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Preflowering And Flowering

THE END OF VEGETATIVE GROWTH

By now you have managed to set up the basic environment in which your indoor plant will grow. You have your plants in some pots under a grow light with some white surfaces nearby and some fresh air in the room. You have also been watering your plant properly and you have been adjusting the pH and Nutrients in the soil.

Everyone makes mistakes on their first time growing. Very few get to this stage without problems, so don’t feel too bad if you did not get it right. Growing marijuana is like riding a bike. Once you get it, it is hard to forget.

You have been adjusting your lights and watching your plants grow. If you have not had any problems your plants should have a number of nodes and a small leaf mass at the top of your plant which you know is going to form the next set of leaves and branches.

Your leaves should be flat and stretched out. If they are, then your plant is enjoying its environment. If not then maybe you should consider turning to our problem solver chapter to see what has gone wrong.

You have been watching the height of your plant every week and now the plant is becoming more like the picture of the strain that you viewed in the seed-bank brochures. Then one day you notice that the plant is not growing much taller anymore. It seems to have stopped. You take a closer look and see that there appears to be small new growths at most of the nodes between the stem and the branch. This is new to you. These have not developed before so you ask yourself, “what are they?”

Your plant is now reaching the end of its vegetative stage. These small new growths are going to produce more leaf, branches and FLOWERS. The plant is now entering its Pre-flowering stage.

PRE-FLOWERING

Now is the time when you should be hoping for as many females as possible and that all your work has not been in vain. You closely look at the new growths (Calyx) to see if you can identify your plants sex, but it is still too early to tell.

The early stages all look the same you say? What should you do now? You do not know? You will have to wait and see.

There are three things that can reveal your plant’s sex early on but these are not 100% accurate. They are more of an educated guess. So remember these methods can fail to be accurate but most of the time they are a good indicator.

First Early Sexing Method:

If you have been growing the same strain and all the seeds at the same time, then you may notice that some plants are taller than others. This is a sign that the smaller plants are female and the taller ones are male.

If you want too, you can separate your plants into two sections in order to see how good your guesswork was when you do finally identify sex. The other thing to know is that male plants in general start to pre-flower before females. If you have taller plants that are producing new growths before the smaller ones, then the taller plants are probably male.

Second Early Sexing Method.

A good way to identify plant sex at early date is to look at the calyx with the aid of a very fine magnifying glass. (See last page of this book for pre-flowering/calyx illustration)

If the calyx is raised on a stem then it is probably a male. If the calyx is not raised on a stem then it is probably a female.

Third Early Sexing Method.

Force-flowering a cutting is probably the best early sexing method out there. Simply take a cutting from the plant that you want to sex and place the cutting in a cup of water or into a cloning medium such as rockwool. Give the cutting 12 hours light and 12 hours total darkness. The cutting will flower and display its sex. Clones will carry the exact same genetic make-up as the plant it came from, including sex.

These methods are NOT 100% accurate but will help you to understand more about the visible differences between male and female plants. In a moment we will explain how to identify sex properly and completely.

THE PRE-FLOWERING TIME

Your plant will Pre-flower between 1 and 2 weeks and during this period the new growth regions begin to change shape depending on whether the plant is male or female. It is during this shape change that you can properly detect your plant’s sex.

Pre-flowering is a sign that your plant is mature enough to start flowering. As a grower you have a simple choice to make. Do you want to flower now? Or do you want to continue vegetative growth? Here are a few facts before you make that choice.

– Most cannabis plants can be kept alive for up to 10 years by simply keeping a light on the plant at all times. These plants will grow to a certain height and then form into a bush. It will then eventually stop producing branches and will spend the rest of its life growing new leaves to replace the old ones.

– Bud production is not equal to the height of your plant. Bud production is equal to your growing environment, your strain’s genetic make-up and the amount of nodes that the plant has. All nodes are potential bud areas, but every strain has a genetic threshold for bud production.

– It possible to get more bud with lots of plants which are flowered as soon as they are mature (which also keeps them shorter and smaller), than extending vegetative growth with less plants until they reach their maximum height and size. The time frame for the shorter option may also produce more bud turnover per annum.

