Early sexing and learning sexing of marijuana
BY NOW YOU'VE MANAGED TO SET UP THE BASIC
growing environment and experimented with modifying and controlling it to promote better, stronger plant growth. You will have observed your plants forming a number of nodes and a small leaf mass at the top, which you know is going to form the next set of leaves and branches. Your leaves should be flat and stretched out to receive as much light as possible across their surface area. If they are, then your plant is enjoying its environment. If not then maybe you should consider turning to the Problem Solver.
You should also note that almost everyone makes mistakes the first time growing. Very few first-time growers get to this stage without experiencing at least one problem, so don't feel bad if you didn't get it right the first time.The trick to growing healthier, more potent plants is to keep growing (and reading this book).
During the vegetative growth stage your plants will begin to grow quickly and produce more leaves and new branches. The stem will also grow thicker. This is the point when your plants begin to really look like marijuana.
Then, one day you will notice that your plants appear to be doing more than just growing vertically and producing leaves. You take a closer look and there appears to be new leaf growth at most of the node regions between the stem and the branches. Your plant is now developed enough to receive more light energy and covert this energy into more side branch growth. These new growths produce more leaves, branches, and eventually flowers. This type of new growth at the stem's node regions is called lateral branching or secondary branching. This is really where the extra node regions begin to take shape.
After a few more weeks of this secondary growth your plant is looking more bushy and certainly has more node regions. It is during this time that your plant has reached sexual maturity and is ready to show sex. How long this takes depends on the strain you are growing but after the seedling stage has finished you are looking at a time period of 4 to 8 weeks vegetative growth. With Sativa strains this can take much longer.
At a certain stage towards the end of vegetative growth the plant enters its pre-flowering phase and, as a grower, you need to tailor your grow space and gardening approach to this new stage in your plants' life cycle.The next section explains how to identify the pre-flowering stage.
PRE-FLOWERING AND EARLY SEXING
Recall that during pre-flowering, plants start to exhibit their sex. As a grower, you should be hoping for as many females as possible. Pre-flowering occurs at the node regions. Towards the end of vegetative growth you need to check your plant nodes for what is called calyx development. A clone will carry the exact same genetic makeup as the plant it came from, so if you know your clone's history you will already be able to predict it's sex.
CHECKING FOR CALYX DEVELOPMENT
Choose a plant. First of all examine the node regions of the plant where the branches meet the stem. You are looking for very small pod shaped organs here at these regions.* If you don't find any here then move outwards along each branch checking each node region until you come to the tip. If you do not find calyx development then your plant has not reached its pre-flowering phase yet. You need to wait for it. Calyx development will come in time.
There are three early indicators of plant sex, but they are not 100 percent accurate.So remember, these methods can fail, but are often accurate predictors of your plants' sex.
First Early Sexing Method
If you've been growing the same strain and all the seeds were started at the same time, then you may notice that some plants are taller than others: the smaller plants tend to be female and the taller ones tend to be male. You can separate these plants into two sections in order to see how good your guesswork was when you do definitively identify sex. The other thing to note is that male plants generally 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 an early date is to examine the calyx* with the aid of a very fine magnifying glass. If the calyx is raised on a small, short stem then it's probably a male. If the calyx isn't raised on a small short stem then it's probably a female.
Third Early Sexing Method
'Force-flowering' is probably the best early-sexing method. To force-flower a cannabis plant, simply take a cutting and place it in a cup of water or a cloning medium, such as rockwool. Expose the cutting to 12 hours of light followed by 12 hours of total darkness. The cutting should flower and display its sex — however the plant must be mature enough to present its sex. An immature plant will not show sex because initial calyx development is not photoperiod-related. Plants normally mature around the forth week of vegetative growth because sex is not genetically determined until the third week of growth.This also applies to 'feminized seeds,' which can, and often do, turn out to be male.** If your plants are exhibiting calyx development, then this is a suitable method of determining the plant's sex.
These methods are NOT 100 percent accurate. Later in this Chapter we will explain how to definitively identify the sex of your marijuana plant.
WHEN TO FLOWER?
