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flowering weed straight from seed

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The 12/12 from seed to harvest method is a bit outdated, but still has its uses.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.

Cloning/Reveg

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.

Topping/Pinching

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.

How to grow weed outdoors: an intro to outdoor cannabis cultivation

Outdoor cultivators take what Mother Nature gives them and turn it into the best possible harvest. Many cannabis consumers prefer marijuana grown outdoors under the full spectrum of natural sunlight. That unique spectrum creates a greater variance of cannabinoids and terpenes than artificial lighting.

Cannabis has been cultivated outdoors for thousands of years, but before you go putting a seedling in the ground, it’s best to know how the process works and how to make the most of Mother Nature’s gifts. You should also have some idea of how to handle those unwanted gifts you’d rather return — pests and weeds.

How to grow marijuana outdoors

To grow cannabis outdoors, the bare minimum required is basic gardening tools, soil, water, and a spot in your backyard that receives ample sunlight.

Using Mother Nature to cultivate cannabis

Cannabis is a hardy plant that has adapted to climates all over the world. From the cool and arid mountains of Afghanistan to the humid regions of Colombia, over time the plant has been forced to adapt its defenses against a host of problems. But cannabis is still susceptible to extreme weather conditions. Whether it is heavy winds breaking branches or excessive rain causing mold, the great outdoors presents challenges to growers that can be mitigated with sufficient planning.

Becoming intimately familiar with your local climate and seasons is one of the most important steps in producing high-quality outdoor marijuana. Before you grow, you’ll need to know the ideal temperature your plants require in order to thrive, the best site, optimal timing of planting and harvesting, and the season’s photoperiod — the amount and intensity of light available through the duration of the growing season.

Some cannabis genetics have adapted to specific climates and are capable of growing more easily in certain conditions than others, so pay very close attention to the cultivars, or strains, that you choose. A little research will go a long way in ensuring you have a successful harvest.

While cultivars may vary, here are some general rules that will be useful no matter which one you choose.

Temperature

Daytime temperatures between 75 and 85 degrees Fahrenheit (23.9 to 25.4 degrees Celsius) are ideal for cannabis, while temperatures above 88 degrees Fahrenheit (31.1 degrees Celsius) or below 60 degrees Fahrenheit (15.6 degrees Celsius) can delay growth. Cannabis is considered heat-tolerant, but sustained highs and extreme lows will usually lead to complications that could eventually kill your plants.

Season

In the Northern Hemisphere, cannabis can be planted in early to mid-spring and harvested in mid-fall, depending on the cultivar. In the Southern Hemisphere, the growing season will be reversed with planting in early to mid-fall and harvesting in the middle of spring.

Light

During the first half of the season, the daytime period increases until the summer solstice, which occurs in the Northern Hemisphere on or around June 21 and in the Southern Hemisphere on or around December 21. While the daylight hours increase, the plant’s vegetative stage takes place. During vegetation, the plant will develop the roots and stems that will serve as the foundation for growth until flowering.

After the solstice, the available daylight hours decrease, allowing the plant to naturally transition into the flowering period. Cannabis is a short-day plant, meaning it will begin to flower as the nights get longer and the hours of sunlight decrease.

Most cultivars will begin to flower once they receive fewer than 15 hours of sunlight per day. The latitude of your garden has a direct impact on how many hours a day your plants receive light.

Plan to put plants in the ground based on the temperature, season, and light where you live so your cannabis plants have time to finish flowering before cold, rainy weather sets in.

Choosing the best site for outdoor cannabis

Determining the optimum location is another important factor that can affect the yield and quality of your plants. Cultivators in the Northern Hemisphere should attempt to place their plants in an area with southern exposure to ensure their plants are getting the most available sunlight. The opposite is true for the Southern Hemisphere.

When possible, use natural structures and formations in your garden as windbreaks to prevent excessive stress on your plants that could lead to branches breaking.

If you live in a climate with exceptionally hot and sunny days, use shade cloth to prevent your plants from overheating. In cold areas, natural enclosures and cement or brick walls can be used to help retain any available heat and keep your plants warm.

Depending on your location, you may need to plan for rain. In most regions, the rainy season is typically aligned with the end of the flowering stage and the start of the harvesting period, but this may not always be the case. Rain can be detrimental to an outdoor flowering crop so being prepared to cover or move plants can help ensure a successful harvest. If it does rain on your plants, make sure to immediately shake off any excess water, as lingering moisture can lead to the formation of mold and nobody likes moldy weed.