Figure 7.1 – A Picture of a large indoor grow by

Figure 7.1 – A Picture of a large indoor grow by

Vic High.

Keeping these things in mind, you can either choose to flower now or choose to keep your plant growing until it reaches its size threshold before you start flowering. If you take the longer route then prepare to have the space for it, because when you flower most cannabis strains they can sometimes more than double in height and width.

If you have pre-flowers and want to flower you only have to do one thing. You must put your plants under a 12/12 schedule.

Figure 7.2 – A Picture of an indoor grow by

Figure 7.2 – A Picture of an indoor grow by

THE ALL-IMPORTANT 12/12!

Most people never get good results or bud quantities from cannabis plants because they have never heard of 12/12.

12/12 is easy to explain. Cannabis plants grow outdoors naturally between the months of April to October/November. This means that towards the Sept/Oct/Nov dates the plants will be in flowering. During this time the days get shorter and the nights get longer. When this occurs the plant is under 12 hours of light and 12 hours of darkness. When this 12/12 PHOTOPERIOD occurs the plant is naturally stimulated to flower. If the 12/12 continues then the plant will produce its flowers. As long as 12/12 continues the flowers will grow larger and more plentiful. This is part of the cannabis plants evolution and how it has taught itself when to flower. Naturally as a grower we want lots of flowers so we need to put the plant through a light cycle of 12/12. This means that we must turn our lights on and off at these given ratios.

During pre-flowering you will either manually turn on your lights for 12 hours and turn off your light for 12 hours everyday or you will use an automatic timer. If your light comes with a timer set the timer to do this. Throughout the 12 hours of darkness it is best to keep your grow area as dark a possible. A small desk light at the other side of your room will cause your plant not to react properly to 12/12 which will result in continued vegetative growth. In fact any light that penetrates the darkness will stop your plants from flowering properly. That means that your grow room must be sealed to the point where it is completely light proof. If you want to learn how to do this perfectly then I suggest that you read up on ‘Photography Dark Rooms’, either on the Internet or in your local library.

Photographers use common items that can be bought in most hardware shops to make their film-processing rooms light tight. If you can replicate their ideas (basically a thick black screening around the doorframes or any open light points) then you will have a great system for flowering plants in. I think most of you would have done this by now anyway if you listened and took the advice on covering your grow with either Mylar or white walls/boards. If you have prevented any light from leaking out, then you have prevented light from leaking in!

Problems with 12/12

If you switch to 12/12 before pre-flowers have shown then you may encounter the following problems.

– Stress related sex problems (Hermaphrodites).

– Abnormal bud growth.

Stress related sex problems MIGHT produce hermaphrodite plants. The stress of what is sometimes called “early flowering” (it is not really early flowering, there is no such thing as early flowering. We will explain this in a moment) triggers the plant into a situation where it thinks that its chances of reproduction are slim to none. That situation is a condition called – ‘self-pollination’. It does this by producing both male and female flowers on the same plant. The male flowers then pollinate the female flowers which will eventually produce seeds. The reason for this is that the plant notices that the photoperiod is irregular and that it should no longer be in the vegetative cycle but in flowering. This shocks the plant into a last ditch effort to receive pollen because it feels that it has missed its chance to receive pollen already (in the wild males release their pollen just around the time that females begin to flower and sometimes even before that).

Figure 7.3 – This is what hermies look like. Notice that both male pollen pods and female pistils are present on the plant. Picture by Rasta Linus.

Figure 7.4 – Here is another shot of the condition. The male pods are clearly visible.

Figure 7.4 – Here is another shot of the condition. The male pods are clearly visible.

Figure 7.5 – These series of shots also show the hermie condition clearly. Picture by Tick.

