Growing Your First Autoflower – A Complete Guide

Everything autoflower

Growing Your First Autoflower – A Complete Guide

grow your first autoflower

So you’re looking to grow your first autoflower, or perhaps you’ve done only a couple of grows and want to ensure you’re doing everything correctly. In this article we will cover everything you need to grow your first successful auto.

What You Need

First, let’s look at what you need in order to grow an autoflowering cannabis plant from a hardware perspective.


  • pH meter (Either digital, or a liquid test kit)
  • pH Up and Down (Lemon Juice and bicarbonate soda can be used when growing organic, while synthetic growers can use specific pH Up and Down. Lemon juice will lower the pH of your water, while bicarb will increase it.)
  • Seeds (You will of course, require some autoflower genetics. These can be purchased from a number of local seed banks or imported. Though customs can be risky, so I’d recommend buying locally. Look for genetics that are of high quality if your budget can afford it.)
  • Nutrients (You can decide on which nutrients you want to use, depending on if you want to go organic or not. But ensure you have what is needed to cover both vegetative and flowering stages. You’ll want a nitrogen heavy feed in veg and a potassium and phosphorous heavy feed for flower.)
  • Soil (You don’t need to go out and buy soil if you’re growing outdoors, you can use your garden soil. For indoor growers, you’ll be wanting to pick up some quality soil or a coco/perlite mix, hydroponics are also an option if you’re already versed in hydro grows. My personal favourite is Freedom Farms soil.)
  • Pot (Again, not required when growing outdoors but for indoor growers, you should look at potting in a size between 10 and 15 litres for autoflowers. Some choose to grow in larger pots, but in most cases this results in wasted soil as auto roots do not occupy much room in the pot typically. If you’re growing a large yielding autoflower “Super auto” you can increase the pot size to 20L.)
  • Flexible Ties (Ideally, you can find garden ties at a local nursery, though you can also use something like a pipe cleaner. This is to act as a tie during the low-stress training you’ll want to be doing.)
  • Pest Control (Especially relevant for outdoor growers, you’re almost certainly to experience some kind of pest interaction with your grow. Whether it be aphids or spider mites. These are common pests that require control in most situations.)
  • Extras for Indoor (If you plan on growing indoors, we will assume you’ve done the research on what you will need in terms of lights, tents, extraction fans etc.)

The Germination

Germination of autoflowers are for the most part identical to that of photoperiod plants. I am personally a fan of placing seeds in a glass of water until they sink, then removing them and placing them into a wet jiffy pellet and letting it sit in a humidity dome (or humid area) for a few days, watering when the pellet are mostly dry). When germinating your seeds, you want to keep the roots fairly warm, and heating pads are an option in winter months to assist in germination. Keep your humidity dome / planted seeds in a dark area until they have emerged from the soil.

The Seedling Phase

After your auto emerges from the soil, you can place it under a light that isn’t too strong, something like a CFL or T5 is a good option for the early seedling stage. It should be able to run under these lower strength light for about a week or so, until there are a couple nodes on the plant. During the seedling phase, make sure not to over water, the most common mistake made by new growers. In fact, using a spray bottle can help in not over-saturating the medium, which can result damping off or even just slowed growth. If you are using a soil medium, you may not need to feed for the first couple weeks depending on the soil, keep an eye on your plants colour and feed when leaves show very light green or yellow colouration, which is a sign of nitrogen deficiency.

Make sure to keep your lights at the right distance to prevent excessive stretching by it being too far away, or heat issues by having it too close. Light cycles for seedlings generally use 18/6 or 20/4, the same as vegging.
When watering, regardless of which stage of life the plant is in, you will want to pH balance the water, around 5.8 to 6 for hydro and soiless mediums, or 6.2 to 6.7 for soil.

The Vegetative Stage

Once your seedling has established its second node of true leaves, it is entering the vegetative growth phase. This phase will see an increase in growth speed and the plants will begin to drink a bit more water as the roots establish themselves, though still be careful not to over water, starting with a small amount of water around the plant and increasing the radius as the plant continues to grow. Only water when the first 3 centimeters of soil is dry. In the early veg stages, you will begin to feed nutrients, starting with lower amounts and working it up, be sure not to over feed as nitrogen toxicity can affect autoflowers easily. If you see your leaves starting to get a bit too dark, lay off your feeding. Depending on your feed, you can start out with one feed a week in early veg and then see how the plant does, it’s easier to add more nutrients when signs of deficiencies slow than it is to deal with the toxicity problems.

