26th May 2013 42 Comments »
Peoples interest about autoflowering cannabis plants and how to grow them have been exploding in the recent years and will continue to grow more and more as new and even more autoflower plants reach the seed market. The Google trends shows us that in the last year alone autoflower searches have been exploding and people want to know more about these magnificent plants.
I have been creating articles about auto flower growing for the past two years and now I want to post a complete autoflower grow guide with a bit of information about each subject with a link to the more detailed article.
Why grow autoflowers
First of all you should know why to choose autoflowers over the photoperiod plants?
There is a complete answer on the homepage, but in short autoflowers are small, stealthy, they grow fast, produce big yields, have amazing mold, pest and insect resistance and as an added bonus can flower under any light cycle. These all are amazing possibilities every grower should see and think about but the main autoflower growers are the newcomers as these plants are really easy to grow!
Apart from the short strains there are also bigger, heavier strains that are almost as big as regular ones but will still flower automatically and these are the SUPER autoflowering plants.
SUPER autoflower strains
These SUPER strains as I mentioned before are amazing as they are basically a regular Indica or Sativa strains with the added benefit of the autoflowering gene and the added mold/pest resistance. These strains were created with countless breeding cycles to get rid of the dwarf traits and get a truly high yielding autoflower plant.
You can read more about these SUPER autoflowers HERE
Regular cannabis plants autoflowers are two gender plants and any regular seed will get 50:50 chance of being male or female. This ratio is good for seed creators and autoflower breeders but not good for the regular growers as we need just the females. The feminized seeds will give you about 99 % female ratio and that means no more male removals or unchecked males pollinating the garden. Autoflowers are in no way worse than the regular cannabis when it comes to hermaphrodites but sometime they will come and you generally want to stay away from them unless you want to create female seeds as a female plant that shows some male pollen sacs is the way to create feminized seeds.
Indoor autoflower grow vs outdoor autoflower grow
Autoflowers can be grown indoors and outdoors and both places have their advantages, but it basically is up to you to decide the best growing environment. Here are some advantages to indoor and outdoor growing:
Autoflowers can be grown stealthy in mini cabinets,
You don’t need to change light cycle,
You can grow them in the vegging room where regular photo-sensitive plants are growing,
You can get a harvest every two months from seed.
You can get multiple harvests in one season,
Autoflowers are adapted to resist pests and mold,
They stay small and won’t be noticed by unwanted eyes,
They can grow in any time of the year if the temperature is not below 10 to 15 degrees Celsius.
How to choose seeds
Before growing these autoflowering cannabis plants you need to get some seeds because these plants are pointless to clone as I explained here.
So when you want to start growing an autoflower plant you will have a broad choice of seeds and strains. The big choice can overwhelm you, but basically you need to think about your growing conditions and space as well as the THC to CBD ratios and the smell and taste you want.
You also need to think whether you want Feminized seeds or Regular ones as the Feminized seeds are Pricier but they will give you all females whereas the Regular Ones will give you a 50:50 chance of Males and Females.
If you have a small grow room then you need to get the smaller Indica autoflowers but if you want a taller one for outdoor or indoor grow operation then the Sativa dominant autoflowers will be good for you.
Regular autoflowering seeds are good for breeding purposes but the feminized ones will give you 100% female ratio and you won’t need to waste soil or growing containers/space to grow plants and then get rid of the males.
You can grow autoflowers in soil, soilless mix or hydroponically but for the purpose of this guide I will just give a small introduction on soil growing.
Basically there are two types of growing mediums: With and Without nutrients. The ones with nutrients can usually nurture your plant for the first weeks of its growth but the soil/soilless mix with no nutrients will need all the nutrients to be supplied artificially with fertilizers. The mix with nutrients usually has slow release of these nutrients so they are available slowly and won’t damage your plant but the soilless mix has a neutral PH and no nutrients!
If you want to learn more about autoflower growing in soil then visit this page.
Like any other plant watering cannabis is necessary because water is the lifeblood of the plant and all the nutrients dissolve in water so the plant can absorb them. Remaining water is evaporated through the leafs in the photosynthesis process.
