Topping autoflowering cannabis strains is a controversial subject for one key reason. While topping is encouraged for almost all photoperiod strains in almost all cultivation situations (unless you are running a photoperiod sea of green style grow – and even then, topping can increase yield size), the fact that autos have a very limited vegetative growth period makes topping a bit more of a challenge.
But, before we get way ahead of ourselves, lets break the whole subject down in the simplest terms possible and find out where and when to top autos, or if you even should at all…
Topping is a commonly employed HST (High Stress Training) technique for photoperiodic strains that can massively boost the budding sites on a single cannabis plant but does come with some major drawbacks for fast-growing autos.
Topping involves removing the growing tip of the main stem just above where the new branches are forming and is often combined with other cannabis training techniques. When we top a plant, it forces the main growth hormone (Auxin) to spread more evenly throughout the plant. Un-topped plants have what is referred to as Apical Dominance, meaning the main cola (budding site) will receive the highest levels of this growth hormone, which leads to uneven bud production throughout the plant.
Topping a plant removes this main budding site and causes the plant to focus much more energy on the entire growth sites, producing a bushier plant with more even bud production. When we remove the crown, the branches that are developing just below become the dominant sites, which means that instead of having one main stem, we now have two. Topping can be repeated multiple times to create a bushy plant with several main colas.
As mentioned in the intro, the reason why topping autos is controversial is that, unlike photoperiod strains, autos have a limited vegetative growth period. HST techniques like topping put a pretty hefty strain on the plant, and this stress will cause some stunting in growth. With photo strains, that’s no huge issue. You simply extend the vegetative growth stage for a few days to make up for the time lost when topping.
But with autos, that’s unfortunately not the case. On average, autoflowering plants will stay in the veg growth stage for around 2 to 4 weeks before ‘automatically’ switching over the flower production, no matter what lighting and environmental conditions they are in. While this feature is exactly the reason why autos have become so wildly popular in the last few years, it also means that you have to be very careful with all HST techniques, including topping.
What strains can be topped?
If you are going to top an autoflower, then ideally you should choose a strain that has a longer flowering period so that it has more time to recover from any stress. Choosing a sativa autoflower will give you the best chance of success when topping.
For those of you that don’t have prior experience topping, it may be best to compare autoflower and feminized seeds first and consider growing a photoperiodic strain instead. When growing a feminized photoperiod indoors you control the light cycle and therefore you have full control over when the plant enters the flowering stage. If your plant needs more time to recover or grow, you can simply extend the vegetative stage for a couple more weeks before flipping the lights to 12/12.
So, should you top your autoflower?
It’s a pretty hard question to honestly give you a comprehensive answer to. What we will say is that you should never top an auto that you haven’t already grown (probably a few of them). It’s firmly recommended that you have a thorough and extensive understanding of a specific autoflowering strain before hitting her with the hard stuff. That way you will be able to judge better how it responds and how long you have before it starts flowering.
Can you top all autoflowers?
Topping is a great technique to learn because it can really enhance the yield of an autoflower when it is done correctly. However, 3 weeks of veg growth just simply isn’t long enough for the plant to bounce back from the stress of topping to make it worth it so it is not suitable for every type of autoflowering strain. The shorter the veg period the less time your auto will have to recover. Topping tends to get the best results with taller strains with longer vegetative periods, therefore many growers use this technique with sativa dominant varieties.
Topping autoflowers: What does it do for the plant?
The aim of topping autoflowers is to increase the yield capacity of the plant. If topping reduces the vegetative growth capability of a plant, then it is unlikely to be worth it and likely to have a negative effect on yield. However, if you are growing an autoflowering strain that has a longer-than-average vegetative growth period, then topping can be beneficial and the end results will be more than worth it.
Safer alternatives to topping autoflowers
If you have been put off from topping your autoflower plants for any of the reasons mentioned in this article, don’t worry there are other less risky training methods you can try instead. Low stress training (LST) autoflowers is much less risky, particularly if you are still developing your cannabis growing skills. Techniques such as ScrOG, SOG or the tie and bend approach all cause so little stress to the plant that they can be done with any autoflowering strain and you don’t need to worry about varieties that have shorter vegetative periods.
You can also use autoflower defoliation as a way to increase yield, this method systematically removes leaves that are deemed to no longer be beneficial to plant such as drying out or yellowing leaves. You can also use this method alongside LST methods such as ScrOG, SOG and the tie and bend technique.
