F1 Cannabis Seeds

Find out the fast flowering weed seeds, just 45 days to flowering, 6 weeks (F1 Fast Version) to buy online. 24H shipments! Free Gift. Offers. Cheap. Successful crosses inherit the best traits from their parents. Let's discuss what F1, F2, F3 etc selections are. When discussing seeds, you may have heard the terms F1, F2, F3 and so on yet may never have truly understood what these mean as far as breeding and lineage is concerne…

F1 Fast Version® seeds

F1 Fast Version® strains are 100% photoperiod-dependent versions featuring ultra-fast flowering of some of the most appreciated genetics from the Sweet Seeds® genetic collection. These new genetics are F1 hybrids. When grown indoors, these marijuana plants are ready to harvest just 6 or 7 weeks after the photoperiod switch to 12 hours of light and 12 hours of darkness. When grown outdoors, the plants anticipate harvest for about 1 to 2 weeks regarding to their original versions.

Gorilla Sherbet F1 Fast Version®

Big Devil F1 Fast Version®

Black Jack F1 Fast Version®

Cream Caramel F1 Fast Version®

Cream Mandarine F1 Fast Version®

Crystal Candy F1 Fast Version®

Gorilla Girl F1 Fast Version®

Green Poison F1 Fast Version®

Jack 47 F1 Fast Version®

Killer Kush F1 Fast Version®

Red Mandarine F1 Fast Version®

S.A.D. Sweet Afgani Delicious F1 Fast Version®

Sweet Cheese F1 Fast Version®

Sweet Skunk F1 Fast Version®

Tropicanna Poison F1 Fast Version®

Due to their fast flowering, these strains are very appropriate for growing in humid and rainy zones, in high mountains or regions with cold winters. In these areas that are especially sensitive to fungus attacks, these strains are very adequate because they manage to anticipate harvest to the season when the most virulent botrytis (grey mold) attacks, decimating the buds of the plants that feature longer flowering periods.

What are F1 Fast Version® strains?

Photoperiod-dependent strains are genetics that flower according to the photoperiod (the hours of light and darkness that plants are subjected to).

F1 Hybrids are the first resulting generation of the hybridization between two different and stable varieties. They combine the valued “stability” and also the appreciated “hybrid vigor” in the same generation. The more stable (homozygotes) the parentals and the larger the genetic distance between both of them, the greater this “hybrid vigor” and “stability” is.

The F1 Fast Version® strains are the first filial generation (F1) resulting from the cross between a photoperiod-dependent genetic and an autoflowering genetic. The result of this hybridization between two stable and totally different plants (at least regarding the type of flowering) is known in genetic terminology as “F1 Hybrid”. The F1 Fast Version® strains are hybrid genetics, 100% photoperiod dependent and featuring a very fast flowering stage.

The photoperiod-dependent parental contributes with its photoperiod-dependent trait to the F1 Hybrid in all the offspring. This happens because the photoperiod-dependent characteristic is dominant regarding to the autoflowering characteristic that, on the other hand, is recessive.

The autoflowering parental contributes with a very fast flowering and maturation of the flowers to the Hybrid F1 in all its offspring. In this case the heredity is in a half-way point and the autoflowering genetic reduces the duration of the flowering stage of the photoperiod-dependent parental in between 1 and 2 weeks.

At Sweet Seeds® we have used this type of hybridization that leads for a reduction in the flowering time in some of the most appreciated genetics from our catalog, creating versions with a very-fast flowering of some of our most appreciated photoperiod-dependent genetics.

Sweet Seeds® was the first feminized marihuana seed bank that released this type of hybrid genetics in the market. They are available in the cannabic scene from 2013.

What makes F1 Fast Version® strains so fast in flowering?

The fast flowering of our F1 Fast Version® genetics is mainly due to the type of autoflowering genetics that intervene in the cross. At Sweet Seeds® we select the fastest-flowering autoflowering genetics for the production of these photoperiod-dependent strains featuring fast flowering.