Each growth stage of the plants life requires a different approach to watering. In the vegetative and flowering phases you need to supply a lot of water as these plants will use up quite a bit of this stuff. In the germination and seedling phase you need to add a little bit of water with a hand myster or pour it directly around the plant. A cup of water should be enough and for the first days even a cup will be too much. As for the timing, you need to check the soil humidity with a soil humidity meter or by just checking it with fingers. If it is dry then it is time to water. In the vegetative and flowering stages you will typically need to water once every two days but it all depends on the temperature and pot size.
A good way to know how much and when to water is this: if the pot feels light then water it until there is a little runoff water at the bottom of the pot, then let your plant grow and use it up till your pot feels light again.
Over Watering and under watering can do some damage for your plants and in extreme cases you can irreversibly damage your crop. Signs of under watering is wilting and weak stems but overwatering can express itself as a yellowing of leaf tips and it is the most common autoflower growers mistake.
Cannabis plants need nutrients to grow and produce leaves, stems, buds and even seeds, and without nutrients your autoflowering plants will die but with too little nutrients it will struggle to grow and will be pale, with small leaves and almost no yield. From the other side too much nutrients will stress your plant by producing nutrient burn and a severe case of this nutrient overdose can also cause plants deth.
Basically cannabis plants need 3 main nutrients – Nitrogen(N), Phosphorus(P) and Potassium(K). There are also some secondary nutrients and trace elements but almost all of the pre-mixed soils and fertilizers have those needed elements. If you are using soilless mix then you will need to supply your plants with nutrients using fertilizers, because they always have the secondary and trace elements. The main elements are expressed in the N-P-K ratio (for example 10-10-10) and the numbers presented mean how much percentage of that solution is each main element. In the 10-10-10 example you would have a 10 % nitrogen, 10 % Phosphorus and 10 % Potassium and it would be an all around growing mix.
If you want to know everything about nutrients you can go to my most popular post about autoflower nutrients.
If we are talking about the growing mediums and fertilizers I need to mention the PH scale and that autoflowers like a PH of 6.2 to 6.5 but some slight variations won’t affect your plants that much. If you don’t know what the PH scale is then you can read a detailed article on autoflower PH here!
Grow room design
When growing autoflowers indoors you need to also think about the Grow room design, ventilation, lights, humidity, temperature and other factors that could affect your plants growth.
First of all there is the space where your intended grow room will be and this can be anything from a PC case or a cabinet to a large scale room or office. In this guide I will only be talking about smaller grow rooms as usually large scale growers know what to do.
So when you choose your grow space you should think about how much light you will have and how much plants you will be growing. If you choose smaller autoflowers that will only get 40 to 50 cm in height then you should be golden even with a small cabinet on top of your closet or any other place where you can safely install lights and ventilation equipment. Another cool way to grow your autos are the Space-buckets that are a home-made growing domes made from plastic buckets.
After you have chosen your grow room location you should first think about the Light you will be using. There are multiple choices for you that can be a bit confusing at first, but when you understand the principles then it is quite easy to select the best grow light.
There are LED lights, compact fluorescents, T5 , High pressure Sodium and Metal Halide lamps which all are able to grow cannabis from seed to harvest. When choosing a light you need to know that different lamps give off different light spectrum and Intensity as well as more or less heat!
All plants will soak up light though small molecules in their leaves called photo-pigments. These photopigments are of different shape and stature so each one can take in different kind of light spectrum (light wave length). Different light sources produce different wavelength light and you need to know which light to purchase in what time of cannabis life. In the nature plants have adapted to the natural sun light cycle so they soak up all the visible light spectrum, but there are two stages of plants life and two different light uses. Cannabis plants love light that is mainly in the Red or Blue spectrum and that means the 650 and 475 nanometer spectrum. In the early stages of plants life they need more of the blue light so you need to supply a bigger color temperature light and the best are somewhere around the 6500K scale. But as the weed plant starts to flower it will soak up more of the red light that is in the other end of the light line and usually is found in the 2700K lamps.
High pressure sodium lamps are the golden standard in cannabis growing community but not so much in the autoflower world as mainly small scale growers are growing autoflowers. HPS lights are usually made for big operations because they produce vast amount of heat but they are also the most efficient as well, if we compare the lumen to watt ratios. HPS light are best for the flowering stages of autoflower plant as they give off intense light that is high in the RED spectrum so that the right photopigments can soak in more of the red light. HPS lights are usually large and they chew vast amounts of electricity but with them you will be able to grow amazing buds.
