricked into flowering immediately in a bid to reproduce.
It is especially appealing for growers who have serious space problems as the plants grow much smaller and manageable than the regular plant which went through the vegetative phase. They are a lot less bushy and have fewer branches and can produce an average of 5 harvests per year in some cases thus making it more attractive for those growers who don’t have a lot of time. The 12/12 photoperiod growing method is an economical and space-saving way of growing your cannabis plant. It takes an average of only 7-9 weeks straight from seed to harvest which is quite faster when compared to the regular cannabis growth.
The 12/12 method of cultivation does not need any special care except changing the duration of its light cycles. The plants are still to be treated as always, receiving care and love from the grower as always in terms of growing medium conditions, nutrients, pest and disease control among others. This should be monitored most especially while the plants are young just like it would be during a normal bud cycle.
They are easier to maintain as there are far fewer leaves to handle while trimming thus freeing up your valuable time.
It allows for good light penetration to the plants and an easier maintenance routine as the plants are accessible and can be moved around.
They are capable of growing in a tiny area
it is money-saving as there is a reduction in demand for resources like water, nutrients, and electricity across the board and reduces wear and tear on the moving components.
It allows for efficient space-saving as the plants have fewer side branches and do not spread excessively like those grown using the regular method.
The 12/12 cannabis growing method has both its opponents and proponents as some believe that plants that are produced using this method give growers lower yields as a result of being unable to produce budding sites and have lower concentrations of THC. On the other hand, some growers say it is so effective that it produces very good and bountiful cannabis harvests with some of them claiming to get as much as one gram of weed per every watt of light used. Although this might not be the case, the 12/12 cannabis growing method has its merits and will continue to be adopted by many cannabis growers over time.
Resterilizing the grow area after every crop is important to keep it clean and sanitized.
Keep mold and mildew at bay by regularly checking your plants especially those in areas with less light.
The right cannabis plant variety is important for this cultivation method as some varieties like Indica are known to not work well with this method. Hybrids and the Sativa varieties are known to work well as their growth and root development make them ideal candidates for this method.
Powerful lighting and air circulation system ensures that your plants get strong lighting and enough air to develop well.
Your plants will notice any abrupt changes in lighting so use the right one such as the HPS lamps from the beginning and a poor lighting system will result in stunted growth.
It is important to keep in mind that a cannabis plant that has undergone the 12/12 method of cultivation will look different from your regular plants. This is because the photosensitive hormones on your plant make the largest cola its highest point and the plant will likely have a few short branches with only a major bud. However, this is where the difference ends as there is no means of identifying cannabis grown through this method through flavor and effect.
Guide to: 12-12 From Seed Technique
With regular and feminized seeds, you need to determine when to end the vegetative phase and make the plants flower. Usually, it can take several weeks. However, you can force your plants to flower a lot earlier than when they are under regular conditions.
By managing how much light cannabis receives, you can begin harvesting as soon as possible. Some people have time and space constraints. Growing 12-12 from seed is beneficial if you experience both of those challenges.
Continue reading if you want to know more about this process.
What Is Growing 12-12 From Seed?
Growing 12-12 from seed means that you would give your seedling 12 hours of light and 12 hours of darkness soon after germination. Usually, cannabis receives an 18/6 cycle during the early stages of life. Switching to a 12-12 schedule initiates the flowering stage.
With equal amounts of light and dark, your young plants would begin flowering right from the start. Some growers grow 12-12 from seed since it is perfect for solo cup growing. The plant’s roots do not need much room to grow, since the vegetative period will be short.
So, a solo cup or another small container can work well. However, you may need to water cannabis a bit more frequently.
One reason you might want to try using a 12-12 light cycle after germination is the shorter cultivation time. Cannabis typically takes 3-4 months to reach harvest. You can enjoy some nice buds sooner than expected.
Trimming becomes less of a hassle as well. You do not need to manage as many sugar leaves compared to when you grow marijuana normally. You can save money on water, nutrients, and energy as well.
