In marijuana ... size does matter

20 Jun 2021

The new ‘extra-large’ autoflowering strains from Sweet Seeds®

When the autoflowering craze hit the marijuana market about 10-15 years ago, many cannabis growers around the world tested this new concept of strains to identify their most interesting characteristics and determine their advantages and disadvantages compared to photodependent strain

A couple of years later, when people knew a lot more about this new family of strains, the growers who had become regular customers of this type of marijuana plants started to become more and more demanding. One of the traits of autoflowering strains that a good number of growers wanted to see improved was the plant’s final size and robustness. So, at Sweet Seeds®, our breeders started working on an appropriate solution. In 2012, our first XL Auto® strain was created. Since that date, we have been filling the gardens and grow tents of indoor growers around the world with tall autoflowering cannabis plants.


In recent years, we released many extra-large autoflowering strains, including some of our classics. Even more recently, two new genetic lines and a re-engineered strain have joined our catalogue, all in XL size. I am talking about the three strains I just harvested on my outdoor terrace for the 2020 season: Crystal Candy XL Auto® (Sweet Seeds® Strain SWS87), Gorilla Girl XL Auto® (SWS82) and Sweet Amnesia Haze XL Auto® (SWS57).

Of all the new releases from Sweet Seeds® for 2020, these are the ones I chose to grow for the outdoor season. And I definitely do not regret it. Plus, best of all, I discovered that they can be ready to be harvested at the peak of summer. Normally, tall plants cannot be grown or harvested every year in less than 10 weeks.


On 20th May, I germinated two seeds from each of the above strains (a total of 6 plants). They were kept indoors for the first 12 days, under two compact CFL lamps of 18 watts each. This is a very weak light but, in the first days, seedlings are very small, so I could keep them in small 200 ml pots. By grouping them together, two light fixtures with the ideal spectrum sufficed to light them for the first stage of growth.

As CFL lights produce very little heat, I was able to keep them very close to the lamps (2 to 5 cm). This initially slowed down the growth of the main stem, which is what normally happens in marijuana plants. But, of course, the use of a good fan blowing air directly onto the plants also helped them start building a strong stem and a compact initial structure. By the 1st of June, they were small in height, but huge in strength and vigour, so more than ready for an outdoor adventure in the amazing summer climate of southern Europe.

So, on the following day, the 2nd of June, they started basking in the sun from 6 a.m. to almost 10 p.m. – when the sun usually goes down in Spain – and making the most of the best 3 months of the year for outdoor growing in this region of the world. This, however, was only done after transplanting to larger pots, to prevent the heat produced by direct sunlight from negatively affecting the small root system of the seedlings. By placing them in 2-litre pots, their roots were much more protected and kept further away from the edges of the pots, where the heat from direct sunlight is more aggressive.

With this method, as roots spread out towards the bottom and sides of the pots for a few days or weeks, young plants can adapt to the new conditions and become able to withstand extreme climate. When all available areas of the 2-litre pots were filled by roots, the plants were ready to face the adverse conditions of a hot summer.


On the 12th of June, 23 days after germination, it was time to transplant them again into their final pots, as flowering was expected to begin. No liquid fertiliser was used at this time, as the soil mix was already rich in nutrients and became even richer when I added an extra quantity of worm compost.

As the strains I had chosen were all autos, I decided to use 20-litre pots, which I filled with the rich soil mix I had prepared, to which I also added about 150 grams of powdered bat guano per plant. My intention was to avoid the use of liquid fertilisers altogether, or use them only a couple of times during the whole flowering stage. By this time, the plants were already showing a nice structure, with Sweet Amnesia Haze XL Auto® being the tallest (about 35 cm) and the other two strains about the same height ranging between 26 cm and 35 cm.

On the 17th of June, the plants started to show clear signs of flowering, with clusters of pistils forming the first flowers. The Gorilla Girl XL Auto® plants were the first to do so, closely followed by Crystal Candy XL Auto®. Finally, just a couple of days later, the Amnesia joined the club. All 6 plants positively responded to the environmental conditions to which they were exposed, especially the 14 hours of intense, direct sunlight.