Metal Halide lamps are the second choice of regular weed growers but they are regularly intermixed with HPS grow lights because these bulbs give off more of the BLUE spectrum of light that plants need in the vegetative growth. You will be able to grow a complete crop with MH lights but you will do best if you change to a HPS light when the plant starts flowering. For this reason Metal Halide lamps are usually used for seedling and vegetative growth of the plant and then growers change over to the HPS or different light source. MH light as well as HPS will give off vast amounts of heat so they are not good for small scale growers. But they are very efficient and will grow dense buds.
Compact fluorescent light are more well known for lighting up our homes not growing weed but you can most definitely grow cannabis with them. Compact fluorescent lights are not as efficient as HPS, MH or LED lights but they are good enough and for small spaces they are amazing because they give off small amounts of heat and you can spread them out around the plant to get an optimum light spread to all leaves and buds. CFL bulbs are also the cheapest ones to buy because you can simply go to your local DEPOT store, pick them up and start growing your own plants. There are also different kind of Color temperatures of the CFL lights but the most common bulbs are the 2700 K and 6500 K lights so use the 2700 for flowering and 6500 for vegetative growth, but it is best to supply both bulb types for the entire plants life so mix them up and your autoflower will be happy!
T5 lights are the long fluorescent tubes you can see in offices and warehouses, but they are actually very good grow lights! They can be great grow lights because they spread the light evenly, they don’t get so hot and they are more efficient than the regular CFL bulbs. They have the two distinct color Spectrum configurations as well and you should mix them up for the optimum growth.
LED lights are the new trend in the autoflower community as they produce low amounts of heat and each led light will produce a specific color temperature light so they can be customly chosen for optimum growth rates. LED lights are not more efficient than High Intensity discharge lamps but they are close! Comparing LED lights to other light sources they are perfect because they can produce specific light frequency that allows growers to pick specific LED lamps to meet their needs. That allows plants to better absorb the light as only the light that they absorb is made so the total efficiency for cannabis growth is higher than any other lamp. LED light have a very long life span and some manufacturers say their bulbs are rated for 50,000 hours but in the real life you will get a much greater life span with small intensity or efficiency losses.
You can read more about each specific light at the light section of this website.
After you have set up a light source, you need to think about the ventilation and buy some vent fans that will blow air inside your grow box as well as outside it and even circulate the air inside the room. A good rule of thumb is to purchase a fan that is able to get all of the air out of the grow room in about one minute. All ventilation fans have a rating of CFM that stands for cubic feet per minute and if you measure your grow room and calculate what is the total volume then the fan need to be able to move all of the containing air out in about one minute. There are different kind of fans but basically they are different in just three things: size, sound and the amount of air they can move.
For small grow room you may need only two exhaust fans but for larger operations with more plants you will definitely need more as the air inside the grow room needs to circulate because plants will take up all the CO2 of the surrounding space fast. If the grow room is small then the fan that blows air inside it can supply this air circulation but for larger grow rooms you will need an oscillating fan that will mix the air and your auto plants will love the fresh air and will grow faster and the little stress that the plants will endure from the airflow will also make them more resilient and with stronger stems.
For the intake and exhaust fans you need to position them accordingly as the hot air rises inside the grow room. The exhaust fans need to be able to ventilate the hot air outside at the top but the cold air needs to be supplied at the bottom!
When you are thinking about the ventilation you also need to think about light leaks and odor control as cannabis is a strong smelling plant and if the smell is not absorbed by some material it will be present in the surrounding area around the grow box / room. The only thing you can do to get rid of the pungent smell is to introduce a carbon filter to the exhaust fan. This filter will take the odor out of the exhaust air and you or anybody else won’t be able to smell your marijuana plant growing. Carbon filters are in different sizes and shapes and you can even make your own from activated charcoal but the best filters are the ones that can be bought at the grow shops. They are made exactly for the odor control and usually are pre-made to go together with a specific exhaust fan. These filters will subtract some of the fan power so it won’t be able to exhaust as much air from your grow room so it is best to get 30 to 40 % bigger CFM than you need.