Hermies cause problems because they may carry the hermie trait with their offspring. In fact, genetically the hermie will only produce female seeds and hermaphrodite seeds. It will never produce a male seed. If you have ever seen all female seeds been advertised by seed-banks then you should have the right to know that these seeds come from female plants which are stressed into producing male flowers. The plants then self-pollinate themselves and the results are female and hermaphrodite seeds. In a special case a female known as an XX female will produce more female seeds than hermaphrodite seeds. That is how female seeds are created. In general growers try to keep away from any hermie plants because they will spoil a Sinsemilla crop. Also having pollen floating around in your grow room from a hermie plant will spoil everything else including breeding projects.

Abnormal bud growth is a side effect of this. Because the plant produces male pollen sacks in with female flowers you may notice that the bud looks different. Also the quantity of female bud produced is decreased because of pollination.

Early induced flowering is not technically forcing your plant to flower. If you force flower on one strain that has not pre-flowered it will flower at roughly the same time as an exact copy of the same strain which has been flowered only when the pre-flowers appear naturally. Force flowering simply acts by stressing the plant into a crisis condition.

Get the best out of your plant and wait until your plant starts pre-flowering before switching to 12/12.

Keep feeding and watering your plant as normal. Pay attention to the flowering areas as they begin to grow. At this stage you may want to switch to your flowering feeds. Soon you will be able to see your plant’s sex.

THE MALE/FEMALE THING or HOW TO SEX YOUR PLANTS

You now have spent time and money on your plants. You have grown a small selection in the hope that you will get some females out of them in the end. If you end up with no female plants out of 15 seeds then send the seed-bank a letter explaining how out of the 15 seeds 15 where male. If you are lucky and sincere in your writing then the seed-bank may send you some free seeds or give you a discount on your next order. Seed-Banks or breeders are not responsible for male/female ratios. It simply is not under their control. People get 100% females and others get 100% males, but it is rare that such a thing will happen. To get 5 or more females in a pack of 15 is a good thing.

Here are some pictures of male and female plants.

Figure 7.6 – This is a picture of a male plant. You can see the male pod clusters clearly. The picture is by the ‘Chronic Couple’.

Figure 7.6 – This is a picture of a male plant. You can see the male pod clusters clearly. The picture is by the ‘Chronic Couple’.

Figure 7.7 – This is a female plant by BigIslandBud.

Notice how the female produces little white hairs and the male produces little ball like shapes. This is the definitive male/female telltale factor. Do not kill away any plants before you see these flowers. It is the only time that you can really say for sure if the plant is male or female.

FLOWERING

If all things have gone well and you have taken good care of your plants, you will now enter the flowering stage of the plant’s life cycle. You have removed and maybe killed off the males. You now have a number of females to work with. This is going to be the most important time you will spend taking care of your plant.

The male plant produces pollen sacks which, when ripe, burst and scatter pollen to the female plants. The female plant produces white hairs at the internodes and top cola (head) of the plant during flowering. These hairs (pistils) begin to curl slightly and grow longer and thicker. The top cola should carry the most pistils. These pistils are sticky too touch (do not touch them too much! they also contain your much wanted THC) and begin to cover in resin over the flowering period. The reason for the stickiness is that it is used by the female to catch falling pollen. If the female plant is not Pollinated she will try to grow more sticky areas. Hence the results of a sinsemilla crop Bigger and Better Buds!

Figure 7.8 – Picture by BushyOlderGrower.

During the strict cycle of 12/12 she will eventually reach a peak period of flowering. Along with the flowering cycle the plant will also fill out more. More leaves, more branches and more flowers. Your plant will start to almost take the shape of a Christmas tree. The lower fan leaves will be stretched out to the max in order to receive the most light. Running upward in a cone shape she will get tighter with floral and leaf development.

During the peak period of flowering the female pistils on the flowers tips will swell up. When the swelling takes place the pistils will begin to change in colour. They will generally change from a white to an orange tint to a red tint to a brown tint. All strains are different but in general it is a white to red or a white to brown colour change (It is best to use the breeders recommended flowering times for harvest guidelines though). When she does this you are ready to harvest her and sample your favourite herb.

Each strain does have their own flowering times and each strain also may have a different colour tint when they reach a flowering peak.

We will talk more about harvesting in another chapter.