Your plant will remain in the pre-flowering stage between one and two weeks. During this period, the new growth regions begin to change shape depending on the plants' sex. 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 issues to consider before you make a decision:
• Most cannabis plants can be kept alive for up to 12 years by simply keeping a light on the plant at all times. Even if the plant only receives light for a few hours a day it can still live for a long time. It all depends on how the plant is treated. These plants will grow to a certain height and then form into a bush. Eventually they will stop producing branches and will spend the rest of their lives growing new leaves to replace the old ones. By keeping the plant in vegetative growth longer, you allow it to reach its optimal size of vegetative growth and the plant will stop growing. Most growers flower before this, when they see calyx development, in order to speed up the growing process. For example: A plant that shows sex at the forth week of vegetative growth can be kept in vegetative growth for a few more weeks to allow the plant to generate more node regions (leading to more branch and leaf growth). When the plant is flowered, this extra stage of growth should help the plant to achieve optimal results however the grow time is extended by a few more weeks to obtain this.
• Bud production does not increase at the same rate as plant growth. Bud production depends on your growing environment, your strain's genetic makeup and the amount of nodes the plant has. All nodes are potential bud areas, but every strain has a genetic threshold for bud production.
• It is possible to get more bud with lots of plants that are flowered as soon as they're 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 also produces more bud turnover per year.
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, prepare to have the space for it, because in the flowering stage, some cannabis strains can more than double in height and width.
If you want your pre-flowers to flower you only have to do one thing: introduce the 12/12 light schedule.
THE ALL-IMPORTANT 12/12!
If you've never heard of 12/12, listen up. 12/12 is the key to producing high quantities of bud from cannabis plants.
Cannabis plants grow outdoors naturally between the months of April and October/November. This means that toward Sept/Nov* the plants will be flowering. During this time the days get shorter and the nights get longer. When this occurs, the plants are subjected to 12 hours of light and 12 hours of darkness.
When this 12/12 photoperiod occurs, the plant is naturally stimulated to flower. As long as 12/12 continues the flowers will grow larger and more plentiful. This is part of the cannabis plants' natural cycle. Naturally, as a grower, you want a large quantity of flowers, and you achieve this by introducing the 12/12 light cycle.
During pre-flowering you can either manually turn on your lights for 12 hours and turn off your light for 12 hours every day or you can use a timer to automate the process.Throughout the 12 hours of darkness you should keep your grow area as dark as possible. Even something as seemingly harmless as a small desk light at the other side of your room will cause your plant not to react properly to 12/12, resulting in continued vegetative growth. In fact, any light that penetrates the darkness could stop your plants from flowering properly. That means your grow room must be sealed to the point where it is completely lightproof.
If you want to learn how to do completely lightproof your space 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 lightproof. If you borrow ideas from their tried-and-true methods (basically a thick black screening around the doorframes or any open light points) then you will have a great space for flowering plants. You should be a long way towards achieving this already if you followed the advice on covering your grow room with Mylar. If you have prevented any light from leaking out, then you should also have prevented light from leaking in.
Problems with 12/12
If you switch to 12/12 before pre-flowers have shown, you may encounter the following problems:
1. Stress-related sex problems (hermaphrodites)
2. Abnormal bud growth
Stress-related Sex Problems (Hermaphrodites)
Stress-related sex problems might produce hermaphrodite plants. The stress of what's sometimes called early flowering triggers the plant into a situation where it thinks its chances of reproduction are slim to none. That situation induces a condition or act of self-pollination, in which the plant produces both male and female flowers on the same plant. The male flowers then pollinate the female flowers, which eventually produce seeds.
The reason for this is that the plant notices that the photoperiod is irregular* and should no longer be in the vegetative growth stage but in flowering. This shocks the plant into a last ditch effort to receive pollen because it feels that it's missed its chance to receive pollen already. In the wild, males release their pollen just around the time that females begin to flower.
This is what hermaphrodites look like. Notice that bolh male pollen pods and female pistils are present on the plant. Picture by Rasta Linus.
Hermies cause problems because they may carry the hermaphrodite trait with their offspring. Genetically the hermie condition is near impossible to reverse once started. Sometimes even plants from the hermaphrodite's offspring that did not display the hermaphrodite condition can still carry the hermie trait to future offspring. If you ever see all-female seeds advertised by seed banks you have the right to know whether or not these seeds come from female plants that were stressed into producing male flowers. In general, growers try to avoid hermie plants because they spoil sinsemilla crops and breeding projects.
