It depends on your drying conditions. If you are in low humidity and need to slow down dry, keep roots on, they won’t really benefit you any other way once you pull and hang. Doing this also requires more space which could be hard for some.
A very good argument for not doing a period of dark is that a fair amount of fungi require low/no light and dying plant tissue to grow. If your grow room isn’t well controlled or if you lose electricity to ventilation you could be greatly increasing the chances of post harvest fungal infections.
The one study I’ve seen that kind of gets at this question manipulated light hours during flowering. I think they went as low as 8 or 9 hours light? For all decreased light treatments yield and quality were lower compared to 12/12. This would also suggest the dark period is a bad choice
A lot of plants “determine” their production of biomass and secondary metabolites by the 4th week of flower and I suspect this is similar in Cannabis. Anecdotally, my plants always seem “the hungriest” in the transition from veg to flower and then a few weeks passed flower initiation. I think I have an article or two about this on my computer but I will have to double check.
The ecophysiology behind this is that in natural settings plants need to invest a lot of energy and nutrients into flower production. To successfully flower and complete their reproductive life cycle they need a lot, making offspring is energetically expensive and they want to make as many seeds or flowers as they can while partitioning enough resources to each egg so that seeds can start life with energy reserves. Some plants only flower after reaching a critical point of nutrient concentrations. Cannabis isn’t one of those, but the need to secure enough nutrients to ensure seed survival is a pretty heavy selection pressure.
That being said, I have had good luck with a foliar spray composed of salicylic acid, epsom salt (sulfur and magnesium), calcium. Salicylic acid is a plant defense hormone that if applied foliar in the first 2-3 weeks of flower can increase teichome production and stimulate terpene synthase genes. Epsom salt is good because it adds extra sulfur, and more importantly magnesium. I dont do much calcium in the spray and I’m not sure I will keep it in the formulation for next time. My experience and the research I’ve seen leads me to believe that the important part of calmag is the mag and not the cal. I’ve only ever seen cal problems in hydro, but that could also be a result of the soil i use. I include sulfur as a supplement for terpene synthesis as it is an important component of some enzymes and modified proteins.
I have a hypothesis about the elevated magnesium cannabis seems to prefer and I am happy to share it, but I don’t want to take away from the main thread.
Lastly, the number 1 determiner of cannabinoid and terpene content is genetics in every study I have seen. We know cannabis reacts to environment, but it can’t do what it’s genetics doesn’t have.
This right here is what might be what’s responsible for the accepting or dismissing of different hypotheses in different scenarios, reminding us that it’s the journey not the destination (with weed, is there one?) that opens our eyes more than a pavlovian cause and effect scenario where there is a clear ‘winner’ ie if I do a to b I get c
Edit I bet even now in the apex of human understanding, lol, we will postulate more questions than we have the capacity to learn, it’s always an exciting time to be alive.
I wonder if we don’t secretly have crazier and better research under wraps here, biting off mechoulam et al, I don’t think the government is unaware of the whole shebang, nor that their hand is more powerful than ours, playing with fire
Are you getting that in bulk or using Aspirin? That’s one of the dip switches I referred to. It’s important to ensure a seedling is exposed to this while it has cotyledons, it switches the gene response for life, not unlike a kid getting a vaccine I suppose. I started soaking my peat pellets in a soln of Recharge fortified with Aspirin, chitin, and kelp and it does great things for them.
You can get it from aspirin for sure. I ordered mine from a research company because my formula was written for pure SA.
There are some interesting papers detailing the effects of SA on different plants based on application timing and amount. Thats what I used for the formulation. Interestingly, I dont think applying SA during veg had any significant result on trichomes or cannabinoid production but that doesn’t mean it won’t. They did say that drenching the shoot tissue with SA during the transition to flower did result in higher trichome density and I think cannabinoid concentrations.
Have you used it on different strains before? I have a feeling that some of the effects of SA are going to be specific to specific genetics, which you see with insect and disease resistance/tolerance differences in different strains.
Just wanted to say I love your screen name. Creative!
Interesting about the SA spray. I’m going to have to give that a try. I do already foliar feed with magnesium (usually epsom salt) ever since switching to LED’s because I find the plants seem more prone to magnesium deficiencies with the LED’s (at least IME anyway), so I’ll have to add salicylic acid to the mix.
I usually foliar feed with fulvic acid and kelp (at a 5:2 ratio fulvic acid to kelp. That ratio is important from what I’ve read) during the first couple weeks of flower.
Here is a screenshot of the formulation. Id remove the calcium carbonate because it requires something acidic to dissolve and then you have to make serial dilutions and I dont think it is anywhere near as important as magnesium. The NIS I used is a non-toxic crop seed oil surfactant that helped to make sure the solution stayed on leaves and to help some of the more polar molecules enter the cuticle. I got it on Amazon, but it might not be necessary.