In the middle of the vegging period, you should begin to tuck your fan leaves in to expose the lower nodes to light, allowing them to start growing up, in preparation for training. Training methods are best started around week 3, when your plant is strong enough to handle being pulled down. Depending on how vigorous your growth is, it’s possible to train at a younger age, just try aim for at least 3 main nodes before beginning LST. LST will allow the lower nodes to grow up and equal to the main cola which will result in several main colas in flower, and an increase to your yields. It is worth noting that LST isn’t mandatory and for your first grows, it may even be a wise choice to let your plant grow out naturally so you can see the typical standard growth, as LST done wrong can also lower yields. However, I will continue to discuss LST through the article for those who wish to use it.

In the latter part of your vegetative stage (this can vary as some plants can begin flowering as quickly as week 2 of veg, though around week 4 is most common), you may notice your plants are starting to really thrive. Autoflowers which begin flowering later than normal are generally “super autos”, plants bred for a longer veg cycle to create a larger plant with a larger yield. Your lower nodes should now be about equal with your main cola if you have been training it. When training, try keep all the tops at the same level to create an even canopy. Keep tucking any fan leaves that block any of the tops from the light.

During pre-flower, you will see that your plant is showing its gender and beginning the stages of the initial bud formation, this is the point at which you could choose to remove a few leaves if you want to. When it comes to defoliating an autoflower, there is a large split in opinion and some swear against it, while others say it improves their yields. I am personally of the belief that fan tucking should be the first priority, but that defoliation can also work if the plant is strong and thriving. Do not defoliate plants which are already showing signs of weakness as this will only make it harder for them. Even with healthy plants, I’d recommend a conservative defoliation process that removes 1 or 2 leaves a day.

Low stress training in the vegetative phase, showing the lower nodes growing upwards and evening out with the main cola.

The Flowering Stage

In the flowering stage, autoflowers are much like photoperiod plants with the exception that you will not be changing your light cycle. Instead of adjusting the light to 12/12, you will retain the same light cycle as your veg period, typically either 18/6 or 20/4. Both autos and photoperiods will undergo similar development and the approach one takes will be the same for the most part. Autoflowers will typically flower quite quickly, but often in the same range as fast flowering photoperiods, depending on whether the strain is more indica or sativa dominant with sativa strains take much longer generally. When the flowering phase begins, the plants will really kick into their stretching phase, during this phase which lasts for 2 to 3 weeks, you will see explosive growth that can see your plants growing up to 3 times the size they were when entering flower. It may feel like now is the right time to switch to your flowering feed, but in reality your plants are going to be using more nitrogen during this stretching phase than they will potassium and phosphorous. Because of this, you should still give them a nitrogen based nutrient for the first couple weeks, when the stretch comes to an end, you should then switch to the flowering nutrient as the plant will now put all its energy into bud formation and will not longer place the energy into vertical growth.

I tend to do some defoliation at the end of the stretch, just to ensure my bud sites have some airflow through them and make sure that the sites are all exposed to light. I also reassess my branching structures and use ties to separate any colas that may be too close and not letting enough light penetrate. The defoliation I do is minimal and again, done over a few days. For new growers, I will still recommend sticking to fan tucking until you feel comfortable in analyzing your plants health. Some strains handle the leaf removal better than others too, and sometimes you may need to try both methods before you find what works for you, it is quite personal in the end after all.

During the middle of the flowering period, you’ll see that your pistils are now starting to get swallowed by the bud formations, as they start to put on some mass. Around week 3 is also when you will start to see the first signs of visible trichomes on the sugar leaves and sometimes fan leaves too. It isn’t long after this that the smell of your plant will begin to increase too, as the trichome production increases. This is truly when you get your first signs of what to expect when you smoke the plant, as the terpene profiles contained in the trichomes will determine both the aroma and the taste of your bud.

autoflower in week 4 of flower
Apollo’s Poison autoflower in week 4 of flower, showing pistils and bud formation

You will also likely notice that your plants are now much more thirsty, and can easily go through their water within a couple of days. If you’re growing organic, it is worth adding some molasses to your watering schedule, in order to feed the microbes in your soil. Some growers may feed on every cycle, while others prefer to feed and water in rotation. Look for deficiencies or signs of toxicity during the process and add or remove nutrients as required. This can be difficult for new growers as lots of deficiencies and toxicities may look the same, but there are always other growers willing to help diagnosing your plants. Consider joining some of the grow groups on social media or local forums.

As your flowering stage continues, you will then use any bloom boosters you may have, these are typically used around week 4 to week 6. The best time for them is between the middle and late flowering stages when the buds are bulking, but before you begin to flush.