This is a difficult question to answer because it depends upon more than just topping or training techniques. You also need to take into consideration; nutrients, soil, pot size, climate, light quality, genetics….the list goes on.
Autoflowering strains have come a long, long way in the past decade. Once thought of as the runts of the cannabis world, autoflowers are now capable of producing some seriously impressive yields when grown correctly.
But, thanks to this explosion in autoflowering genetics, the range of strains available is almost as extensive as photoperiod strains these days. So, while one auto strain may produce multiple jars full of dank and stanky buds, others just do not yield as well.
For the sake of brevity, the highest-yielding autos usually top out at around 6 to 8 ounces per plant. That’s not to say there are no auto strains that can produce better results, but in general, you should be very pleased with this number from one single plant.
- It can increase the number of main colas, resulting in a more even canopy and bigger yields.
- It can be beneficial for autoflowering strains with longer-than-average veg growth periods.
- It can help limit the height of tall and unruly plants.
- Autoflowering strains have a limited veg period, and topping can cause stunting in growth.
- It can be detrimental if done too late or with the wrong strain.
- It can cause a decrease in yield overall due to the stress on the plant.
- It can be difficult to properly manage plants that have been topped as they will require more light and airflow.
The process of topping autoflowers is the exact same as topping photoperiod plants. With topping, you have to be extremely careful where you cut, and when you take that top shoot off.
First up, you are going to want to use the sharpest pair of scissors available. If you only have old, blunt options available then you either need to get a new pair, sharpen your old ones, or forget about topping altogether.
Next, those blades better be super clean. Remember, you are taking off the head of your precious plant, and in doing so you are opening the plant up to a range of viruses and diseases. Make sure to fully sterilize the scissors, not just the blades. Rubbing alcohol is your best friend here. Also, make sure your hands are clean, and wear a pair of surgical gloves.
The next thing to consider is timing. This is done not but by considering how many days of growth have already taken place (as this is an inexact way of assessing cannabis development), but by how many nodes have grown.
As with every other factor already discussed, this is a little controversial. Ask 10 auto growers who top their plants and you’re bound to get more than a few answers.
But, in general, we reckon that you should wait until your plant has grown 4 nodes before topping. Some cultivators may say that you can go for it after the third node has appeared, and that may work well with autos thanks to the restricted veg period.
Again, get to know the strain you are considering topping before taking off the head of any plant. Then use this understanding to make your choice on how many nodes before topping. Some longer growing strains may be able to be pushed out to the fifth node before topping, but that’s for strains that will take more than 11 weeks to finish for the most part.
As just mentioned, you only want to top autoflowering strains with longer growth periods. Now, you’ve probably noticed that almost every single auto seed company will claim that all of their cultivars have a seed-to-harvest time of between 63 to 77 days. And while that may be true of some of the options, a bunch of autos will take longer than that. Marketing is a fickle beast.
We are going to make our main point clear just one more time – ONLY TOP STRAINS THAT YOU HAVE A MORE THAN DECENT UNDERSTANDING OF.
But, if you want a few recommendations on auto strains that may work well for topping, check out the following:
Super Lemon Haze Auto
A true powerhouse of a Sativa Auto, and closely based on one of the most awarded photoperiodic strains ever to grace the lungs of weed smokers worldwide, Super Lemon Haze Auto is a great candidate for topping. She is a great yielding strain, grows tall and lanky if left to her own devices, and usually runs in the 12-week region.
Big Bud Autoflower
One of the longer-growing indica dominant auto strains currently on the market, Big Bud Auto ticks all of the boxes for cultivators looking for an autoflowering hybrid that can be topped successfully. With strong potency, huge yield capabilities, and one of the smoothest smokes available, you should definitely give her a good hard look at.
Tangerine Dream Auto
And for our last recommendation, we cannot go past Tangerine Dream Auto. With a pretty even hybrid split, huge resin-covered buds, an average run of 12 weeks, and a delicious flavor and aroma profile, this is definitely one of the best autoflowering strains for topping.
Topping your plants, with any strain – photoperiod or autoflowering – can be a great way to increase the final harvest of your plants. But with autos, this must be done carefully, with the right autoflowering strain and only once you have strong knowledge of how it responds to training.
If done correctly, you should see a size and yield increase on the final product. But with that said, auto cultivators should only ever top plants that they have researched and are confident in their choice. Ideally
But hey, there’s nothing wrong with a bit of experimentation. Growing weed is supposed to be a fun endeavor, and if the idea of topping your autos sounds fun, then go for it!