Planning your garden

Seeds vs. clones

Deciding whether to start with seeds or clones will change the timing and manner by which your plants are introduced to the outdoors.

Plants grown from seeds are typically heartier and more vigorous than clones, as they produce a sturdier taproot that clones are not able to replicate. The vigor that comes from deep roots can be an advantage when dealing with harsh environmental conditions and pest pressures. The disadvantages of growing seeds are the additional attention required to germinate the seeds, the necessity to eliminate any males before they pollinate the females, and the high variability in growth characteristics that results from their genes.

Plants grown from seeds are typically heartier and more vigorous than clones, as they produce a sturdier taproot that clones are not able to replicate. Photo by: Gina Coleman/Weedmaps

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If you decide to use seeds, make sure you start them about a month before you would typically start clones to give them time to germinate and adequately develop their taproot.

There are also many advantages and disadvantages of using clones. They can often be found at your local dispensary, are from a proven genetic lineage, and typically do well outdoors, making them the perfect choice for inexperienced growers. On the other hand, clones develop a fibrous root system, as opposed to the deep taproots that seeds develop. Fibrous root systems can reduce the plant’s ability to deal with environmental stress and predatory insects.

Whether using seeds or clones, many cultivators start growing their plants indoors to ensure they are not exposed to damaging weather conditions as they develop their initial root system. The plants can be transitioned outdoors when the weather and light conditions are ideal. Extending the indoor vegetative growth period can help increase yields and allow growers time to select the best plants to be moved outdoors.

Soil

Quality soil should be dark, rich in nutrients, and have a light and fluffy texture. The structure of your soil should be capable of retaining water but also allow for drainage of any excess. Organic potting soil blends from your local garden center will do just fine, but more advanced growers prefer to blend their own organic super soil from scratch. The soil itself should be slightly acidic with a pH of around 6. This can be tested with a soil pH meter or test kit.

Container gardens can be convenient as they can be moved around the garden to maximize sunlight or protect them from harsh conditions Photo by: Gina Coleman/Weedmaps

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Containers vs. in-ground

Container gardens can be convenient as plants can be moved around the garden to maximize sunlight or protect them from harsh conditions such as rain, heavy winds, or extreme temperatures.

Avoid clay pots as they can be costly, heavy, and retain heat that could dry out the plant’s soil and roots. Fabric pots are the least expensive and most effective solution, as they allow for ample drainage and plenty of oxygen to get to the roots. Plastic containers are also light and inexpensive but tend to retain more heat than fabric pots. Flowering plants need a container that is at least 5 gallons (18.9 liters) to prevent them from outgrowing their containers and becoming rootbound.

Planting directly into the ground or a raised bed requires a bit more preparation but has its benefits as well. Without a container to restrict growth, roots can grow deep and thick to support a strong plant. The added surface area also allows the plant to access a greater quantity of nutrients and water in the soil, compared with a container garden. The major downside is that the plants cannot be moved and could require additional structures to protect them in the case of extreme weather.

Nutrients

Cannabis requires more nutrients than many of the other plants you may have in your garden. Quality soil contains enough organic nutrients to start the growth cycle, but as your cannabis plant grows and transitions into flowering, it may deplete the available nutrients and require additional fertilizers.

The three primary nutrients required for cultivating marijuana are nitrogen, phosphorus, and potassium.

During the vegetative phase, plants need more nitrogen in order to create the roots and leaves that serve as the base for flowering. During the start of the flowering cycle, the plants will require more phosphorus and potassium than nitrogen. Towards the end of the flowering cycle, once the majority of the nitrogen has been depleted, the plants will focus their attention on using the remaining nutrients. The lack of nitrogen is largely responsible for the vibrant purple and orange hues that can be seen on large fan leaves and throughout the plants’ colas.

Avoid all-in-one fertilizers as they can be too high in nitrogen for the flowering cycle and damage any beneficial microorganisms that may be present in the soil. Instead, choose a line of nutrients created specifically for cannabis, and use its suggested feeding charts to avoid over- or under-feeding. Organic sources of nutrients are best, as they are a great source of beneficial microbes, but they may take longer to break down and become available to the plant. Both types of nutrients can be found in dry, pre-blended powders or liquid emulsions, but can also be made from scratch with the right ingredients. Organic compost tea, which includes nutrient-rich ingredients, like molasses and earthworm casting compost, is a popular homemade brew for cannabis farmers.