Another advantage of growing weed under 12-12 lighting is the space you can save. The plants can grow in smaller containers, and the branches do not extend too far. Not to mention, cannabis plants are easier to move. You can turn them around for the light to reach all the leaves.
Some growers do not grow 12-12 from seed due to a few of the disadvantages. One of the main drawbacks is the reduced size of the plants. The shorter vegetative phase means the plant has less time to mature to its full mass. Still, you can get desirable yields.
You would not be able to do a lot of the training techniques as well. Most of them occur during the vegetative stage, so you would not have enough time to do something like monster cropping. One of your options would be low-stress training.
Expected Yield When Growing 12-12 From Seed
If you are intrigued by growing marijuana with 12-12 lighting, you might wonder how much you can harvest. The yield weight is usually not that hefty, but the lights, strain, and pot size can make a difference.
If you grow a seed in something like a solo cup, the average amount is 3.5 grams. You can get around 14 grams from a plant with a slightly larger pot. Some cannabis growers prefer to use containers of up to a gallon. They can get up to 28 grams for each plant.
However, you can get much more from your crops if you grow them with the SoG method.
How to Grow Cannabis 12-12 From Seed
Growing a cannabis seed with a 12-12 light cycle only has a few steps. They are simple to do, and you do not need much when it comes to equipment. If you decide to use this method to grow weed, what you need to do is:
1. Germinate Seeds
For germination, the seeds need some dampness and a warm environment. There are multiple ways you can go about germinating cannabis seeds. Some growers buy starter cubes since they are convenient.
They contain some micronutrients to encourage the roots to grow. Add some water and wait a few days for the germination process to complete. Instead of a starter cube, you could use a non-porous paper towel instead.
Take a paper towel and make it damp. Then, you would fold it over the seeds and wait around 1-4 days. It is helpful to have a spray bottle around since the paper towel can dry out. You can check periodically to see if the taproot emerged.
Once you see roots, carefully remove the seeds and move on to the next step. For tougher seeds, some growers leave them in a glass of water overnight. You could soak your seeds in water and place any stubborn ones in a paper towel afterward to get them to sprout as well.
2. Plant Seeds
Now, you need to plant your germinated weed seeds. You will need to gather tweezers, growing medium, and a pencil. You should also have a small container or lightproof pot. Once you have everything you need, fill the container with soil or another type of growing medium.
The soil should reach just below the top of the container. Many growers fill it up to about 1 centimeter from the top. Then, you would make a small dimple in the dirt with a pencil. The hole should be a couple of centimeters deep.
Use the tweezers to pick up the seed and carefully place it in the dimple. When it is in the hole, you can cover it with a layer of soil. It is necessary to avoid pressing down firmly on the growing medium. The sprouting seedling could have a harder time emerging from the topsoil.
Spray some water to dampen the soil, but you should not add any nutrients at this time.
3. Switch Lights to 12-12
After a couple of weeks, you will see the seedling get bigger. You then can switch the lighting schedule to be 12-12 around the 3-week mark. The plant should start flowering as early as possible. Once it does, you can expect most strains to take roughly 12 weeks to be ready to harvest.
Many seedlings do not begin to flower immediately under a 12-12 light cycle. They usually do not start producing buds until they are 3-4 weeks old. It will not be long until you see some desirable results.
Tips for the Best Results on Growing 12-12 From Seed
Stay On Top of Your Plant’s Need
Even though the life cycle is shorter than usual, you should still pay attention to the plant’s needs. You have to monitor airflow, soil pH levels, and water quality like you would during regular marijuana growing.
Pests and mold can still be a problem. The plants can experience stress, which may mean stunted growth. Not to mention, the number of nutrients a plant receives can change as it gets bigger. You do not want the young seedling to suffer from any deficiencies or burns.
Some growers are concerned that growing 12-12 from seeds reduces yield sizes, but all these factors can ensure a maximized harvest.
Use the SoG Method
If you want to boost your yield size, you can use something called Sea of Green (SoG). The SoG method involves growing many small plants together instead of larger ones. You would place one or two plants down for every square foot.
