Looking for some proven techniques regarding dry downs / dry backs. Obviously this would be plant specific, but wanted some general strategies in both veg and flower. Logic would dictate that when in veg, building a strong rootzone is key and as roots do tend to seek out moisture (hydrotropism) - this dry down should be beneficial in this respect. I’ve read quite a few breeders/growers swear by severe dry downs in flower but this seems counter-intuitive as most “living” soil acolytes claim moisture should always be uniform and stay at about 5-10% wet by volume to purportedly keep all the beneficial microbes/insects/worms alive & thriving. So, is this whole dry back thing only really optimal for coco coir, rockwool, etc while using salts, carefully monitoring EC? How about organic soils or soil-less media that are not quite so “living”? Is this primarily for yield? Is it bigger roots = bigger fruits or large/strong roots = better/smellier/more flavorful fruits? What do you think?
I use a peat based mix. I try to never let them dry out completely. Let them get mostly dry but never totally dry.
The one exception is when I’m making seeds I limit the water to like a cup a day as budrot prevention insurance.
Pulling up a chair for this one as i am currently pondering the same thing. There is a lot of mixed information and it is overwhelming to be a rookie just starting off.
Im running royal good kings mix in 1 gal plastic pots, plants are 27ish days old. I water 2 cups every other day when pot feels light but soil is still moist. I aim for 0 run off. Plants are droopy almost 24/7. I try to dry back but i get scared to let it get too dry due to it being organic.
Its getting pretty frustrating but im sticking to the program and taking notes. I cant keep a plant healthy to save my life but its definitely my fault for not following feed chart
It’s a stress technique, is my understanding. You can use drybacks to determine if a plant exhibits undesirable qualities, and, can be used to boost resin production within the plant.
I use peat and air-pots so if I let my plants dry out I have problems.
This being said in hydro I get the most ridiculous results and the plants are pretty much always sitting in water which is enriched with O2 so they don’t get issues.
With air-pots and promix, even in flower I need to water daily until the last week when the plant stops taking up anything I offer, usually flush week anyway at the end of the life cycle.
Each of my tents has dramatic airflow though so I have no “still air spots” in my tents; additionally they vent outdoors so there’s no standing humidity to worry about… usually.
I grow in rockwool and use a Growlink Precision Irrigation Controller (PIC) and moisture probes. So dry backs are a pretty big thing here.
The whole concept of dry backs is based on a 24 hour cycle. So if your growing style requires watering every couple days, this concept is not for you. Soil, or peat based media, forget about it …
I do heavy dryback during stretch (water for about 2 hours in morning, bring rockwool up to field capacity) then don’t water again til next day. Same concept last 2 weeks during finish. This simulates drought stress.
During other times, keep them moist, water frequently, sometimes I’m 10-15x per day. Fertigate from 1 hour after lights on til 1 hour before lights off. Don’t fertigate during lights off. This is the bulking stage, keep your plants happy and stress free and let them grow.
How much/how often/how far to dry back? That’s really hard to determine without probes, but if you get them “heavy” in the morning, and the next morning they are very light and the plants aren’t wilting, that’s about the best you can hope for.
In reality, watering once in the morning to capacity and never again all day is a generative fertigation strategy which should result in improved quality but less yield. The key to making this work is actually getting that overnight dryback each night. If you are only drying back 10% each night then replacing that 10% the next morning, that’s not enough dryback to push the plant into a generative state, so in reality you are vegetative steering the entire time.
Not sure if this helps, but I’m pretty deep into this so lemme know if questions. Good luck!
I usually let them get bone dry before chop…but not during veg or flower.
This is a fantastic reply. Love the way you word things. I agree entirely.
I would add that dry backs while cloning in Rockwood can also be beneficial. Getting it to capacity, dipping a couple days then letting dry back a bit is a great way to see roots really quickly (4-5 days).
It is a strange concept in soil, but I’m a living soil person and I don’t necessarily think it should be the same moisture all the time. There are lots of times I push my soil an extra day or 12 hours and while you do lose some microbes and things, I’ve seen much better root structures this way. I also learned way back when that cannabis would always prefer to be too dry than too wet and I try to be extremely cautious about consistently wet soil. Just my cents.
What about Coco coir?I use Coco and perlite or Just Coco alone.I find that what @Tripl3fastaction says could apply to Coco too.
Thx!
I only purchased the PIC a little less than a year ago, but have been growing in rockwool my whole life.
I quickly realized I was fertigating way too much and generating too much runoff. I used to pick up my blocks to judge water content, and always freaked out when they got “light”. With the probes I’ve learned I can dry back a lot further than I previously thought.
Challenge with rockwool is the plant will look okay up to the point the water content goes too low, then it will just die. There’s no watering the plant back up at that point. So extreme dry backs without probes can be risky …
Crop steering works great with coco as well, as long as you don’t load your pot up with “organics” too. Perlite is fine.
IMO, rockwool and coco are the only 2 growing mediums you can do this with. That’s why those are the mainstays of commercial growers.
Edit to add - key to making this all work is plant vs. container size.
Small plant, big container = minimal daily dryback
Big plant, small container = large dry backs, forcing you to water frequently, thereby not able to extend your drying period. Basically forces you into a vegetative strategy just to keep enough moisture to keep the plant alive.
In my system, about a gallon of media and a 3.5’ plant is golden.