There are a lot of types of autoflowering genetics regarding the duration of their life cycle. Some autoflowering genetics may even need 4 months to complete their life cycle, with a flowering stage that may be of up to 2 months. At Sweet Seeds® we have always avoided to work with autoflowering genetics that feature long life cycles. The autoflowering genetics from our catalog feature a very short life cycle (from the appearance of the cotyledons till harvest), of between 7 and 9 weeks, with a flowering stage of between 4 and a half and 6 weeks. Obtaining very productive autoflowering strains that are resinous, aromatic and, at the same time, fast, is the result of long massal selection programs in successive generations.

The autoflowering specimens with the shorter flowering stage are selected for the production of F1 Fast Version® strains. These select autoflowering genetics featuring very fast flowering provide to the F1 Hybrid a very fast flowering in all the offspring when compared to the photoperiod-dependent parental.

Advantages of F1 Fast Version® genetics

Growing these strains allows for keeping all the advantages of the photoperiod-dependent varieties, such as:

One of the main advantages of growing with photoperiod-dependent seeds is the possibility of preserving, for an indefinite time, clones of any special plant that we find. This can be done by keeping the clones with artificial lights in a photoperiod of 18 hours of light and 6 hours of darkness. With this light cycle the Mother Plants keep in the vegetative stage without ever getting into the flowering stage and they can be used to produce clones.

These photoperiod-dependent plants can be multiplied in our garden by taking clones from our plant from seed or from our mother plant.

Keeping photoperiod-dependent plants with a vegetative photoperiod, for as long as we wish, we can control the height and size of the plants to obtain big sized plants and high production of buds. In outdoor growing, this allows us to get enough stock for our annual consumption with just a few plants. In the same way, controlling the photoperiod in order to induce the flowering without any vegetative growth, we can obtain the opposite effect: small and discreet plants with a fast life cycle. To plan the desired height in advance, we will have to take in consideration that, depending on the strain, the plants may double or even quadruple the height presented in the beginning of the flowering stage or since we start the change in the photoperiod in indoor grows.

Besides the previously mentioned advantages that are shared by all the photoperiod-dependent strains, the fast flowering of the F1 Fast Version® genetics allows for extra advantages for the cannabis growers:

  • Savings in the time spent in the grow:

The duration of our grows is very important. With this type of genetics we will be able to enjoy our weed a few weeks earlier.

A very important detail for indoor growing with artificial lights, taking in consideration the prices of electricity and the contamination that it takes to produce electricity.

If we harvest a few weeks before, we will consequently dedicate less time to taking care of our plants. We can dedicate this time to other hobbies and to enjoy our harvest.

With a shorter flowering time we will also consequently use less flowering nutrients.

  • Allowing to anticipate harvest to fungus attacks and to the cold and rainy weather:

This is one of the most important advantages of F1 Fast Version® genetics. This advantage can be a particular benefit for outdoor growers from humid and rainy areas, high mountain zones or regions with harsh winters. Fast-flowering marihuana plants can anticipate harvest to the most virulent season of fungus attacks, that decimate the buds in long time flowering plants. It also allows for an anticipation to the arrival of bad weather and the cold. These genetics are ready to harvest between late August and early September in the Northern Hemisphere. Late February to early March in the South Hemisphere.

  • Strong presence of the Hybrid Vigor or Heterosis:
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As they are F1 Hybrids, they feature strong hybrid vigor. The hybrid vigor phenomenon is normally expressed in a quantitative way. This means that they are measurable and in marihuana they are usually expressed as:

  • Increase in production.
  • Better adaptation to the environment.
  • Greater resistance to plagues and disease.
  • Greater tolerance to environmental stress.
  • Increase in the growth speed.
  • Greater precocity (reduction in the time needed to achieve maturity).
  • Increase in the general size of the buds, stems, leaves, etc.
  • Increase in the total number of nodes, leaves, flowers, trichomes, etc.
  • Increase of the amount of terpenes and cannabinoids.