By now you have managed to set up the basic environment in which your indoor plant will grow. You have your plants in some pots under a grow light with some

Cannabis Pre-Flowers: Identify Sex of a Plant as Early as 3 Weeks Old (with pics!)

Table of Contents

  • Leaf Sample Testing (Bonus) – Identify sex in just 1-3 weeks from germination
  • Male Pre-Flower Pics – Appears 3-4 weeks from germination
  • Female Pre-Flower Pics – Appears 4-6 weeks from germination

Variability of Plant Sex (How to Increase Ratio of Female Plants)

Example of Male and Female Cannabis Pre-Flowers

The female plants will soon produce pistils. Wispy white hairs are a sure sign that you’re looking at female pre-flowers.

How to Determine the Sex of a Young Cannabis Plant

What are cannabis “pre-flowers?” They are little versions of adult flowers that appear on your marijuana plants relatively early in the vegetative stage.

When I first started growing weed, I learned (incorrectly) that there is no way to determine a cannabis plant’s sex until the flowering stage. But I’ve since learned that pre-flowers can reveal the plant’s sex while it’s still in the vegetative stage! Cannabis plants grow pre-flowers as young as 3-4 weeks from germination for male plants, and 4-6 weeks from germination for female plants.

Cannabis Pre-Flowers Are Small Versions of Adult Flowers. These reveal a plant’s sex.

Knowing the plant’s sex is helpful because most hobbyist cannabis growers would like to identify and remove male plants from the grow room early in the growing process. This is because only female plants make potent buds/flowers, while male cannabis plants make non-potent pollen sacs where female plants would grow buds. Additionally, female buds need to avoid pollen from male plants in order to make the highest quality cannabis (sinsemilla or “no seeds”).

Cannabis pre-flowers appear at the base of leaves when male plants are about 3-4 weeks old, and female plants are 4-6 weeks old.

Even if you’re not 100% sure about every plant from looking at the pre-flowers, it’s nice to know which plants you need to watch closely and which are definitely female. However, if precision is very important…

Chemical Leaf Tests Can Determine Sex & Potency for plants as young as 1-3 weeks

Chemical leaf testing is getting less expensive every day and can be used on cannabis seedlings with just a few sets of leaves to test for sex and future potency.

These tests only require a tiny amount of plant tissue (for example a small punch-out from a leaf, or a single cotyledon leaf), so it won’t hurt or slow down your seedlings to take a test sample!

In general, the tests are available for seedlings as young as 1-3 weeks. Sex testing uses a real-time polymerase chain reaction (qPCR) test, and potency tests use Gas Chromatography with a Flame Ionization Detector (GC/FID) or High-Pressure Liquid Chromatography with a Diode Array Detector (HPLC) for testing.

Although testing can be done as early as week 1 from germination, waiting until week 3 to conduct testing on seedlings can increase accuracy, and some companies won’t conduct testing until week 3.

There are many reasons growers would like to know plant sex as early as possible, as well as be able to estimate the overall THC/CBD ratios of future buds!

Did You Know? There are Chemical Leaf Tests that Can Definitively Determine Both Plant Sex & Future Cannabinoid Ratios of Very Young Marijuana Seedlings!

But for those of us using our eyes…

Male Pre-Flower

Female Pre-Flowers
(these turn into buds)

This female pre-flower hasn’t released a wispy white pistil quite yet

When starting with “feminized” seeds (which you can usually only get from a breeder), all your seeds should end up being female, so determining male from female isn’t very important. Learn more about buying seeds (including feminized seeds) from breeders online.

But for growers starting with “regular” (non-feminized) seeds, about half of the plants can turn out to be male. And unfortunately, there’s no way to look at a seed and be able to tell what sex it is.

Unfortunately, you can’t tell a cannabis plant’s sex for sure by looking at the seeds 🙁

How to Figure out Sex of a Cannabis Plant by Examining Pre-flowers

Vegetating plants usually reveal their sex when they’re just 3-6 weeks old from seed, but you have to know where to look.

What you’re looking for is “pre-flowers.” These are tiny versions of adult sex parts, and when you see them you can tell what sex the plant is going to be. They usually show up in the upper parts of the plant, closer to the lights, but sometimes you’ll search the whole plant and only find a pre-flower on a random branch lower down on the plant.

