In this report, we’ll outline our experience growing Jack Flash Regular seeds. As a cross between Jack Herer, Super Skunk, and Haze, this strain is a 55% indica-dominant hybrid known for its height, yield, and potency and we certainly weren’t disappointed. A remarkably tall strain, it isn’t ideal for everyone but if you have the room, you’ll love it.
Total growing time: 98 days
Flowering time: 83 days
Final height: 147 cm
Final yield: 132 grams
THC content: 17.8%
To grow our Jack Flash, we kept our plant in an 8-litre plastic pot filled with BAC Lava Mix under a 1000 W Phillips GreenPower HPS light hanging 3 metres off the ground and on an 18/6 light schedule. Our grow space was kept at a stable 23°C during the day—dipping down to 21°C at night—and the relative humidity was a consistent 65% during vegetation.
Germination & seedling
To get things started, we first needed to germinate our seeds. To do this, we used the industry standard paper towel method. Simply place a damp (not dripping wet) paper towel onto a plate and sprinkle a few seeds on top. Then, cover these with another damp towel, place the whole thing loosely under a plastic bag, and leave it in a warm place for a day or so.
After about 24 hours, our seed had cracked open revealing the taproot. The recently germinated seed was then planted into a Rockwool cube (taproot down) and placed under a 600 W lamp so as not to overwhelm it in its delicate state. After three days, we gave our plant her first watering with 100 ml of pH-balanced water (pH 6.0; EC 0.8) with only a small dose of root stimulator added in.
By the end of the first week, our little lady was looking happy and healthy. While she still hadn’t sprouted any true leaves, she was standing about 5 cm tall and the cotyledons were a vibrant green. At this point, it was time to plant her in the 8-litre pot under the 1000 W light.
Vegetation
Over week two, our Jack Flash plant grew only slightly, reaching a new height of 8 cm. However, she also developed her first true leaves and was already sprouting a second. During this week, we began daily feedings with 200 ml of water (pH 6.0; EC 1.7) mixed with Bio Grow liquid nutrients.
As we made our way through week three, our plant hit her first major growth spurt climbing to 18 cm and developing several new sets of leaves. At this point, we increased the amount of water to 400 ml per day and hung satchels of Neoseiulus californicus and Amblyseius swirskii from the lower branches.
These little packets contain tiny predatory mites that live symbiotically with cannabis plants. They do not harm the plant at all and feed on parasites such as spider mites and thrips that can devastate an entire harvest if not dealt with early. These satchels are replaced every four weeks to ensure a constant supply.
Week four saw more rapid vertical growth with our lady reaching a new height of 37 cm—more than doubling in a week. At this point, it was becoming apparent that this hybrid strain definitely favours a sativa growth pattern with long branches and large internodal spaces. To help her keep up with this rapid growth, we again increased the water to 800 ml each day. Also, with flowering approaching, we slightly lowered the humidity to 60%.
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Flowering
Over the course of week five, our Jack Flash plant exploded with new growth and grew to a height of 53 cm. Knowing just how much many sativas like to stretch in their flowering stage (many double or even triple in height), it was time to flip our plant. Doing so was a breeze as we simply needed to switch the lights to a 12/12 schedule. Additionally, we swapped to Bio Flower liquid nutrients and upped the volume of water to 1000 ml per day (pH 6.0; EC 1.8).
In week six, vertical growth slowed down slightly and our budding beauty grew only 17 cm to a total of 70 cm—still incredibly tall for a plant that’s only a week into flowering. By now, the lateral branches had developed nicely and were forming a fairly consistent canopy growing relatively close to the main stalk. Anticipating even more growth in the coming weeks, we increased the amount of water to 1500 ml per day.
Week seven saw absolutely tremendous growth with our Jack Flash growing a staggering 38 cm (in a single week!) to reach a height of 108 cm. By now, the tips of branches were growing their first proper flowers as little balls of white pistils began to appear everywhere. These were still quite small, but they were seemingly everywhere and painted a picture of a bountiful harvest to come.
In week eight, our plant hit her last major growth spurt and grew to 132 cm. During this week, she also began to fill out her flowers; the entire plant was covered in small white buds growing larger daily. The flowers weren’t terribly dense at this point, but their size and prevalence were notable.
Week nine saw minimal vertical growth; only 9 cm. However, the buds were developing quite nicely. By this stage, they were beginning to grow denser and seemingly every possible flowering site had grown a respectable little nug. By now, some of the lower branches were starting to be weighed down by their rapidly growing flowers.
In week ten, our Jack Flash plant finally reached her maximum height of 147 cm. This towering lady was a sight to behold with massive colas growing from the top of each branch. The lateral branches were still mostly standing on their own, but they would almost certainly require extra support soon. At this point, there was nothing left to do but wait for nature to run its course.
By week eleven, the pistils were beginning to turn orange as the buds started to ripen. The flowers were so heavy by now that many lateral branches (and even the main stem) required additional support.
Week twelve saw more of the pistils begin to change colour and the plant was very nearly ready to get cut down. Over the next two weeks, we simply left it to finish ripening until it was ready for harvest.
Finally, in week fourteen, our Jack Flash plant was finally ready to be harvested.
Harvest
Harvesting our Jack Flash was a piece of cake. All we needed to do was cut the plant down at its base, remove the fan leaves, and hang it upside down in a 15.5°C room with a humidity of about 50%. After around 2 weeks, the branches were dry enough to snap when bent and it was time to trim up the buds.
Once the flowers had been trimmed, they were placed into glass jars which were initially left open for 24 hours. Once the bulk of the moisture had evaporated, these jars were closed and then “burped” several times a day for around an hour each time. The frequency of these burps was gradually reduced to only once a day over several weeks until the flowers reached the desired consistency.
In the end, we were able to harvest a genuinely impressive 132 grams of dried flowers with a respectable THC content of 17.8%.
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Terpene profile
The first thing we noticed when we tasted Jack Flash was the distinct citrusy flavour which was slightly (and pleasantly) surprising as the plant didn’t have much of this aroma during growth. Alongside the citrus, there were also hints of berry, spicy hashish, and a pungent earthiness. While growing, the smell of this plant was fairly noticeable with a sweet berry and floral mixture covering a more sour, almost diesel-like, aroma.
Almost immediately after sampling the flowers, the incredibly sativa-like effects became apparent. A cerebral buzz and overall euphoria were combined with an energetic chattiness that had the room rolling with laughter. If you’re looking for a social lubricant, this strain is a great choice. The high was fairly long-lasting so be careful if you’ve got plans later on.
The outcome
Overall, this strain was a pleasure to grow, if a bit demanding. If you’re looking for an incredibly productive plant, this is one of the best options on the market. However, due to its explosive growth and towering height, it may not be a suitable choice for growers with limited space.
- Disclaimer:Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
