r/fastbuds

A lot of new growth! Topping was an impuls decision lol but I’m glad I did it! She’s gonna be so bushy I love it. Any recommendations?

Hey, this diary entails my experience with Fastbuds and their new strain; Guava Runtz. They have partnered with Mephisto Genetics and this lineage had me curious, almost giddy to try something new and to improve my portfolio regarding plant knowledge, strains and their specific needs, and breaking the “bro science”. A tropical, fruity experience with a distinct mango profile which sounded “exotic” lol. The mashup of this upcoming strain is a result of pairing Guava Auto RF3 (Fastbuds) a Autoflower world cup champion with Mango Runtz F5 (Mephisto). Any questions or suggestions let me know!!

Would love to provide more knowledge or learn some things that would help. Dry started last week Wednesday (8/5/2026) and I’m planning on drying it a little slower than i have last time. I also have a jar curing that was a sampler/ tester that got cut around 8/1/2026 or so and is on its 4th day of cure or so. I got temps averaging 67-71 and rh 45-57 which is the best ive ever gotten it. Learned a few new little tricks and methods in my time and finally clocked in vpd at around .9ishhhh or so. Terps aren’t necessarily lost via airflow itself, but think about the rate of exchange of airflow, the density / layer of water around the bud and how fast thats exchanged, whether its with cooler air thats fast, hot air thats dry. A lot of the cannabis market/suggestions rely on half truths or bro science that needs to be weeded out. Not in some hipster way, but for the betterment and preservation of what this is. Or something..😂 haha jus

My 4th to 5th grow coming around, started May 11th with 2 of these bad suckers in 5 gal pots, used some okay-ish potting mix i had to sanitize, re- microbialize, amend, etc. This grow was quite more sanitary than my last ones and more consistent regarding flushing, watering on time, and making sure i didn’t over feed them. One thing I always knew/ was trying to control was the vpd, the plants constantly perspirated/ transpirated too much throughout grow likely limiting yield or terps which is fine, its a personal grow merely to learn and smoke for scientific purposes heh.. temps during flower hit around 83 max when i was being lazy early flower. Then i kinda amped up fans and turned the ac on to keep this shit from burnin out lmfaoo. Then averaged around 72-77 which is tolerable for me.

Between seed and week 3, the main priority i had for this strain was to keep track of veg, make sure there were no hiccups that stunted lateral growth since this strain has lateral growth that SHOOTSSS sideways and allowed me to train her with low stress/ SOG by week 5-6.

By the 5-6 mark. The buds began to swell, turn purple and stretch. Between the 2, these were more on the moderate yield and seemed to focus on resin production, height and phenotype varying vastly between the 2 also… the shorter one was more compact with the lateral branches almost reaching the height of the main cola, much more purple radiance and vivid purples. Every time I’d open this tent, it reeked of this indescribable smell of.. dank.. sweet guava. Almost a mexican pantry/ tajin and a smell reminiscent of a fruit market, that musky, savory, mouth watering sweetness that hits your nose and leaves you bewildered. Lmaoo maybe a wild turn on words. I am more than pleased with Fastbuds collaboration with Mephisto. The colors are beautiful, might difficult to tell when these are “barely ready” “ready” or “overripe”. Seems this auto was bred with productivity, and management in mind for moderate to pro growers, it is nutrient sensitive, a little drought prone as it is a heavy water drinker during flower, could have had a little more leaves during veg/ gave more nitrogen, i was being careful because once Id overfeed nitrogen, i knew that “earthiness” or “musky grass” taste sometimes gets directly infused into the plant tissues with excess.

The way i could tell it was ready is i had to go based off several factors because autos are a little tricky for “harvest”.. i had to wait for the pistils to brown around 65-80 percent in the mid canopy. Touch the bottom few buds and notice whether they’re beginning to ripen or still overtly grassy. Whether the bottom buds left a greasy resin on my fingers or more sappy and sticky. And more or less.. the usual trichome test with a magnifying glass(I waited for around 5-10 percent amber on mid buds) (15-20 on top buds). Some may say thats overripe for this strain, it was a necessity to get the most yield, potential terps, and honestly since it felt like the most rewarding idea. Also had to plan the sanitation step, messing up the dry or cure would waste around 3 months of prep, feed, wait, and nurture. During the last week and a half, i flushed about 6 gals between 3-4 days each and the last 3 ish days it dried back accordingly.

Additional or misc info:
During the change from late veg to pre flower , i noticed soil began to sink because the potting mix i used consisted of lots of bark and carbon heavy material that began to decompose rapidly due to the easy access to micro organisms, additionally the use of molasses sped their activity up,blah blah i went ahead and added the same soil mix without sanitizing to top it off, nothing really happened until week 8 where i notice some nutrient problems paired with spotting and it arose.. pests hmmmm.. so by week 9ish i added a sand barrier on top snd began to bottom water to make the plant parched near the stem and push the whitefly population back. It worked paired with some yellow traps. Another very sneaky way you can tell theres some infestation is little sparkly dots which is their sap that attracts fungus or soot that may function as attracting moisture, humidity, or merely rotting the leaf its on or the buds the bug poops/ releases saliva on. Its detrimental to the plant. Anywhere you see those sparkles at least wipe or cut if its in excess.

Environmental info:
Week 1-3:
73f-79f, 45-70rh

Week 4-8
70f-87f, 30-45rh

Week 9-12
72-82f 30-50rh