Vegetating cannabis plants reveal their sex with “pre-flowers” that usually appear 3-6 weeks from when the plant first germinated.

Although these are the general shapes of male and female pre-flowers, if you continue looking through the pictures below, you’ll see there’s quite a bit of variation on what pre-flowers look like from strain to strain.

Most male plants have grown a pre-flower by week 3-4 from seed, while female plants don’t show until week 4-6. Basically, all vegetative plants will have revealed their sex by about the 6th week from seed.

So, without further ado, here are pictures showing what you’re looking for when it comes to pre-flowers. Remember, pre-flowers are found at the V where stems meet a main stalk. But pre-flowers don’t usually show up all over the plant. Make sure to look around in different places, especially near the top of the plant and closer to the lights

Note: Pre-flowers show up most often near the top of the plant and closer to the lights but could be anywhere on the plant. There may be just one on the whole plant so you may have to search all over!

Male Pre-Flowers

Male pre-flowers tend to have a “spade” shape, like the spades from a deck of playing cards. Male cannabis plants often (but not always) reveal their sex sooner than female plants.

Male pre-flowers tend to be shaped somewhat like a spade

This male plant was only 3 weeks when it made its first pre-flower. Notice how tiny it is compared to the giant-sized thumb! Often it’s unclear what the sex is when a pre-flower is this small (unless you’ve got a lot of experience) so if you’re not sure, it’s a good idea to wait and see how it develops, just in case.

Just to give you an idea how small these can be when they show up…

This is the exact same picture as above, but with the pre-flower made bigger so you can see it. Pretty tiny, isn’t it?

Male pre-flowers are basically immature pollen sacs. When the plant starts flowering, they will grow and turn into bunches that almost look like grapes.

I’ve also noticed that sometimes (though not always!) the stipules on male plants seem more “leafy” and less “pointy” than stipules on female plants (the stipules are the green hair-like growths near where pre-flowers show up). However, this is just a generality, and should be used together with other factors to determine if a plant is male! There are definitely male plants with pointy stipules and vice versa, but it’s sort of a general difference.

This particular pre-flower is really tough to determine. However, in the end, it was a male plant. The little “stem” is one clue it may be male

Just like the above male plant, sometimes you get almost what looks like two tiny little leaves that the pre-flower pollen sac “unfurls” from. In the above picture the pollen sac is still mostly hidden, while in this next picture, the tiny growths have opened up to fully reveal the pollen sac. This can be confusing because these extra growths don’t appear on all plants, and are not a pre-flower or a stipule.

Here’s another male pollen sac pre-flower that’s on a little “stem”

A single male pre-flower appears

Once you see multiple pollen sacs and no white pistils, you can be confident it’s a male plant

Although this plant ended up being male, the stipules are long, pointy and crossed as you’d normally see with a female plant. That’s why you need to confirm sex with the pre-flowers and not just look at other factors on the plant!

Sometimes the pollen sacs look a little unusual when they first start growing in, but you know it’s male when you see several pre-flowers without any pistils stacked on top of each other like bunches of grapes

If you click the following picture and zoom in close, you can see pollen sacs scattered among the leaves

This is what male pollen sacs look like when the plant actually starts flowering

This male cannabis plant has gotten further along in the flowering stage

This is what a male plant looks like at maturity when it’s starting to spill its pollen

Another example of pollen spilling onto a nearby leaf

For those who’ve never seen a male cannabis plant in its full glory 🙂

Ok, now that you know what male pre-flowers look like, what do female pre-flowers look like?

Female Pre-Flowers

Female pre-flowers tend to be longer and narrower than male pre-flowers, sometimes with a fat bottom. They also usually (but not always) have 1-2 white hairs (pistils) sticking out from the top. Sometimes it takes a few extra days for the pistils to appear.