The natural windy conditions and a very rich substrate also contributed to the plants developing like champions in the first 2 weeks of flowering, so much so that they were able to grow in height from the initial 30 to 40 cm to about 100 to 120 cm. One of the specimens of Sweet Amnesia Haze XL Auto® tripled the height it had before the start of flowering. Indeed, they were much more than just tall plants, they all developed a large number of thick and strong side branches, ready to support the weight of the buds that were about to form.

On the 2nd of July, all six plants had their buds formed, and it was time to decide on the possible use of liquid fertilisers. As the heat came, with maximum temperatures reaching around 35°C on the hottest days, I had to water the plants every day, which caused the substrate to run out of nutrients much faster than what I normally see in my indoor crops. Because of this, I decided to use flowering nutrients on three occasions.


The first was on the 4th of July, the second on the 9th and the last on the 14th, i.e., two or three weeks before the estimated harvesting date. Fortunately, all three strains withstood the heat without significant problems. Luckily, no pests affected my plants this time. As a preventive measure, neem oil and Bacillus Thuringiensis were applied to prevent the moths from laying eggs on the plants, which then turn into caterpillars eating the flowers from the inside. It happened a few years ago and I can assure you it is not a pleasant sight.

During the last third of the flowering period, aromas were already very pleasant and intense on all the plants. This is usually the case with all the strains in the Sweet Seeds® catalogue, as they are bred with a lot of care for their terpene profile in order to obtain sweet and aromatic fragrances in each genetic line.

In the last week of July, resin production was copious in all of them. As expected, Crystal Candy XL Auto® spread out superb subtle aromas evoking the scent of a candy shop. Its bouquet was composed of a bubble-gum and gumdrop background complemented by tones of sour strawberry and ripe melon. Sweet Amnesia Haze XL Auto® had beautiful incense aromas with sweet tones and hints of lemon, wood and nuts, whereas Gorilla Girl XL Auto® had intense, sweet and fruity aromas, with tones of blue cypress and wood, and a citrus and earthy finish.


All plants were harvested on the 28th of July, exactly 69 days after seed germination, i.e., an extra week compared to the harvest time shown in the catalogue, but when you give the plants such beneficial conditions that allow them to develop a large structure, it is totally acceptable (and even desirable) that they need an extra week or two to complete their lifecycle. They were also very easy to harvest and trim.

After 12 days of drying, they were placed in hermetically sealed glass jars, which I opened for only 20 minutes every day for 2 weeks so as to cure my herbs and refine their exquisite aromas and flavours. The total harvested quantity was 785 grams in total for the 6 plants, i.e., about 130 grams per plant, plus a nice block of dry hash I obtained with a 95μ mesh. All in all, these quantities were more than enough for my personal use until my next harvest at the end of the year.

I enjoyed growing these three sweet strains, which I could consume for a few months. Looking back, I was feeling happy for having been able to harvest plants of such quality and abundance in mid-summer, while avoiding the usual problems that come in late summer and early autumn, such as cold and damp. By mid-August already, I had six pots full of top-quality weed.

As expected, Gorilla Girl XL Auto® proved to be the most potent plant. It is perfect for relaxing moments but also a good choice for a night out with friends. Sweet Amnesia Haze XL Auto® is my favourite choice for a day at the beach - very uplifting and energetic. As for Crystal Candy XL Auto®, in addition to being very potent and relaxing, it is also motivating, so I saved it for when my holidays were over and had to go back to work, as it really helps me face boring tasks with a new positive outlook and a very 'sweet' mindset.

Tommy L. Gomez. Photos by Sweet Seeds®

More Advanced Seeds articles to be found in Soft Secrets:

The Wildest Side of Sweet Seeds®

The queen of the garden: Sweet Zkittlez® of Sweet Seeds

Crystal Candy® and Blow Mind Auto®