After you have supplied your grow room with light and ventilation you need to think about how your light is reflected from the sides of your grow room. If you are using a pre-made grow box you will have a reflective material pre-installed that will reflect almost all light back to the plants. That will increase their growth and in essence increase the lamp effectiveness. But if you are creating your own grow room then you need to install a reflective material on your own. Many growers use the plastic gardening film that is white on one side and black on the other as the white side is about 50 to 70 % reflective and will increase the intensity of the light inside your growing room. This plastic is cheap but not every grow room is the same and a white paint will also reflect some of the light. If the paint is glossy it will be more reflective. But The best solution for you is to get a mylar sheet that is specially made for grow rooms. It will reflect 99 % of the light and it is completely light proof, no light photons will be able to get out of your grow room. There are also growers who use the ordinary mylar foil or even the thin foil but the thing with foils is that they are not 100% light proof so they are not 100% reflective and they tend to crumble up so there can be some hot spots where more light is reflected and the plant can get burned at that spot.
Auto Flowering cannabis plants grow best in certain humidity levels and any changes could decrease the yield or introduce some mold and pest problems. Basically at the early stages you need to supply around 70 % humidity so your seedlings can develop healthy. Later when the flowering phase starts and your plants are starting to show white hairs you need to lower the humidity to about 40 % but some variations will not greatly affect your plants. Basically too high humidity will increase the chances of fungus and mold penetrating your garden and the plants will also not be able to grow to their full potential and respire water in the air so easily and theyre development will be stunned.
Too low humidity from the other hand will stress the plant by not allowing the stomata (cells that are responsible for water respiration process and gas exchange) to open and close properly so the plant will again struggle to bread.
The humidity is measured by a hygrometer and it ranges from 0 to 100 % and that means that it is the actual percentage from the total amount that the air can hold in this temperature. As the temperature increases the humidity drops as air can hold more moisture and the reverse is true when the temperature drops. Temperature control can be good for humidity but the best way to increase humidity is introduce water in the form of vapor or liquid. If you insert an open top container in your grow room which holds water then that water will slowly evaporate and the humidity will increase, but if you want drastic changes spread some water in your grow room with hand myster or buy a device that is made directly for this purpose – electric humidifier. But if you want to get your humidity levels down you need to pour some salt in a container and set it inside your grow room. The salt will slowly absorb the water vapor and your humidity percentage will drop. There are also special dehumidifiers but they can be expensive to buy.
You can read more detailed article about humidity here!
Temperature is another crucial part of cannabis life cycle as these small plants have adapted to grow in specific conditions that are present in the environment. Automatic plants grow best in temperatures that range from 24 C to 30 C but some variations to both sides won’t affect them as much. Autoflowers by their definition are tough and in the spring and autumn the temperatures can get pretty cold so these plants have an increased temperature resistance and they can grow in almost any conditions where the temperature doesn’t get below the 10 C mark. If it does, then they start to greatly diminish yields and even die. Inside growers will most likely be faced with too hot temperatures and they will need to instal more powerful fans for the hot air to be exhausted fast.
Basically the temperatures can be lowered by increasing the exhaust fan power or by changing the light source from HID to CFL or in the best case to the LED one. There are also solutions where growers introduce glass directly below the bulbs and seal that part off and install different exhaust systems for both parts of the grow room, but in this case they are losing some light power and you will need to evaluate, how the grow room is coping with temperature,before knowing your best solution.
Basically autoflower plants will grow under any light cycle but because cannabis is a C3 plant it gathers energy only in the light period and so the best light cycle is where the plant is able to get the largest amount of energy. That means that for the best case scenario you should let the lights shine 24/0 light cycle. Autoflowers will also grow with a dark period and if you want to save electricity then you can grow them under 18/6 or 20/4 light schedule, but those plants won’t be as big and they won’t have as much weight. These plants will also grow under 12/12 light cycle but that will diminish the yield. But you can easily stick them in the vegetative or budding room and get fast, amazing buds!
For more information about the autoflower light cycle visit this post !