Late Flowering Stage

The length of your flowering period will vary between strains, but you can typically expect around 6 to 8 weeks of flower, with some longer flowering varieties. Because it is difficult to know the flowering period of your strain (especially as breeder specified flowering times are often not reliable), it is best to check your trichomes to know when to begin your flush.

Flushing is the process of stopping the feed, and only watering with water. Some growers prefer to do a large watering on the first day of the flush, by allowing a large amount of run-off from the pot. Other growers will just water as usual. The concept behind flushing is that your plant will be forced to use up the nutrients it has stored in itself. This ensures the smoke will be smoother. Some believe it is not required to flush with an organic grow, however most reputable organic growers will still use only water for the last 2 or so weeks of flower.

trichomes on sugar leaf
Trichomes on the sugar leaf of a plant. When checking maturity, look at the trichomes on the calyx of the bud and not on the sugar leaves.

When looking at when you should start your flush, a common recommendation is to look at your trichomes under a microscope, macro lens or jewelers loupe. When the trichomes are mostly cloudy, instead of clear, you can begin your flush. Make sure to still use pH balanced water, even during the flushing period.

Once you have started your flush, you should keep checking your trichomes every few days to see how far away from harvest your plant is.

Preparing for Harvest

So you’re wondering, “When can I harvest my autoflower?” The answer is in the trichomes. The trichomes are the small white ‘crystals’ that you see on the buds, when looked at close you will notice they aren’t actually crystals at all, and instead resemble transparent mushrooms-like extensions of the plant. These trichomes are what hold the terpenes of the plant, meaning the cannabinoids of the plant are housed within them.

Clear trichomes show a plant is not yet mature for harvest, and are not at their highest levels of THC. Predominantly cloudy trichomes tell you that your plant is maturing and THC levels are increasing. Later on you will see that the cloudy trichomes begin to turn amber, this is when THC starts converting in CBN. The increase in CBN will create more of a body high, while clearer trichomes will create more of a rushy head high. It is up to you which high you want to create. The most common harvest is at around 30% amber trichomes, this will typically give you a balanced high. When growing a heavy indica strain, perhaps for medicinal reasons like pain relief, it is also possible to let the plant mature further and harvest at a higher amber percentage. You will be sacrificing THC for CBN, but that is a trade off that many desire as they want more bodily relief. A late harvest will result in more of a couch-lock feeling.

So you’ve noticed your trichomes change colour, you flushed and now you’re ready for harvest… So what’s next?

The Harvest, Dry and Cure

Before you decide to chop your plant down, you should place her in a dark room for 48 hours without watering. This is optional, but a recommended trick that stresses the plant in the pre-harvest phase, making her think she’s about to die and thus encouraging her to put all the remaining energy she has into bud production. You don’t want to stress a plant out in the flowering stages for the same reason, she will do what she feels necessary to keep her genetics going. In flower, that means developing pollen sacks to self-pollinate, but she will also focus on ensuring her flower is at maximum potential. Doing this in the last 48 hours is safe as the plant doesn’t have the time required to turn into a hermaphrodite and instead will only have a positive impact on the trichome development.

When it comes to watering the plant, if you are in a hot climate and find that drying may occur too quickly, you can water before harvest to prolong the drying period a bit. Otherwise, in cooler conditions many growers will stop watering just before the dark period.

When drying, it is up to you whether to do a wet trim or a dry trim. If your temperatures are high, a full plant hang and dry trim (only trimming after the plant is dry) will give you a longer drying time and help preserve your terpenes better. Though some may still choose to do a wet trim (trimming the leaves before drying) out of preference, as it is easier to wet trim than dry trim. A wet trim may also make sense in winter months when temperatures are low and the drying time could be too long, an extended drying time in humid conditions will increase the chance of mold in the process. You ideally want around a 7 to 9 day drying period.

Once you’ve trimmed and dried your cannabis, you can place it in jars to cure. During the first 2 weeks of curing, open your jar and move the nugs around gently and let them breath for about 5 minutes. Do this twice a day for the first week or 2. Thereafter, burp your jars once a day. After a week of doing that, you only need to burp your jars every several days to exchange the air in the jar.

After a month (some choose to go longer), you will have bud ready to smoke. The process of growing autoflowers is not much different from regular cannabis for most of the cycle, if you’re a grower of cannabis who wants to try do some autos, I’m sure you’ll see how similar the process is. For those entering into growing through autos, you will certainly find the transition to photoperiods quite simple.

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