The SoG setup does not require much effort, and you can grow various strains. However, you would need at least four plants for this method.
The technique works well with growing 12-12 from seed. You would change the light cycle around the third or fourth week, which increases how much you harvest in the end.
Do Not Use Autoflowers
Growing seeds under a 12-12 schedule would not be effective for autoflower plants. You would not be able to get the results you want. The reason is that autoflowers do not need a light cycle to transition to the flowering phase.
As a result, it would not matter if you use a 12-12 or 18-6 schedule. The autoflower plants have their own timeline, and you have less control of their flowering pace. A few autoflower strains might reach harvest sooner than other seeds.
You can buy one that reaches its harvest time quickly if you need to finish growing cannabis sooner.
Final Thoughts on Growing 12-12 From Seed
Many growers like to grow 12-12 from seed, and others do not. You can try it out to see if the method is something you will enjoy. A part of marijuana cultivation is figuring out what works best for you.
Before you get started, you should buy some suitable strains for growing 12-12 from seed. The ones that react the best have a fair share of Indica genetics. The light change is not as effective for Sativa-dominant seeds.
One strain you can try is the Big Bud. The plant naturally has the potential for a large harvest, so you could get more when growing 12-12 from seed. The strain also is great for SoG if you choose to apply the method.
Grape Ape seeds can grow under almost any condition. They can have significant yield sizes and have high THC content. Alternatively, Pinkman Goo is a mixture of other great strains. While sticky, you can get some tasty buds.
12/12 From Seed to Harvest: When to Choose This Method
Doing 12/12 from seed is mostly a relic of a bygone era, but it’s not a bad way of growing weed and can even offer optimal results in some situations.
The 12/12 from seed to harvest method is a bit outdated, but still has its uses. In this article you can learn everything about yields, pot size and plant size, flowering time — in short, all that you can expect when running 12/12 from seed in your grow.
If you have grown weed before, you probably understand what ‘12/12 cycle from seed’ means. And for the novice growers, the following short paragraph explains all the science.
Cannabis is a short-day plant, meaning that it only starts to flower when days become short enough at the end of summer or the beginning of fall. Indoors, we mimic this by shortening the lighting cycle to 12 hours of light and 12 hours of darkness (12/12) and thus inducing the flowering. Usually, we do this after several weeks of the vegetative growth under 18/6, but sometimes you can reprogram your timer to 12-12 from the day your sprouts emerge. And this is exactly what we mean by 12/12 flowering from seed.
These Black Widows clones were put under 12 and 12 as soon as they rooted. Not exactly a 12-12 from seed scenario, but the idea is the same. Wonderful results btw.
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Growing Weed on 12/12 From Seed: Right Reasons and Wrong Ones
Frankly, this is a notoriously low-yielding method, so there must be other reasons to still choose it, right? Of course, there are.
1. Bagseed Growing
Okay, you’ve bought some buds with seeds in them, liked the smoke, and decided to give those bag seeds a try. Not the most brilliant idea ever, but okay. You don’t know how these seeds will turn out until they’re well into flowering, and this can be in like 1.5-2 months from sprouts (if grown in a regular way). Probably, too much time to spend on a dark horse, right? And here the 12/12-from-seed-no-veg method can easily save you 2-4 weeks or more.
2. Using Regular Seeds
It’s the same as with bagseeds. A certain percentage of regular seeds (probably around 50%) will grow into males, and you want to spot them and discard them as soon as possible. Again, 12/12 lighting from seed saves you several weeks of precious time.
3. Perpetual Harvest with no Extra Veg Room
Some people have just one grow space, but prefer to run a perpetual harvest operation. Obviously, your only grow room will be the flowering room, with lights running at 12/12 continuously. So the only way to add new plants after you’ve harvested some of their predecessors is to give the newcomers 12/12 from seed to harvest.
4. You Don’t Care About Yield, But Value Variety
At one time, I was crazy about mix packs that some breeders sell because they gave me the opportunity to grow (and later enjoy) several different genetics in one go. So I used to put 9 different strains in my 2’x2’ grow tent and run them in a 12/12 cycle from seed. The yield per plant was underwhelming, but more than enough for me. The main thing was that every smoke came out different in terms of effect and flavor.