Abnormal Bud Growth
Abnormal bud growth is a side effect of the hermaphrodite condition. Because the
plant produces male pollen sacks with female flowers you may notice that the bud
looks different. Also, the quantity of female bud produced is decreased because of
Early-induced flowering* isn't the same thing as forcing your plants to flower. If you force flower a strain before it has pre-flowered it will flower at roughly the same time as a plant from the same strain that has been flowered after calyx development has occurred naturally. Force flowering simply acts by stressing the plant into a crisis condition.
You will get the best out of your plant by waiting until it 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'll be able to see your plant's sex.
Pre-Flowering for the 24/0 and the 18/6 photoperiods Both under the 24/0 photoperiod and the 18/6 photoperiod cannabis plants will undergo calyx development when mature enough to do so. In the case of the 18/6 photoperiod calyx development may appear more pronounced and even display its sex earlier than the 24/0 photoperiod.
It is easier to keep a plant in vegetative growth by using the 24/0 photoperiod because there are no dark periods. If you keep the plants under 18/6 the pre-flowering phase increase may cause a slow down in vegetative growth. Although pre-flowering under 18/6 does not cause flowering it certainly contributes to a decrease in vegetative activity. As soon as you go down to less than 14 hours of light the plant will normally start to flower. 12/12 is the best light regime for flowering and can be introduced as soon as calyx development appears.
THE MALE/FEMALE THING OR HOWTO SEX YOUR PLANTS
You now have nurtured your plants and watched them grow in the hope that you'l get some high-yield females in the end. If you end up without any female plant: out of all of your seeds then send the seed bank a letter explaining how 15 out o 15 seeds were male. If you're lucky and sincere in your writing, the seed bank ma; send you some free seeds or give you a discount on your next order. Seed bank: or breeders aren't responsible for male/female ratios. It simply isn't under thei control. Some people get 100 percent females while others get 100 percen males, but it is rare that such a thing will happen. To get five or more females ii a pack of 15* is a good ratio.
Males do not need a photoperiod to spread pollen. As soon as calyx development shows male flowers may appear within a few days under the 24/0,18/6 or 12/12 photoperiods. Male flowers grow more vigorously and plentiful under the 12/12 photoperiod.
A male plant will continue to flower for the remainder of its flowering period developing new calyx formations and male flowers. It can take anywhere between 12 hours and one week from calyx development for male flowers to appear and shed their pollen. It is very important to separate the males from the females as early as possible if you are growing a sinsemilla crop. In general males usually appear before females.
Pollen can easily be collected as described in Chapter 15. You can also gather falling pollen using a white sheet of paper placed in between the plant stem on the top of the pot. All fans must be turned off if you want to collect pollen this way. Fans will only blow pollen around your grow room.
Female plants can be pollinated at any time but are best pollinated between 15 and 30 days into their flowering period. Plants that are pollinated less than three weeks before harvest may result in immature seeds although plants pollinated two weeks before harvest have been known to produce seeds mature enough for germination.
If all has gone well and you've cared for your plants, they will now enter the flowering stage of the life cycle. You will remove the males and should have a number of females to work with. This is going to be the most important time you'll spend taking care of your plants.
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 to touch (don't touch them too much as they also contain the sought-after THC), and become covered in resin during the flowering period. The reason for their stickiness is that the pistils are used by the female to catch falling pollen. If the female plant isn't pollinated she'll try to grow more sticky areas. Hence the results of a sinsemilla crop ...bigger and better buds.
During the strict 12/12 cycle, a female plant will fill out more. More leaves, more branches and more flowers develop until eventually, plants reach a peak period of flowering. Your plant will start to almost take the shape of a Christmas tree. The lower fan leaves will be stretched to the maximum in order to receive the most light. Running upward in a cone shape the plant will exhibit strong floral and leaf development.
During the peak period of flowering, the female pistils on the flower's tips will swell. When the swelling occurs, the pistils will begin to change in color. They'll generally change from a white to an orange tint or from a red to a brown tint. All strains are different but in general it's a white to red or a red to brown color change. It's best to use the breeder's recommended flowering times for harvest guidelines. When your plants do this you're ready to harvest and sample your favorite herb. Each strain has its own flowering times and each strain may also have a different color tint when they reach a flowering peak.
Ignorance of all things is an evil neither terrible nor excessive, nor yet the greatest of all; but great cleverness and much learning, if they be accompanied by a bad training, are a much greater misfortune. Education is a progressive discovery of our own ignorance.