Not all the vegetable species feature the hybrid vigor phenomenon, although it is very frequent in the vegetable kingdom and it is expressed with greater intensity in allogamous species, which is the case of marihuana. The wider the distance between the parentals, the greater the hybrid vigor.

As they are F1 Hybrids, these genetics show great stability. This is a very sought trait by all the growers. Even more when this stability is shown in characteristics that are desired and sought by the cannabis grower.

Breeding and inheritance in F1 Fast Version® strains

For the development of the F1 Fast Version® genetics we use the best selected autoflowering strains and the collection of elite clones from the Sweet Seeds® bank of mothers.

The autoflowering or photoperiod trait is dependent on a single gene. This gene presents two possible alleles. One is dominant (F), which is the one that codifies the photoperiod character while the other one is recessive (a) and is the one that codifies the autoflowering character. As the allele that codifies the autoflowering character is recessive, to express this type of flowering it is required to be in a state of homozygosis, which means that all the autoflowering plants are (aa), as they have received a gene (a) from the father and another one from the mother.

On the other hand, every photoperiod strains (elite clones) of the Sweet Seeds® bank of mothers that we use to produce F1 Fast Version® strains are homozygotic for the dominant character that expresses the photoperiod-dependent flowering. They are (FF) as they have received a (F) gene from the father and another one from the mother and this is something that we can deduce from the analysis of the offspring of these clones.

The first resulting generation of the cross between these two types of strains –photoperiod (FF) and autoflowering (aa) –, obeying to the first Mendel Law or to the Hybrids Uniformity Law for the first filial generation, provides as a result a 100% of hybrid specimens (Fa) and as (a) is recessive and (F) is dominant, 100% of the population is photoperiod dependent and zero autoflowering plants show up. This first hybrid generation between homozygotes for one or multiple characters in the genetic line is known as F1 Hybrid.

As it refers to a F1 seed, if we cross these seeds (Fa) with each other to obtain more seeds, then the second generation, known as F2, concurring with the second Mendel Law or Character Segregation Law for the second filial generation, will not produce 100% Fast Version (Fa) specimens anymore. Within the specimens originated from this procedure, we would obtain a mix of 25% autoflowering (aa), 25% photoperiod (FF) and 50% Fast Version (Fa). The only generation that is 100% Fast Version (Fa) is the F1 Fast Version®.

Discovery of the F1 Fast Version® strains. The beginning

At Sweet Seeds® we have been one of the feminized marihuana seed banks pioneer in the development of autoflowering genetics. And the first seed bank in the world to offer F1 Fast Version® genetics to cannabis growers.

Around the year of 2007 at Sweet Seeds® we started our programs to introduce the autoflowering gene in our most appreciated elite clones, with the final goal of obtaining equally exquisite genetics but in autoflowering version.

When we performed the first crosses between autoflowering genetic lines and our beloved photoperiod-dependent elite clones, we observed that 100% of the first generation was photoperiod-dependent. There was not one single autoflowering specimen. This was something expectable and indicated that the autoflowering character was recessive and the photoperiod-dependent character was dominant. But what really called to our attention in our first experiment was how fast the F1 Hybrid flowered. We even double checked our calendars to be sure that there were no mistakes in our annotations. We confirmed that there were no errors whatsoever. The cross with the autoflowering strain leaded to an important shortening in the flowering time to the F1 Hybrid and bud maturation happened about 2 weeks earlier.

This new experiment was repeated each time that we wanted to develop a new autoflowering strain through hybridization between our best autoflowering genetic lines and elite clones from our bank of mothers. The successive experiments confirmed that the resulting F1 Hybrid from these crosses featured a much faster flowering than the photoperiod-dependent parental.

What are F1 Seeds? What about F2, F3, etc?

Breeders often devote their entire careers to creating that one perfect cross. They achieve this by enhancing the strongest properties through selection and crossbreeding. These crosses are indicated by generation.

Let’s discuss what F1, F2, F3, etc selections are.

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  • What are hybrid cannabis strains?
  • What are f1, f2, f3, etc. selections?
  • Creating new cannabis strains
  • Pure breeding line or strain
  • Creating a stable f1 strain
  • Let’s recap.

