Crop Steering in coco. How to determine optimal EC?

[early4surely]

I hope someone with experience crop steering can chime in to help me out. I have not managed to find the information I need.

My situation:
I have recently transitioned to crop steering in 1 gallon coco pots, under 600W LED, 12 plants per 5x5.
- Irrigation: Scheduled based on the crop steering guide provided by Floraflex. The schedules are adjusted (P2's added or removed) to reach desired dryback percentages.
- Environment: Optimised in terms of VPD. No CO2 supplementation.
- Nutes: Floranova bloom nutrients @ 1.5 ml per liter, which gives an EC of only 1.2. To note, this formula is more or less equivalent to H3ad nutrient formula for coco. Using Floranova as I do not have access to the Flora line. I am using tap water, with 0.3 EC, and adding 0.1 EC of CalMag, so my final EC is 1.5-1.6 (1.2 + 0.1 + 0.3).

The dilemma:
All of the companies pushing crop steering recommend to feed around 3.0 EC throughout the grow cycle, even in veg (for example Athena handbook and Floraflex guides). I understand that 3.0 EC requires a fully optimised environment. If environment is not optimised, EC should be reduced to approx. 2.5.

According to the Athena handbook, when feeding 3.0 EC, runoff EC should be 4.0-6.0.

I am reluctant to increase EC, as historically everyone would say that in coco less is more, and I suspect that companies are pushing high EC to sell more ferts. Ressources such as cocoforcannabis.com, who do not sell nutrients, recommend much lower EC (1.1-1.6) for fertigation.

My questions:
- Is it justified to feed at higher EC in crop steering? Does crop steering enable the plant to optimise nutrient uptake and yield?
- How far can I push my fertilisation to maximize yield (how high of EC), without compromising quality of end product?
- What are the risks of increasing EC? And how to avoid nutrient burn?
- What is the difference in terms of yield if I increase EC?
- Is 4.0-6.0 EC runoff ok? Cocoforcannabis advises that runoff EC should not exceed input EC by more than 0.3.
- Would it be reasonable to double the dosage of Floranova bloom, such as to obtain an EC of 2.4 (or 2.5 with CalMag)? Or do I need to use a different nutrient line to be able to push higher EC? Or should I just keep on feeding with EC 1.2?
- Any other tips for crop steering in coco?

Thank you for any help. I hope we can sort out how home growers can get the best out of crop steering.
Peace. Keep it growing.

 

[mme_oscar]

Hey,

I've never tried proper crop steering but I'm used to Coco. According to me, huge dry back won't work in Coco. Rockwool and Coco are totally different substrates.
Having high EC and dry back will cause issues in Coco (EC wil skyrocket in the rootzone).
I've been sort of using crop steering teaching tho. Nowadays I decrease watering in generative stage while I fully saturate during vegetative stage.

Sorry it's all feeling, no datas to support my claim.

 

[StickyBandit]

Those suggested EC figures can't be accurate because every strain is different, my Ghost Train Haze grow in coco for instance burns the tips at EC 1.5 so you need to up the EC gradually to find the optimum in my opinion unless crop steering is different than normal growing?

 

[goingrey]

Crop steering is a general term that means adjusting environmental parameters to achieve something.

So doing something "for" crop steering is climbing the tree ass first.

First you have to decide what it is you are trying to achieve. Higher yields? Use a higher EC. Higher cannabinoid/terpene content? Use a lower EC. How much higher or lower, depends, take notes and learn what works with the genetics you are working with in your overall environment, adjust according to your desired result..

 

[early4surely]

Yes, crop steering is different in that it optimises the root environment for the plant in a precise way, by regulating the amount of water in the medium at all times. I understand that when all environmental factors are optimised, plants prefer a higher feeding, as they will eat and drink more as compared to plants in less optimised environments. So my questions basically aim to understand how to determine optimal nutrient levels for optimised environments.

Many people also say that LED lights require higher feeding vs HPS lights, even if environment is not optimised. LEDs definitely require more calcium and magnesium.

 

[goingrey]

Yes, crop steering is different in that it optimises the root environment for the plant in a precise way, by regulating the amount of water in the medium at all times. I understand that when all environmental factors are optimised, plants prefer a higher feeding, as they will eat and drink more as compared to plants in less optimised environments. So my questions basically aim to understand how to determine optimal nutrient levels for optimised environments.

Many people also say that LED lights require higher feeding vs HPS lights, even if environment is not optimised. LEDs definitely require more calcium and magnesium.

The proof is in the pudding? Scale the weight, lab/smoke test the bud..

 

[early4surely]

Crop steering is a general term that means adjusting environmental parameters to achieve something.

So doing something "for" crop steering is climbing the tree ass first.