Pot size is another important part of the whole grow operation as too small pots will hugely decrease the harvest but too large pots will be hard to manoeuvre and you will waste a lot of growing medium. Basically weed plants need a gallon of growing medium for every month they stay alive so for autoflowers you need somewhere from 1.5 to 3 gallon growing containers (6 to 10 liters). For the small plants, that can be ready in less than two months, there is no need to pot them in 10 liter pots because they won’t grow that long to utilitate all that soil and expand their roots throughout the pot. But from the other hand those large SUPER autoflowers will need at least 10 gallon pots, because they can get huge and grow for 3 to 4 months and they will definitely utilize the whole pot! Pot size can also be a good way to manage your cannabis plants size as those plants grown in smaller pots will stay smaller and for small grow rooms that can be a great benefit.
More on the pot sizes in this article!
Training techniques are used to lower the plants profile and to get more light on all the lower branches to create an even canopy. Training techniques have been effectively used to increase yields and maximize the grow space or lower the amount of plants necessary for the same yield. Basically there are two types of techniques and they are Low stress training and High stress training where in the high stress training a plant is hurt in one way or another but in the low stress they are just slightly bent. Autoflowers are time sensitive plants and they don’t use the light cycle as an indicator for their flowering stage so they cannot be vegged as long as growers want. This is why you can’t High stress train autoflowers as from these incidents the plant may need a day or two to recover and if it lives only for 80 days then 4 days would be 5% of its growth and the yield loss will be even more significant. Autoflower growers usually use the Low stress training methods like Tie down or SCROG (Screen of Green) where they bend the main branch downwards to get more light and the vital fluids to the lower ones to increase their growth rates. This happens because cannabis is a plant that advances the main cola to the sun the most and it does this with the help of auxins that flow through the plant but are in the greatest quantities at the top! When the plants main shoot is bend down the surrounding ones increase growth and soon they will surpass the main shoot and again can be trained down. This process will give you an even canopy and you will be able to get more grams from the same light and you will be utilizing all of your grow space.
To Read more about the Low stress training methods go here!
Seed germination & planting
Autoflowers life starts with a seed and that means you need to properly germinate them to get a great germination rate and not to waste any money on seeds that just doesn’t germinate. Cannabis seeds can be germinated in two distinct ways: Natural in the soil or without a growing medium in a container. Both of these methods work well but each one has its own advantages. For example in soil you let the seed germinate as it would in the nature so it is the least stressful way but the seeds that doesn’t germinate will take up pots and will waste your grow space. But seed germination without growing medium is more controlled and you can control all the aspects and affect them as you like so you could potentially get more results. This second method is most widely used by autoflower growers and it just means that you put a seed inside a wet paper towel or toilet paper and seal in some kind of a container that will hold the humidity. These seeds will sprout in a matter of few days and then you will need to transplant them in their final growing medium. But the organic method is even easier as you just need to dig a hole twice as deep as the seeds length in a wet growing medium and let it germinate like the nature is intended to.
There is one stage of seed germination that is different and that is the pre-soaking process. This process usually is done with older seeds and some growers say that it increases the germination rate. To do this you need to take a glass of water and dip the seeds inside. At first they will float on the top but after few hours they will sink and start sprouting. You can take them out at the moment when they sink or when they are sprouted but don’t let them soak for too long as they can die.
You can find out more about autoflower seed germination here!
When I mentioned the seed germination I said that you need to put your seed straight into the final growing medium and this is because you don’t really want to transplant autoflowers. These small plants are not made for transplanting as again any stress will lower the yield and transplanting shock can be from few hours to a couple of days and that again is time your plant could have grown and produced leaves/ stems/ buds.
But if you must transplant them you need to do it really carefully and put them inside the same growing medium which is pre-soaked with PH neutral water. If you have a dark period inside your grow room you need to do the transplanting exactly before the night time and let the plant rest, but if you run your light 24/7 then do it at the evening as in the night the temperature will lower a bit in the grow room even if the light are on and that will allow your plants to cool off and regroup for the full growth again.
When the seed is sprouted and the first leaves appear out of the ground, the seedling growth stage starts. At this stage the plant is creating massive root growth and it puts all its energy inside the expansion of the roots so the leaf growth is slow. This phase is crucial, but your plant needs no added fertilizer at this stage as any stress in this phase can kill the plant. You need to be careful not to do anything wrong. Humidity needs to be increased and those little plants need warm conditions but the seedling phase is short and it ends when the first true leaves appear.
