by Nebula Haze
Grow Journal is Finished! Go to the final entry.
April 9 – Extra mom plant put in a 2’x2’x3′ grow tent under HLG 65 LED and trained to be flat
I had a few extra plants (they were moms for clones for my defoliation side-by-side grow experiment). I also have an HLG 65 LED grow light (4000k) and a 2’x2’x3′ mini grow tent.
This HLG 65 LED grow light (4000k) only uses 65W and has a spectrum to help keep plants short.
A 2’x2’x3′ mini grow tent is pretty small for cannabis plants, but a fun challenge and easy to hide for stealth purposes. I’m using a tent by CoolGrows.
The HLG 65 puts out so little heat that unless your space is naturally hot you can get away using it in the mini tent without any kind of fan to vent heat. Here’s a picture of the last plant I grew in this setup. Big shoes to fill.
Grow Medium
Nutrients
- Vegetative Stage – Dyna-Gro Foliage Pro
- 1/4 tsp per gallon for seedlings
- 1 tsp/gallon after that
- 6.1-6.3 pH
- Flowering Stage – Dyna-Grow Bloom
- 1 1/4 tsp per gallon for the first 4 weeks after plants start flowering
- 1 tsp/gallon after that until end of grow
- 6.1-6.4 pH
- Give plain water for 1-2 waterings before harvest
I decided to take one of the extra plants and train it to grow extremely short like the example I just shared. The 4000k light has a lot of blue which reduces yields a bit but helps to keep plants short, which is the toughest part of growing in this tent. I thought it might be fun to see if I could break my old yield record for this 65W LED (a little under 4 oz).
Here’s the mom plant
I bend all the branches over and tied them down. This plant had an odd structure because it was a mother plant that had many clones taken from her. To make things easier to spread out, I removed a bunch of extra branches that didn’t seem to fit the shape of the inside of the tent.
I tried to fill the entire grow tent in a flat table shape. This plant structure tends to increase overall yields because it helps produce many big buds that are all about the same size throughout the grow tent. That way all the buds get lots of direct light.
This above-view helps you see how I bent everything to fill the space.
April 10 – The next day I initiated 12/12
This is what the plant looked like the next day after all the leaves turned back up toward the light.
Today I initiated 12/12 to get the plant to start flowering (making buds). My goal is to try to get to harvest as quick as possible so it doesn’t have any time to get tall 🙂
April 15 – Starting to see flowers
This plant was germinated a little over two months ago, had many clones taken, and here she is. Plants that are older tend to start flowering fast and this one is no exception.
I can already see flowers (buds) popping up everywhere. Cannabis buds start out looking like little bunches of white hairs.
April 29 – Buds are developing nicely
I’ve just been giving this plant nutrient water and other than that I’ve left it completely alone. It’s developing perfectly. It received vegetative nutrients for the first 2 weeks after initiating 12/12 and in week 3 I switched to flowering nutrients. The extra nitrogen and potassium in the vegetative nutrients help cannabis plants develop well during the flowering stretch with lots of bud sites, but from now on until harvest the plant needs much lower levels of nitrogen.
I’ve noticed over the years that cannabis plants tend to need lower levels of nutrients overall when they’re growing under a smaller/weaker light like this little HLG 65. Less photosynthesis requires less nutrients. The leaves on this plant look a little dark in natural light so I’m now giving nutrients at 1/3 strength. I’ve been giving enough nutrients for one gallon, but mixing it in 3 gallons of water so the plants are receiving 1/3 strength compared to what’s on the official schedule. I’m growing a clone of this plant in another tent under a bigger 300W LED grow light and that plant can handle much higher levels of nutrients.
I’ve started to notice sparkly trichomes forming near the bud sites. The next post will include closeups of the buds. See you soon!
May 6 – Wow, lots of bud growth!
Buds have fattened quite a bit since the last post. I haven’t done anything but give nutrient water every few days and let the plant develop.
Here’s a closeup of a bud. I’m pretty pleased with the trichome development so far. I initiated 12/12 about 4 weeks ago and nearly all the pistils (hairs) are still white, which means this bud is still young. But I see a few hairs starting to darken and curl in, which is a sign that the buds are maturing. Inside the bud, the plant is ramping up THC development. Buds will get steadily more potent until harvest time. Based on appearance, I’d guess we’re about 5 weeks out from harvest.
That’s it for now. Stay tuned for the next update!
May 20 – Buds are thinking about harvest + experiment time!
These buds are starting to look ready for harvest. I am always so amazed when I grow with this 65W LED grow light in this tiny tent. They are a perfect combo.
I thought you might think this was interesting. The buds directly under the grow light are taking on purple tones, while the buds on the edges are staying the more standard orange/green color of buds.
Buds directly under light have hints of purple
Buds on the edges getting less direct light are staying “standard” bud color
Experiment: How does 3-day dark period before harvest affect THC percentages?
I decided to do an experiment with these buds to test how THC changes during the last few weeks before harvest, as well as test whether a 3-day dark period significantly changes the THC percentage of buds.
So today I’m taking a sample of buds and drying them. I’ll take another sample in 1-2 weeks when these buds are ready to harvest, put the plant in a 3-day dark period, and take one more sample. Then I’ll get it all tested in that lab!
Check back for the results!
May 28 – Harvest day (before 3 day dark period)
I took a few samples for lab testing last update, but most of the plant is still here. Here’s how it looks before being put into a 3-day dark period.
I took a few more samples for lab testing. I’ll check back in 3 days!
June 1 – Harvest day (after 3-day dark period)
Half of the plant is gone from the first half of the harvest, but after 3 days in the dark, the parts of the plant left don’t look any different that I can tell.
I took the opportunity to take some bud pictures.
I love how all the buds are not just sparkling but super dense and heavy.
Check back in a few weeks for…
- Pictures of dried buds
- THC and Terpene lab results (including samples from before and after 3-day dark period)
- Dry yields
- Final thoughts!
July 30, 2022
I just realized I never updated this journal on the website so here are the belated results of this grow journal!
Total Dry Yield: 83.87g (2.96 oz)
That’s about 1.3 grams per watt for a 65W LED grow light. Not too shabby!
Lab results
- Before 3-Day Dark Period: 19.83% THC (20.45% total cannabinoids). Terpenes were 13.65 mg/g.
- After 3-Day Dark Period: 21.86% THC (22.5% total cannabinoids). Terpenes were 13.25 mg/g
Wow! Although this is just one test (and it’s important to remember that the THC varies naturally between buds on the plant), it’s pretty stark how much higher the THC tested after the 3-day dark period. Frankly, this is such a big difference I am absolutely going to have to run more side-by-side experiments to see if this is a fluke or not. The terpenes seemed about the same before and after, so I don’t think they were affected much by the dark period.
Final Thoughts
I absolutely love this little HLG 65 4000k grow light. I truly believe it’s the answer to a lot of growers who are looking to make a true microgrow. I want to try growing with it again, but this time with no fan or carbon filter. Just the tent with the light in it. I’m curious how well that would go since that seems like the ultimate in easiness and I think the light puts out so little heat it would work well.
When it comes to the effects of the 3-day dark period, it’s hard for me to even believe how much the THC increased after the dark period. I am already planning the follow-up experiment, which will be much more detail-oriented and based purely on testing this one thing. For example, I will grow separate clones so I can harvest one plant fully and then the other, as opposed to having to cut off buds from the same plant, which could affect the results. For example, what if it wasn’t the dark period but harvesting half the plant that caused it to increase THC in the other buds? Such an exciting time to be a grower!
Check out more side-by-side cannabis growing experiments.