Wispy white pistils are a sure sign that you’re looking at female pre-flowers

This pre-flower doesn’t have a pistil sticking out at first, but the shape helps tell you it’s a female plant. If you’re not sure about sex after spotting a pre-flower, it’s a good idea to wait and see for a little while, just to see if a white hair appears (which means it’s definitely a girl)

Another example of female cannabis pre-flowers that haven’t revealed their pistil yet

Here’s a picture that shows a pistil right as it’s emerging from the calyx!

If the pre-flower is very pointy and thin like this one on the right, it is often a female pre-flower

Some of the time the stipules (green hair-like growths near where pre-flowers show up) will cross each other on female plants. This certainly doesn’t always happen, as you can see from the pics of female pre-flowers on this page, but while girls can go either way, male plants rarely have stipules that cross each other. So although crossed stipules cannot be used definitively as a way to identify female plants, it can be a small clue to help guide you when you’re not sure. For example, the following female pre-flower doesn’t have a pistil, but the long thin shape combined with the crossed stipules help indicate that this plant is a girl. Whenever in doubt, wait a week and look again!

This female plant has a long, thin calyx and crossed stipules, which are typical female plant features

In this pic, you can see white pistils emerging from the calyxes. Female pistils are white and wispy, never green.

Here’s another female pre-flower that doesn’t have a white hair yet, but you can tell it’s female because it’s long and narrow, instead of spade-shaped

One last female pre-flower without a pistil yet. The long narrow shape is the only thing that gives the sex away until pistils begin to emerge

Super close-up picture of a female cannabis pre-flower

Female cannabis calyxes with pistils, under an LED grow light

Did you know that pre-flowers/calyxes/flowers are actually what holds seeds if your plant gets pollinated? Once pollen touches the white pistils, the pollen gets delivered to the inside and a seed starts forming!

Variability of Cannabis Plant Sex – How to Increase Ratio of Female Plants with Regular Seeds

In fact, to this day scientists are still not sure exactly what causes certain plants to be one sex or another after sprouting. We’ve identified several factors that predict the overall likelihood of male/female plants (for example feminized seeds always produce female plants no matter what), but sex seems to be somewhat fluid in cannabis plants when they’re first germinated.

Certain conditions such as excessive heat, stress, unusual light periods and nutrient problems can cause a greater percentage of plants to produce male flowers.

You may be able to increase the percentage of female plants with regular seeds during the first few weeks of life

On the flip side, the following factors may possibly increase the ratio of female plants with regular seeds (learn more):

  • Healthy Mom – Only grow seeds from a vigorous, healthy mother plant who never showed any signs of herming or male pollen sacs (seeds are more likely to grow pollen sacs if the mom plant had a tough start in life, or hermed during the flowering stage)
  • Cool Temperatures – Give seedlings slightly cool temperatures (65-75°F day and night) and avoid excessive heat
  • High Humidity (50-70% RH)
  • Short but not too short days. Keep consistent day and night periods with no light interruptions at night, and days should be 14-18 hours long (between 14/10 and 18/6) for the first few weeks
  • Blue light. Always start seeds under a vegetative grow light (something with plenty of blue like a Metal Halide or a 6500k CFL/T5/fluorescent)
  • Avoid Deficiencies – Make sure to provide plenty of Nitrogen and don’t let seedlings become nutrient-starved or run into other types of deficiencies
  • Prevent Stress, especially heat or light stress during the first few weeks
  • Happy Roots – Avoid over (and especially) under watering

Once a cannabis plant is about 3 weeks old, its sex is pretty much completely set and can be determined either by visual inspection or by chemical leaf test.

Unfortunately, due to the fact that different environmental conditions during the first part of life can alter the sex, you can’t look at seeds and definitively know one way or the other whether the plant will end up being female because even the plant doesn’t necessarily “know”.

For example, say you take a clone of a seedling before it’s 3 weeks old. It’s possible that one clone will be male, and the other clone will be female. However, if you take a clone after week 3, the sexes of clones will always match each other. This is further evidence to indicate that the environment can affect sex expression in some cases.

Learn how to find tiny pre-flowers at the base of each leaf to determine the sex of your plant in the vegetative stage (at only 3-6 weeks from germination)!