So, these were the good reasons to choose the 12/12 from seed to harvest method, and here are the bad ones:
- Microgrow/Limited Height. In small grow spaces with a short distance to lights, you’ll probably be better off raising autoflowers in small containers. The alternative is having fewer plants, but training them in veg (topping, LST, ScrOG) to have a flat canopy. Both of these options will guarantee you better yields.
- Weak lights. Some people who use tubular fluorescent lamps (like T5) or something similar (CFLs, LED bulbs) think that lighting systems of this kind call for a SOG grow with many budstick plants in solo cups. It’s probably true, but again autoflowering seeds will give you better results than photoperiod strains grown on 12/12 from seed to harvest. And yet again, simply training those during normal veg would be more effective, too.
- Expectation of a faster turnover. Questions like “How long does 12/12 from seed take?” (which people ask all the time) prove that many of them regard this method as the fastest way to harvest. In fact, it doesn’t really make your plants finish much faster, if at all. More of it below.
There is one more aspect of growing weed 12 12 from seed that we have briefly touched upon when talking about bag seeds and regular seeds. Here it goes.
Some growers try out every bean they lay their hands on in search for a hidden gem. Well, it’s a noble quest, and the 12/12 from seed method allows you to quickly assess the genetics. But suppose you’ve found a phenotype you like. Now what?
You have two options: one is cloning a plant that is already flowering, the other is reverting it back to veg (a procedure known as ‘reveg’).
Taking a cutting from a flowering plant and then rooting it is a fairly difficult procedure compared to cloning in a regular way (when the plant is still in veg). It takes longer and the success rate is lower. (There is an upside, though: the resulting clone turns out into an insanely branchy little monster; hence the name of this procedure – monster cropping.) Another difficulty is that plants grown 12/12-style are basically a ‘bud on a stick’ and often have no side branches to use as cuttings.
What’s the Alternative to Reveg Then?
If you’re searching for a keeper, try vegging every plant for a few weeks, then take a back-up clone from each, and then flower all donor plants to see if there’s a champion among them. It’s easier this way.
The same goes for reveg. Reverting flowering plants back to veg is hardly a beginner-friendly procedure, and can take months (with no guarantee of success). Do you know that some growers in colder climates use this feature to have the harvest in the middle of summer? They make their plants flower indoors for 4 weeks, and then put them outside. And no reveg happens, even though summer days are much longer than nights. Why? Because reveg is a difficult process and requires so much more than simply reverting to 18/6 or even 24/0.
Revegging a plant after harvest is a painfully slow procedure with uncertain prospects.
12/12 From Seed vs Autoflower Growing
In many ways, the 12/12 from seed method is similar to the cultivation of autos, but autos have a much better potential because they can flower on 18, 20 or even 24 hours of light a day. All this extra energy will be transformed into extra bud weight and raised amounts of THC and terpenes. There was a time when autoflowers weren’t high-yielding or potent enough to compete with their photoperiod counterparts, but it’s long gone now. Today, the 12/12 from seed vs auto choice is a no brainer.
And by the same logic, the worst thing you can do is to grow an autoflower on 12/12 from seed. Sometimes people are forced to do this: for example, when there is some free space in the flowering room, but no extra seeds, except autoflowering ones, to fill it. But autos raised in this manner usually stay small and yield little.
12/12 From Seed Instructions and Tips
So, you have a grow room dedicated to the 12/12 from seed to harvest grow. Start by programming your timer so that the lights turn on for 12 hours of light every 24 hours, and then germinate some seeds using your favourite germination method.
This is what you may expect when growing weed in a 12/12 cycle from seed.
What Size Pot for 12/12 from Seed Works Best?
You don’t need a lot of space for your plants’ roots because the vegetative stage will be very short and then the root system basically stops growing. So use solo cups (party cups) or small plastic containers. The pot size can be anywhere from 16 oz (0.5 L) to a gallon (3.78 L). Keep in mind that the smaller the containers, the more frequently you’ll have to water them. More medium also means better buffering for nutrients and less risk of a nutrient burn.