Organic sources of nutrients include alfalfa meal, bone meal, kelp meal, bat guano, fish emulsion, dolomite, and earthworm castings. Each contains different ratios of nutrients that can be used for different phases of the plants’ growth cycle.

Water

The amount of water a plant needs largely depends on its size, the size of its container, the soil type, and general environmental conditions such as the weather and the intensity of the sun. Larger plants in warmer environments tend to use more water than smaller plants in cooler weather. The amount of water needed will change throughout a plant’s life cycle.

During the vegetative stage, water your plants thoroughly, then not again until the top 1 inch (2.54 centimeters) of soil has dried out. This can be every day or every four days, depending on conditions, but the time between watering will become shorter as the plant grows its roots. Container gardens tend to dry out faster than soil beds, so they’ll need to be watered more frequently.

Wilting plants and dry soil are a direct sign that plants need water. Droopy leaves along with wet soil are a sign of overwatering. Both are common mistakes and can be avoided with some practice.

For a small garden, hand-watering is the easiest, cheapest way to go. It also allows you to get familiar with each cultivar’s needs, and gives each plant the exact amount of water it requires. Irrigation systems can be convenient for a large number of plants or for times when you cannot be in your garden.

Pest and weed control

Pests and wild plants are an inevitable occurrence when cultivating cannabis outdoors. Most issues can be avoided with proper planning. Clearing a buffer area around your plants can go a long way, but your first line of defense is a healthy plant that can defend itself naturally.

Pests come in many forms, from large deer and gophers to small slugs and spider mites. Larger animals and pets can be kept out of the garden with fencing, while gopher wire beneath your soil beds can keep rats and gophers from eating the plants’ roots. Weeds will not damage cannabis, but they will compete for the nutrients in the soil and reduce the quality and yield of your crops. A light layer of mulch on top of your soil can prevent weeds from sprouting in the middle of your plants’ cycle.

Avoid spraying synthetic insecticides on your cannabis plants as further research is needed to determine the health effects of smoking plants treated with synthetic chemicals. Organic pesticide and insecticide solutions can be effective if used properly. If you can avoid it, it is always best to not spray anything on your plants while they are flowering.

Beneficial insects, fungi, and bacteria can also be used to protect your plants from their parasitic or predatory counterparts. Jumping spiders, ladybugs, and other native, beneficial predatory insects can clear your crop of insects such as aphids and whiteflies. When sourcing beneficial insects, fungi, or bacteria, it’s important to research those which are native to your region.

Security

Even if it is legal to grow cannabis outdoors where you live, you should still take some precautions to hide the plants from public view. And it’s often required by law. You can grow your cannabis plants among other plants in your garden to hide them in plain sight. Cannabis can easily grow taller than your average fence, though. Training techniques can help keep your plants shorter. The fewer people who know you are growing cannabis, the better. The ideal situation is to have your grow tucked away on a piece of land where your plants can truly flourish away from prying eyes and nosy neighbors.

Greenhouse basics

Greenhouses can be a great middle ground between the complexities of an indoor setup and the uncertainty of growing outdoors. They provide ample protection from the elements and use far fewer resources than an indoor grow. Greenhouses can be more costly than an outdoor garden and require more planning, but they also allow you to extend the growing season considerably.

Greenhouses also offer growers the ability to harvest more than once per year, if they are equipped with a light deprivation system. These systems allow growers to control the hours of sunlight their plants receive, much like turning lights on and off in an indoor garden, by covering the greenhouse with a black tarp that deprives the plants of sunlight.

Greenhouse structures range from inexpensive polyvinyl chloride (PVC) tubes, often called “hoop houses,” to highly engineered, fully automated, and purpose-built steel greenhouses. Due to their efficiency, greenhouses are quickly becoming the preferred growing method for many large-scale cultivators.

Final thoughts on successfully growing cannabis outdoors

Keep this info in mind as you embark on your cannabis-growing adventure. The smallest adjustments can make all the difference — planting a week earlier, a week later, watering less, watering more, etc.

Quality soil is crucial to the success of your crop and one of the few factors that you have control over when growing outdoors.

Timing is key. A short vegetative phase can cause cannabis plants to flower early, while a long vegetative phase can prevent your plants from finishing their flowering cycle if the weather takes a turn for the worse. The Farmer’s Almanac is a reliable source for planning around the seasons and preparing your crop for success.

Practice makes perfect, so always keep a grow journal and make sure to record any mistakes and wins along the way. Maintaining a record can help ensure you will have successful future harvests.