What are hybrid cannabis strains?

The demand for new cannabis species is increasing with the natural consequence that there is plenty of experimentation by breeders.

As a result of this (cross) breeding and experimenting, most of the species on the current commercial market are hybrids. These are plants that are a result of crossbreeding several cannabis varieties to amplify certain effects or characteristics.

As this crossing process evolves, the plants will eventually form seeds from different cannabis strains or generations.

Cannabis, like any other plant, exists as a pure variety or as a hybrid mix of strains.

Hybrids are the result of attempts to shape plants with specific characteristics, which are common in ruderalis, Sativa, and Indica strains. Successful crosses inherit the best traits of both parents.

When the industry started to commercialize, both pure varieties and existing hybrids were constantly mixed and recombined. These efforts have produced some of the best-known species today.

What are F1, F2, F3, etc. selections?

As you further specialize in cannabis cultivation, you will undoubtedly encounter more and more impressive terminology.

When I first saw the term “F1 strain”, I seriously wondered what car racing and cannabis have to do with each other (and if it was wise to combine the two).

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Needless to say, the guys got a good laugh out of that one. It turns out it has nothing to do with the automotive sports industry, nor should we fear for Hamilton’s safety.

In this case, F1 means something totally different and very fascinating!

In a nutshell, an F1 variety is the first hybrid plant from a specific pair of parents and a new phenotype that is
independent, yet still closely related to the two parents.

But that just sounds confusing and doesn’t cover the load. Let’s go further back first before we take a leap into the unknown.

Creating new cannabis strains

The basics of growing plants are always the same. This also applies to cannabis. Male pollen pollinates the female plant. Nature has ensured this happens naturally.

But when creating a hybrid, the growers use selective breeding in a controlled environment. This entails that the breeder personally selects the female plant and the male pollen in order to get one or more specific characteristics in the offspring.

A few of the properties that can be improved through selection are rooting, growth potential, flowering period, color, bud structure, and yield.

The seeds germinated after this process are the first generation of hybrids from male and female parents. The plants with the desired characteristics undergo this selective process again.

Once the desired traits are achieved, the breeder stabilizes the species.

The next step is crossing the young hybrid with the parent species to enhance the characteristics.

This process requires a lot of patience and perseverance from the breeder since stabilizing the properties of a species usually requires three or more generations.

We distinguish the following generations:

To make a well-informed decision when deciding on what the ideal seeds for you, it is helpful to understand the differences between these different generations.

Pure-breeding line or strain

A group of identical individual plants that always produce offspring of the same phenotype when intercrossed.

Pure-breeds are unadulterated traditional landraces that have only interbred with similar strains and so have almost identical genes.

F1 – The first grow

F1 stands for “first-generation hybrid”. The F derives from Filius, which is the Latin word for “son”. Yes, botanists sure love their Latin 😉

You create an F1 strain by crossing two pure strains with completely different phenotypes. To achieve this, the grower will, for example, take 100 of their best plants and select only the very best mother plants based on a specific trait from one strain.

He will do the same with another (pure) species.

Let’s take a large plant (represented by two dominant genes, AA)
and cross it with a small but bushy plant (represented by the two
small recessive genes, aa). Since the resulting plants each receive
one gene from each parent, this will result in offspring with the following genetic makeup: Aa. All four offspring have the same makeup and will each be tall bushy plants.

The difference from the parent generation, in this case, is that these will not be pure strains due to the presence of the recessive gene.

F2 – Keep on crossing

To create an F2 strain, the breeder will cross two members of the F1 family together.

The offspring that comes from this crossing has
the genetic makeup of AA, Aa, AA, and aa.

That means that the F2 seed variety will have three tall plants and one short plant. So, the main difference between the F1 and F2 varieties is the amount of genetic variation and purity of the seed strain.

F3 – Reducing variation

As the cycle continues, we keep combining plants with the desired traits. We call this generation: F3. For example, if the grower was looking for short plants, he would select parents with the composition of Aa and aa.