First you have to decide what it is you are trying to achieve. Higher yields? Use a higher EC. Higher cannabinoid/terpene content? Use a lower EC. How much higher or lower, depends, take notes and learn what works with the genetics you are working with in your overall environment, adjust according to your desired result..

Thanks bro, appreciate the advice. So you are saying higher EC will definitely have an impact on quality? I I would like to optimise yield, while maintaining top quality. Any advice on how high I can go before seeing impact on quality? I am looking for a general indication. Of course, I know that dosage is strain dependant.

Note that my canopy is 500-1000 mols ppfd. I guess Nute strength should be proportional to the amount of light received.

 

[goingrey]

Thanks bro, appreciate the advice. So you are saying higher EC will definitely have an impact on quality? I I would like to optimise yield, while maintaining top quality. Any advice on how high I can go before seeing impact on quality? I am looking for a general indication. Of course, I know that dosage is strain dependant.

Note that my canopy is 500-1000 mols ppfd. I guess Nute strength should be proportional to the amount of light received.

Everyone here has tried overfed bud and there is also science to back up the loss in quality..

As for an EC recommendation I think StickyBandit already gave you pretty solid advice.

 

[Hiddenjems]

Thanks bro, appreciate the advice. So you are saying higher EC will definitely have an impact on quality? I I would like to optimise yield, while maintaining top quality. Any advice on how high I can go before seeing impact on quality? I am looking for a general indication. Of course, I know that dosage is strain dependant.

Note that my canopy is 500-1000 mols ppfd. I guess Nute strength should be proportional to the amount of light received.

Nutrient concentration depends on a few things. Dli, vpd, temp, and the individual plants nutrient needs.

It’s easy to see in a dwc setup with no medium. If liquid levels are going down while concentration is increasing, the plants want a less concentrated solution. The reverse applies as well.

 

[early4surely]

Everyone here has tried overfed bud and there is also science to back up the loss in quality..

As for an EC recommendation I think StickyBandit already gave you pretty solid advice.

OK thanks. I also understood that higher feed leads to lack quality. However, I have been tempted to reconsider this understanding, given that reference companies like Floraflex are pushing 3.0 EC. I am reluctant to try, so am seeking to understand if other growers are running 3.0 EC, and whether they are satisfied with the quality.

My current formula is similar to what sticky bandit recommends. I will most likely stick with it.

 

[early4surely]

Nutrient concentration depends on a few things. Dli, vpd, temp, and the individual plants nutrient needs.

It’s easy to see in a dwc setup with no medium. If liquid levels are going down while concentration is increasing, the plants want a less concentrated solution. The reverse applies as well.

For coco, I also evaluate what plants are consuming by measuring runoff EC and pH. Along the lines of how you manage DWC, until now, I have aimed to maintain runoff EC within max +0.3 EC vs. input feed.

Athena (Jungle Boys) recommend to feed at 3.0 EC, and to expect runoff between 4.0-6.0 EC. Obviously, such high input feed EC aims to enable the plant to grow more vigorously. In theory, when all parameters are dialled in, the plant should grow more, and therefore, should consume more nutrients. Accordingly, it would make sense to increase EC. Does this make sense? If yes, how much can EC be increased vs. the K.I.S.S. formula I have used until now?

 

[goingrey]

OK thanks. I also understood that higher feed leads to lack quality. However, I have been tempted to reconsider this understanding, given that reference companies like Floraflex are pushing 3.0 EC. I am reluctant to try, so am seeking to understand if other growers are running 3.0 EC, and whether they are satisfied with the quality.

My current formula is similar to what sticky bandit recommends. I will most likely stick with it.

@LostTribe tried it briefly a couple years ago

Discussion: LED lighting Coco and 3.0ec

For those new to LED and coco (maybe other mediums too not sure??) I have been told by a few folks that they are running very high ec levels (2.5-3.0ec) under Led's and using coco. I have not found much info about why and how they are doing this. I've also read that it is very important to...

www.icmag.com

 

[early4surely]

Anyone with experience crop steering? Any tips would be appreciated. Thanks

 

[Desert Dan]

Thanks bro, appreciate the advice. So you are saying higher EC will definitely have an impact on quality? I I would like to optimise yield, while maintaining top quality. Any advice on how high I can go before seeing impact on quality? I am looking for a general indication. Of course, I know that dosage is strain dependant.

Note that my canopy is 500-1000 mols ppfd. I guess Nute strength should be proportional to the amount of light received.

I run LED and try to keep my ppfd between 700-800 ppfd since I don’t run CO2… occasionally I’ve had runaway colas that get into the 1200 ppfd zone and those nugs are not nice.

I run 1 part maxibloom and some extras… My baseline EC is usually 2.2 - 2.5 going up to 3.0 mid bloom, not because I’m crop steering but because the plants looked hungry. Runoff can get into 5 - 6 EC zone at peak flower, but by then it’s usually taper and finish time.