You right about LEDs and mg, but when I’m growing indoors, even with the older ballast lights, I would have to supplement. I think this is related to the photosynthetic capabilities of Cannabis. In the studies I have read looking at light response and carbon assimilation in plants, CO2 concentrations and enzyme activity are the slow step. This plant just chugs photons like frat boys chug natty light. Its insane. Turns out mg is pretty critical to chlorophyll pigment. If LEDs are enriched in PAR, then more chloroplasts are needed to use. This is just a hypothesis, albeit well informed, but using plant physiology principles it tracks
Adding some fulvic and kelp to my dwc was a revelation. The kelp especially is full of growth promotors and plant hormones. The effects I’ve found are particularly noticeable for root growth and branching, but the plants also grow a very dark green, probably due to the increased chlorophyll caused by the kelp. Anecdotally the plants also seem to be frostier with these additions as well.
I’ve heard nothing but good things about using kelp and have had real good results with kelp meal amendments in the past. You nailed it with the growth promoters and phytohormones!
I’ve wanted to do a grow using whole kelp as part of the soil lasagna when doing raised beds. Like 2 or 3 layers of just kelp laid down over soil or mulch and then repeat the layers a few times. Its hard for me to pull the trigger because I know what I get will have to be shipped pretty far and it doesn’t seem sustainable long term.
This is a great idea, you don’t have any kelp on the beach anywhere accessible?
I collect it off the beach here a few days after a storm, so it’s had a few days to dry out, then a trailer load goes a long way! Then I wash it to get the salt off and then let it dry again, and then I feed it through a mulcher and then mix it with my compost. It makes a huge difference to the plants overall health and resilience to stress! It definitely increases brix levels, especially when combined with fulvic and the cytokines significantly increase branching.
There are dry soluble product here in oz, this is the one I use, but there is a few others.
I need to wait until I’m closer to the coast. My philosophy with growing cannabis, crops, flowers, whatever is the idea that the produce reflects regionalism. I think its really cool to see the differences in flower based on soil, environment, climate etc… its the same as terroir in the wine world. Does that mean I miss out on some stuff? Sure. But when I travel to those places I certainly take advantage of what they have.
I hope you do the kelp beds though and I would love to follow along on their progress! Someday I’ll be able to harvest my own kelp, until then I have some friends who are indigenous folk and historically local to the area. I try to pick their brains in hopes of finding the midwest kelp I can collect sustainably.
For the record its not the kelp harvesting I’m against. But the fuel and air pollution required to ship it to me makes me hesitant to buy more and want to look to source local
Plants that have a dry environment tend to produce more resin as well as have a higher concentration of THC due to the fact that they have to protect their buds from dehydration . This pushes the plant to produce more protective trichomes and terpenes, increasing both intensity and taste.
I personally do this because they do not need intense light at the time of harvest.
This also helps keep the temps down and works to preserve terps.
I have used ethylene late in flower to prevent intersex issues and reall like the quality after harvest.
I can’t say much more that that, I have only done this a few times and never thought about its effect on quality.
I think @JoeCrowe will agree.
I think his findings show that trichome density is genetic.
Most studies show no increase in trichome production.
However, we still need to discuss secondary metabolite production.
Cytokinin in the kelp are most likely what makes the plants dark green.
How do I know?
I do not use kelp.
But I do use BAP a cytokinin and I get really dark green plants.
Also
Cytokinin can have an effect on potecy.
I’d be very careful with kelp. It’s nondiscriminatory in what it collects and can easily collect heavy metals, excess sodium and the like. I’ve followed the lead of Brandon rust lately and have avoided kelp tis just me though. I think micros can be had other ways
Greatly point @DirtySlowToes ! Cannabis already does a great job of accumulating heavy metals even at soil concentrations far below polluted levels, we don’t need to help it any.
Brandon is a good guy and knows his shit. I’ve talked with him before and have a lot of respect for both his experience and education. And he is a sustainability guy so I gotta support him!!
Sourcing good quality manure and cultivating healthy soil is the easiest way to manage micros in my opinion. Put the work into growing happy healthy soils and your plants won’t be able to grow poorly
I wouldn’t use just any manure, but a good source of manure is worth more than gold in organic farming. You need to really trust the supplier has let it cook correctly, it doesn’t carry seeds from other weeds, and (for organic) that it doesn’t have any pesticide/herbicide/synthetics in the mix.
If you have been growing or conditioning soil and have built up a lot of organic matter, that can immobilize heavy metals so they aren’t available for plants to uptake. That coupled with a good microbe population and not disturbing the soil will result in the heavy metals being sequestered inside soil aggregates and they aren’t escaping that unless you powder the aggregates. If you are indoors you can always run a saponin wash to clear out metals and salts after a grow.
tis just me though. I think micros can be had other ways