The result of this combination is two tall plants, each with the genetic markers of Aa, and two short plants (both aa). This breeding has actually reduced the variation towards a more stable variety. We call this process stabilizing.

Since F3 varieties usually start of rather unable we advise to cross it back with the selected F2 mother plant.

F4 – Narrowing the number of phenotypes

Once you’ve achieved a level of stability in your F3 variety, it is time to take your game to the next level. By continuing the selection process and using only the most stable plants from the previous generation, we’ve now reached the F4 variety.

F4 varieties contain even fewer phenotypes, which means that the plants should be nearly identical, with only slight variations in, for example, scent or yield.

F5 – Perfecting the process

By continuing on this path of crossing the strongest plants back within their own generation, the stability grows and a strong new species has emerged.

IBL Strains

After F5, the plants are IBL.

IBL stands for “inbred line”, AKA the holy grail of cannabis cultivation.

An IBL is a breed that produces offspring with stable and consistent genetics usually from a single dominant phenotype of the strain.

These strains will produce balanced and homogenous offspring with the desired specific characteristics time and time again for many generations.

Creating a stable F1 strain

When you pollinate a feminized female plant with pollen of the male-cannabis plant, you will get seeds, but not automatically a stable strain.

Breeders create stabilized hybrids and then continually interbreed, stabilizing their characteristics from generation to generation.

There are very few strains of stabilized hybrids as the process takes a number of generations, over several years, to achieve.

It is important to note that ‘stable’ is not the same as ‘true-breeding’. A true-breeding strain will produce consistent offspring of one dominant phenotype. In marijuana strains, you can mainly find this in landraces.

If you want to create a stable strain that shows the generation of the same characteristic after generation, you will have to stabilize it by crossing it back various times. By always selecting and crossing plants with the desired characteristics, you stabilize a species.

Since this is a time-consuming technical process that demands a lot from the breeder, it’s now clear where the -sometimes- massive price difference for different types of seeds comes from.

Let’s recap.

F1 is the result of crossing 2 separate varieties. The resulting seeds are F1 and they will be stable, meaning the plant qualities should be pretty consistent.

All the plants from these seeds will be very similar. This is great if you prefer a crop of identical plants.

F2 is a cross of 2 of your F1 plants from the seeds you bred. F2 is what true breeders are looking for.

The F2 seeds are unstable meaning the plants grown can show very different qualities, some may be good while others are bad. The F2 seeds can contain all the possibilities of phenotypes from all of the previous lineages of both parents.

F2’s are where you will find the next great strains which is what true breeders are consistently trying to do along with producing stable seeds for its consumers.

Once you find that special F2 plant, you need to cross it with another F2 from the same seed batch. Next, cross this plant back with your special F2. The seeds from this, called F3 will be unstable and may not produce your special F2 consistently.

To stabilize your new strain (The special F2 plant you selected) you now grow F3 seeds and pick one of these to back cross with your F2 mother.

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The resulting seeds from this will be an F4 and more stable than F3 seeds. You continue this process to about an F5. By this time the F5 seeds should be stable and look like the new breed F2 that you found. You have now created your very own new strain!

So the main difference between F1, F2, and F3, etc. is simply the generation and level of stability that comes with them.

With each successive selection, the grower selectively takes the plants that are the best representation of the properties he desires and uses them for crossings.

I hope this has given you some insight and clarity and brought you are one step closer to being a full-fledged Marijuana high school graduate. Happy growing


Educated by one of the best breeders in the Netherlands, I chose to combine my passion for writing with the fascinating world of cannabis cultivation. What are the best strains for which occasion, what are the effects, and how to use responsibly? Let me take you on a journey.

Breeding For Success – How To Make F1 Seeds With Regular Seeds

When discussing seeds, you may have heard the terms F1, F2, F3 and so on yet may never have truly understood what these mean as far as breeding and lineage is concerned. Below is better explained how to make first generation seeds and what you need to know.