Also different strains react differently to 12 and 12 from seed. Some will take many weeks before they even start flowering, and they will require bigger containers. Growing in 1 litre pots will do fine for most varieties that are worth growing this way.
When Does Flowering Start?
Even on 12/12 from day one, weed plants don’t start flowering right away. Vegetative growth is an important process and will run its natural course. Expect at least 3-4 weeks before the plants are mature enough to show their sex. Of course, when it happens, they will start to flower immediately. As you can see, this is basically the same timeline as for autoflowers.
How Long till Harvest?
Most 12/12 enthusiasts report that their plants finish in 70+ days from sprouts, although some phenos can take up to 3-4 months. Again, autos can do much better than that, and they’ll yield more, too. The reason is that the yields are proportionate to the hours of light a plant receives, and you can give autos from 18 to 24 hours a day.
The Final Size and Yield
It all depends on a lot of factors — strain, pot size, lights etc. It can be as little as an eighth (3.5g) or less from a sickly runt in a solo cup, or up to a half ounce (14g) in a 16oz (0.5L) cup. In the latter case, the skinny one-cola plants will be upwards of 2 feet (60+cm).
This is how a harvested plant can look like if grown 12/12 from seed. Hardly inspiring. I’d even say vaguely humiliating.
Some 12/12 growers prefer even bigger plants in containers of up to a gallon (3.78L): their height can be 3-4 feet (90-120cm) and more, and the yield per plant of 0.5-1oz (14-28g) is considered very good. And it really is, if you grow many such plants SOG-style. There are even reports of plants yielding as much as 3 ounces (85g) each.
SOG (Sea of Green) is the Only Viable Option
Given that the size of the containers is quite small and the plants are lanky, with almost no side branches, we recommend cramming as many of them as possible into your grow space. This way your yield per square meter can prove to be not so bad after all: let’s say 30 half-ounce plants under a 1000W HPS. Hardly record-breaking for a SOG grow, but still.
Would-be 12/12 growers often wonder whether they can train their plants or not. I think the logic here is the same as with autos: any HST technique, like topping, would just lower the yields and (possibly) delay the harvest time. Besides, any training method, including LST, raises the question of spacing: if the plants stand next to each other in tight rows, you shouldn’t try to make them wider and bushier. The single-cola pattern is probably the best.
The Best Strains For 12/12 From Seed To Harvest… and the Worst
As we have said earlier, this method is best reserved for seeds of unknown origin and potential. But if you insist on growing store-bought seeds this way, choose an indica. Indica strains tend to react quite early to the change in light cycle, and if you give them 12/12 from sprouts, the veg will be very short and the plants will remain nice and compact.
As for sativas (like Haze) and sativa-dominant genetics, they have evolved in regions near the equator where days and nights are close to an equal length the whole year. So, they can remain in veg for many weeks and even months before they even show their sex. It kind of defeats the purpose of 12/12. The plants will be neither fast, nor small, and the yields will be disappointing because of too little light hours received in veg.
12/12 From Seed Feeding Schedule
The first thing you should take care of is the development of roots. We recommend using some rooting stimulator when watering your plants in the first two weeks or so.
As for nitrogen-rich fertilizers, it all depends on the pot size. In bigger containers, the soil will probably have enough nutrients to last for the whole of veg. In smaller pots or cups, the plants will need a nitro boost early on. Continue to feed them with veg nutrients till they reach the final height and stop stretching further. This usually means a couple of weeks into flowering.
Starting in the third week from seeds, introduce the bloom fertilizers (with raised P-K levels). First use them along the veg ferts and then without them. 2 weeks before the harvest is time to start the final flush.
The Bottom Line
There are a few special situations where the 12/12 from seed to harvest method can lead to results that are by no means spectacular, but optimal under given conditions. In most other cases, using it would be a mistake. Always check whether you can achieve the same goal with autoflowers, or other growing methods. And if you don’t agree, please share your opinions in the comments.