So obviously this works best with clones, as you know how it’s gonna grow and you can pot size appropriately (again, commercial…). Growing multiple strains from seed for first time can be tricky if you don’t know what to expect.
Fantastic responses so far, thanks OG community! My initial thought was that these techniques were more applicable to hydro / dtw media than “soil” or peat based and that seems to be the overall consensus. Experimentation is definitely in order.
@RookieBuds you mentioned the “stress” aspect. Without going too far off topic, that’s a deeper question I’ve been trying to dig into: Which produces the better end product - a completely healthy, trouble-free plant or one purposefully and judiciously stressed? One would think that babying plants indoors - no pests, perfect RH & temp, etc - would enable her to really achieve her utmost potential, but there’s also the theory that growing indoors even “perfectly” is itself a stressor. The plant just doesn’t quite feel right with constricted roots, strange light frequencies, consistent environmental conditions and not a single drop of water ever touching a leaf - and that’s why intersex traits often appear indoors while not expressing outdoors. Good stuff!
As mentioned pot size vs plant size is very important but as a bench mark I do 2 1/2 foot plants in 1g containers and they get 1L of feed water every 3ish days.
IME different types and levels of stress prompt different responses from the plant. I agree that growing indoors will always create some stress from the factors you mentioned. Growing outdoors also provides a set of “baseline” stressors, such as insect predation, unfavorable climate variation.
“Better” end product is in great part a personal choice. For instance, I grow primarily for my mother’s medical use and her lungs aren’t the best, so a smooth smoke and the highest possible THC content is primary. I also have lots of organic living soil stuff going on, which means there’s mold around, so I favor loose bud structure to prevent bud rot.
3 gallons is the minimum for a good grow and harvest.
Clearly yes, even among a same line. Even if the gaps are less wide that between two distant strains.
But it is also very medium specific, even among different type of soils.
A too high rate of clay per example is destructive and harmfully for the roots of our plants when in a “pretty-much-dry” cycle. A correct clay rate (depend also on the content of soil, overall, there is no golden rule really) boost CEC …
Clearly it’s technically impossible to build an algo that can do it. The only way that i see it possible is to use probes (h2o + 0²) with constant datas collected, then a kind of database using profiles (medium + plant’s profiles).
The root system of this plant is not homogeneous in its function and in it’s dynamics. I simplify as fuck but a good start is first to split the “colonizing” roots from the “root ball”, the core.
When you apply a dry cycle, you generally only dry the colonizing “wrap”, that mechanically reinforce and densify the “core”. Typically how the old guard soggers improved their yield, in “hardening of” the clones before just like tomatoes. Useless to say that you need reliable genetics for it.
The hydrotropism, obviously don’t concern the core. But a partial sub-system of the root mass with its inherent functions.
I use severe dry cycles but to screen the shit out mostly. Not to optimize my production.
It’s counter-productive overall (and dangerous for fungus) to lower the sap pressure at the point to flirt with the death of the plant. What i call severe is a positive or neutral phototropism with a medium dried on the whole perimeter. Not trying to kill the plant, it’s pointless even to breed a line that can grow in dry areas.
Sometimes I dry totally the medium (not always, not often) just before the harvest, but it’s more to facilitate the processing of the harvested weed than anything else.
The data is reliable for this context, but totally unreliable without the depth and the exact said volume. 5% in a seedling pot with a medium with high clay rate is not the same game that 5% in 3 gal pot with low clay rate. Just an example to show that you can’t ignore factors on which is based the equation.
Coco dry fast with a high retention capacity. Rockwool contain a lot more of o2 and is neutral (it’s why you use lower PH) … one more time you can’t apply a generic rule to medium that are drastically different.
The type of nutrients doesn’t really matter for dry cycles, it’s more about how they are chelated and built. Directly in bottles or indirectly during a process inside the pot etc …
Dry cycles with the old AN lines is do-able, dry cycles with a line like Nectar For The God is burning your money in your chimney.
Also EC meters essentially monitor the ballast salts with cheap nutrients (not always sold for cheap) ^^
I don’t grow organic at all. And i don’t pretend to.
But there is enough carbon in my soil to be validated officially certified “organic” or “bio”(EU).
It’s vicious ^^
No life : no worry to have with dry cycles but the root’s health.
I don’t even start to talk about trichodermas etc …
The dry cycles ? Not really.
You can obtain a massive root core without it.
No, it’s all about the density of them. And not all of them. Having very dynamic and dense “colonizing” roots on steroids (Si) and a strangulated/sparse nano-root ball is not desirable, by example.
The caliber of the roots don’t really imply performances, it’s more an expression and linked with the phloem type.
Strong roots is very important, overall.
The genetic first.
Then the processing of the weed count for more than the half of the quality.
The other major factor is what is eating the plant : if it’s a dirty feed that let tons of traces on vegetal mass or if it’s a high grade one that the plant eat to the last mollecule very fast. And of course the quantitative aspect, if you saturate the plant with any compound, you will not enjoy it much in the smoke ^^
Everything else is “fine tunning” an already maximized quality.
This is just not true. I’ve grown 5 foot monsters in 1.5g
Well alrighty haha, i stand corrected. How they not getting root bound?
When they are done the roots are one solid mass. But it’s not an issue.
As long as you can dial in feed and water you can grow giant trees in a shoe if you were so inclined.
Much harder in smaller root space, but doable.
I had tomatillo plants that were in 1 gal and they just strangulated themselves and died from the root zone up. Lol