By Stoney Tark

What Does First Generation Mean?

F1 stands for first generation lineage, and represents the offspring created by the original mother and father. The term is also an expression of a hybrid made using regular seeds. Female seeds are referred to as S1 and involve a completely different process than working with regular stock.

Desired Traits Over Non Desired Traits

Before you begin a breeding project, you should always plan ahead and think of the real reason you are attempting to make a new strain in the first place, or at least a first generation cross that may be more dominant of a certain phenotype you desire. The different characteristics that a breeder may wish to focus on are growth structure, leaf pattern, flowering time, wind resistance, aroma, effect, resistance to pests and bugs, as well as resistance to plant disease and pathogens.

Matching plants together that are more compatible based on the above, is one way to promote hybrid vigour without too much variation when sifting through a large number of plants. If you are breeding for commercial reasons and plan to make a certain strain a bigger producer, or narrow the flowering time down to better fit in with the maximum number of growing cycles in a year, then the main characteristics can be down to how the plants look visually, instead of more hands on and actually testing each flower during the phenotype hunting.

What Should I look For?

Once you have established the end result on paper and what traits you are bringing forward, then the way to sift through your regular seeds should be to look for those traits in the plants you will select from. Some breeders may only be able to work with a small space and growing over 20+ seeds at a time to find one keeper is not practical or logistical.

If you already have decided which female is the best plant in your grow room, then the stage of smoking all the potential females and testing each for quality, quantity, flavour, appearance, aroma, taste, effect, bag appeal,terpene profiles and cannabinoid profiles is not required. Otherwise this is the part where you can discover what is special and worth keeping, and which phenotypes do not express the characteristics you are looking for.

Step By Step Guide


This guide is written on the basis that we are crossing two different strains with one another, to make a new variety. Starting with regular seeds you will label each seedling to make the catalogue process simple and easy from the very start. You will be looking for a particular female that aligns with your criteria, as well as looking for male plants that from appearance, look similar in height, structure, leaf pattern and so on.


By growing the plants under a vegetative cycle of 18/6, you will now wait until the point of the plants revealing their sex. This is usually after the 5th week of the growing stage, as male plants can often show male preflowers before female plants. Take clones of the numbered plants and number the clones the same. This way you can keep on producing more seeds without losing the original male and female.


Begin to flower the plants and over this next 7-10 days, the plants will show their pre-flowers and you will be able to clearly see which of your regular seeds are male and female. This is the stage where you can identify by eye which plants will be keepers based on appearance alone.


Isolate the male plants from the females and label the plant dependant on the sex. At this point you will want to select the females you find the most appealing and pair them off with the male that you have chosen. If you have multiple males you will either need a second tent to perform the breeding process, or you must wait until the first male has flowered and begin new with a clean and sanitized room, at a later date.


Allow the male pollen to reach the pistils of the female plants. This process only takes a moment to happen, which will be indicated by the white hair turning marron brown almost instantly. Successfully pollinating can be done by hand or in an open room. From this point on, the hard work is done and now the plants will spend all their energy, producing strong, viable seeds.


Harvesting the seeds should be done with a professional approach with correct labelling. If you are producing a small batch of seeds for testing reasons, or aiming for thousands of seeds then make sure you have labelled the final storage bag with what male was used with what female. When reproducing first generation lineage, you must have an identical copy of the original stock that was used, otherwise compatibility and variation may differ.


Test the new F1 seedlings that you have made, with the mindset of mass producing them with the clones you have of the original mother and father. Once you are happy with the germination rates, stability of the plants, quality of flower and all of the other important factors, then you can now replicate another breeding room using a large number of female clones with the father.

What to consider: If you are unable to keep genetic copies of the original father or mother used, it is not possible to replicate that same lineage. The closest you could get is to make a F2 which is second generation cross. Here is where the most desired traits and the most undesired traits will express themselves. In terms of phenotype hunting, this can be more complicated that creating a more homogenous and stable line. Try and keep your genetic copies alive and easily accessible as it is the difference in regenerating that genetic replica.