Pre-Flowering growth phase
In the pre flowering phase the plant is undergoing the vegetative growth stage where a massive leaf and stem explosion will happen. In this stage the plant will grow really fast and it will need added nutrients that will allow all those new leaves and stems to properly grow. In this growth stage you need to start introducing fertilizer, but do it mildly applying ⅛ or ¼ of the recommended dose and slowly building it up to 1.2 the dose. The fertilizer needs to be rich in Nitrogen as this element is responsible for all the green growth and fluid transition in the plant. In this stage also the humidity needs to be lowered to 40 – 50 %. Small stress in the vegetative growth phase would not result in a plant’s death but it will result in diminished yield so as always be patient and care for your plants.
Flowering growth phase
The real miracles start happening when that plant goes into flowering phase which can happen anywhere from 2 to 4 weeks and at this point plants will start to show the first signs of flowering – preflowers. At this stage growers usually identificate males and remove them to get the sensimilia (seedless) garden. At this growth stage you need to supply your now flowering ganja plants with a humidity below 50 % and the ideal is from 35 to 45 %. Your plants will also need different nutrients than in the vegetative growth stage and they need more Phosphorus and Potassium that will increase the bud growth rates and will allow them to swell and swell. Usually budding fertilizers are lower in the Nitrogen and high in Phosphorus and Potassium but the secondary nutrients contents are the same. From the first day of the preflowers it can be from one to two months till the harvest so a lot of things can go wrong but in general at these growth phases you’re less likely to damage the plant as it just need proper fertilizer and room temperature/ humidity to grow. As this stage comes to an end the flowers start to really swell up and the hairs start to turn brown. The trichomes that are on the plants where the active ingredients are will start to turn amber and slowly die.
Harvesting your ganja plant is the best thing in the world as all the great work you put into it is at last over and you can chop off those buds. This is true but many growers doesn’t realize that this is the most crucial stage of your growth as too early or too late harvest will ruin the active ingredients of the cannabis plant so it won’t be of any use. The best time to harvest an autoflower depends on the strain but in general you need to check the trichomes and when half of them are amber then it is time to harvest that plant! Some sativa-dominant strains won’t amber up their trichomes and you can harvest them when about 10 to 20 % of them are amber, but indica dominant ones will do this degradation process fast so your harvest window is short.
You need to cut off the water for the last day or two to get more dried up plants but before that you need to flush the plants to get rid of the excess nutrients in them.
The harvesting process is quite simple and you just need to cut off the plant from the steam and cut the buds off the smaller stalks. But before doing this you will need to get rid of all the big leafs and manicure the smaller “sugar” leafs as usually growers make hash, oil or edibles from them and use only the most trichome rich parts of the plant for immediate consumption. When the manequering process is done you need to start drying your harvest. The drying process needs to happen gradually in the course of two to three weeks and too fast drying will ruin the taste of tour weed. In this process your buds will lose from 60 to 80% of their mass and you can get the time when they are ready by weighting them with precise weight scales or by trying to bend one of the streams. If it bends they are not ready, but if it snaps they are ready for curing.
The curing process is the final process in your growing and it is done to get the best taste from your plants. In the curing process the buds are sealed inside an airtight container that lets the moisture come out from the middle of the bud and evenly spread throughout it. This air tight container needs to be opened few times a day for the first couple of days and then gradually the open rate will need to decrease to where the buds will be completely ready for usage. This process can happen from two weeks to several month depending on the strain and bud density as well as amount but it typically is done in a couple of weeks.
Storing cured buds
When your harvested buds are cured properly there is a little bit of moisture left in them that will give you the great burn but won’t ruin the bud if left inside a sealed container. You can store weed for as long as you want but it is best to use it in the first couple of months to a year because by this time buds will have evaporated all moisture and will not burn so good and will not taste as good also. With time the active ingredient count decreases as they slowly decompose in different kind of molecules. This storage process is usually done in an air sealed plastic bag or a glass jar and once every two to three weeks the container is opened for more of the excess moisture to evaporate and after couple of month those buds can stay inside the container for years without any oversight. These completely sealed storage containers need to be held in dark cold places like in the freezer or basement, and will stay viable for years but most often than not you won’t store them as long!
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