I’m running coco hempy buckets, so I’m not sure this would be best practice in top feed dtw. However, I routinely water in rooted cuts at the same EC with no issue.

Moral of the story is start low and watch your plants… they’ll let you know. Sometimes I wonder how hot I was feeding before I got an EC meter, let alone testing runoff. Keep It Simple Surely.

-DD

 

[Desert Dan]

I wanted to add that I don’t precharge my coco besides my hard tap water that I expand and flush the coco blocks with… The first few waterings come out with with a lower runoff EC than I’m putting in.

Also, I usually transplant clones with a bloom nute, 2.5 EC veg nutes on fresh clones may give you a nitrogen toxicity on some strains.

-DD

 

[early4surely]

I have been obsessing over finding the ideal Nute formula since forever, and have been using mainly the Head formula. Now, I will try following the professional feed chart provided by GH. See attached.

The chart suggests that EC should be lower when watering multiple times a day.
Feed is increased during end of veg and beginning of flower. Crop steering likewise suggests to increase EC prior to flower and beginning of flower to stack EC in the medium.

To determine optimal Nute strength, I will simply monitor runoff. If EC is below what I am feeding, I will increase the feed. If EC is higher, I will rinse the medium.

 

[Desert Dan]

I have been obsessing over finding the ideal Nute formula since forever, and have been using mainly the Head formula. Now, I will try following the professional feed chart provided by GH. See attached.

The chart suggests that EC should be lower when watering multiple times a day.
Feed is increased during end of veg and beginning of flower. Crop steering likewise suggests to increase EC prior to flower and beginning of flower to stack EC in the medium.

To determine optimal Nute strength, I will simply monitor runoff. If EC is below what I am feeding, I will increase the feed. If EC is higher, I will rinse the medium.

Solid plan! If your runoff EC rises more than a full point increase the amount of runoff per irrigation, frequency, or both.

Good luck!

-DD

 

[Brainsmoke]

Decrease your ec into 2.0 in the early flower, and 1.5 in the final weeks. I run 1.6 all the round and works great for me. Sometimes I run 2.0-1.8 in early mid flower. But in week 5 onward I have to drop to 1.5-1.6
Target your ph accordingly to your runoff. If it tend to up go with 5.8, if it tend to down run 6.3.
And if you want to be safe, do a little flush per week with your solution in half charge.

No worries to little burnig tips.

When I'm running Lucas Formula (GH) i dont use calmag. I think floranova dont need it needer. Calmag is just Calcium Nitrate and MG Nitrate in most times, and you have 4%Ca and 2%MG in Floranova its enouth. I run with leds and never had a defiency without Calmag runing GH basic nutes.

 

[early4surely]

Hey,

I've never tried proper crop steering but I'm used to Coco. According to me, huge dry back won't work in Coco. Rockwool and Coco are totally different substrates.
Having high EC and dry back will cause issues in Coco (EC wil skyrocket in the rootzone).
I've been sort of using crop steering teaching tho. Nowadays I decrease watering in generative stage while I fully saturate during vegetative stage.

Sorry it's all feeling, no datas to support my claim.

Correct, huge dry back will not work in coco. According to the below table, water is available to plants only when there is at least 30% volumetric water content. Water is more easily available above 38-40% VWC.

My coco only holds approx. 50% VWC at field capacity. This limits my ability to play with drybacks as compared to other cocos which hold 65% VWC at field capacity.

My interpretation of the below table is as follows:
- to steer vegetatively VWC% should be kept above 38-40%. So I should target max 10-12% dryback.
- to steer generatively VWC% should be allowed to dry back to 30-38% VWC%. Target VWC% closer to 35% during stretch, and closer to 30% during ripen/flush. So I should target 15% dryback during stretch, and 20% during ripen/flush.

I would really appreciate any help to clarify if my interpretations are correct. Thanks in advance.

 

[Ca++]

EC offers quite the quandary. Different feeds appear differently. My shop once told me of them putting something in one brand, just to get some reliable numbers. It's going to be pretty vital to get it right though, with a feeding regularity that looks a bit like using carrots. That fairly constant moisture content, that never gets near runoff. That being key to why it must be right.

I'm not sure how they spent so long talking about dryback percentages, and never got around to how you measure them.

The safest bet will be what the bottle says. Then see what happens. The link suggested 1.6-2.0 with their feed. I was just reading a light trial, where their dwc was labbed weekly, and 1.8 was typical. Lots of feeds are around 1.5 - 2.0 but it's not unusual to see good grows outside of these numbers.

My oldest truncheon measures up to 2.8 and was replaced by one that can reach 3.6 though it's poorly scaled at the top. The idea of runoff at 5.0 isn't surprising if you gave 3.0 and dried back a lot. However this carrot like method has no run-off. I think it would be quite the fail. If you can even measure that. Which says a lot about how strong it is.