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Crop Steering in coco. How to determine optimal EC?

Rexel

Active member
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.
Don't listen to manufacturers who only want to sell product. They want you to overfeed for profit. Crop steering is utterly stupid in terms of efficiency in my book. More is not better in terms of nutrient strength. It's all about what the plant is able to tolerate and synthesize at the stage of growth and transpiration rate.

Like we did back in the day it's better to dial in nutrient strength according to plant response and following growers journals from real world practice.

I most often end up feeding 5-6 times a day depending on light schedule at 1.0-1.2 EC in flower. I only feed what the plant let me and its better to stay at the lower end to keep mineral sensitivity and optimal uptake. Cannabis doesn't like drastic changes and feeding high EC that constantly fluctuates with "drybacks" will leave sub par results.

I don't agree about the repeated droughting practices. Arguable that droughting can have negliable positive returns in late flower in a very controlled setting but it will always be terrible for nutrient uptake and keeping the root zone stable.

As a general rule I try to keep runoff below 1.8 EC on sativa dominant strains. How one take a runoff reading is another question but the reading should be taken of only the last couple of drops or deciliters of the total runoff. Taking the reading at the start will only give you a very false reading.

Currently I feed 1.0 EC 5 times a day in Coco Coir and runoff comes out at 1.4-1.5 EC. If you need to feed 3.0 EC on the input to keep the plants healthy and green you're not doing a very good job in terms of efficiency and making the nutrients available for uptake in my book.

Cannabis likes tailored meals at the lower end for optimal growth. Like humans, force feeding is very contra productive for optimal performance.
 
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Ca++

Well-known member
Don't listen to manufacturers who only want to sell product. They want you to overfeed for profit. Crop steering is utterly stupid in terms of efficiency in my book. More is not better in terms of nutrient strength. It's all about what the plant is able to tolerate and synthesize at the stage of growth and transpiration rate.

Like we did back in the day it's better to dial in nutrient strength according to plant response and following growers journals from real world practice.

I most often end up feeding 5-6 times a day depending on light schedule at 1.0-1.2 EC in flower. I only feed what the plant let me and its better to stay at the lower end to keep mineral sensitivity and optimal uptake. Cannabis doesn't like drastic changes and feeding high EC that constantly fluctuates with "drybacks" will leave sub par results.

I don't agree about the repeated droughting practices. Arguable that droughting can have negliable positive returns in late flower in a very controlled setting but it will always be terrible for nutrient uptake and keeping the root zone stable.

As a general rule I try to keep runoff below 1.8 EC on sativa dominant strains. How one take a runoff reading is another question but the reading should be taken of only the last couple of drops or deciliters of the total runoff. Taking the reading at the start will only give you a very false reading.

Currently I feed 1.0 EC 5 times a day in Coco Coir and runoff comes out at 1.4-1.5 EC. If you need to feed 3.0 EC on the input to keep the plants healthy and green you're not doing a very good job in terms of efficiency and making the nutrients available for uptake in my book.

Cannabis likes tailored meals at the lower end for optimal growth. Like humans, force feeding is very contra productive for optimal performance.
Crop steering isn't about increasing feeds. Maybe some aspects are, but others are reducing it. Without steering your plants, how would they ever get from veg to bloom? You use a timer to steer your crop in this instance. I dropped my temps for the final leg, to bring out the purple colours. Crop steering is about changing anything, to move your plant in a certain direction. It's not a new topic.

If you are putting ec1 in and it's mixing with something to produce 1.5, then what did it mix with?
Frequent watering is always done at a lower EC, as ec1, 5 times a day, isn't ec1, once a day. It's 5x more feed. Feed reductions based on frequency are found on some common feed charts.
 

Rexel

Active member
Crop steering isn't about increasing feeds. Maybe some aspects are, but others are reducing it. Without steering your plants, how would they ever get from veg to bloom? You use a timer to steer your crop in this instance. I dropped my temps for the final leg, to bring out the purple colours. Crop steering is about changing anything, to move your plant in a certain direction. It's not a new topic.

If you are putting ec1 in and it's mixing with something to produce 1.5, then what did it mix with?
Frequent watering is always done at a lower EC, as ec1, 5 times a day, isn't ec1, once a day. It's 5x more feed. Feed reductions based on frequency are found on some common feed charts.
I was talking about the kind of Crop steering that OP described. It's two words that can mean many things. Who needs feed charts when you got plants in front of you showing expression to your inputs?

Follow plant response, not general rules. Learn from other growers methods and mistakes and try different approaches to make up your own mind.

Depriving a plant of nutrients in the latest stage of growth for added color is not advisable in my book but each to their own.

Most people who use the herb medicinally make and use concentrates nowadays and that the plants inability to create chlorophyll and photosynthesize properly doesn't show up in the end product doesn't matter at all doing concentrates. Turnover might be slightly faster if you intent to sell flowers but total Cannabinoids and yield will be lower and I don't buy that.

I'm a medicinal grower growing my own medicine not a consumer and couldn't care less what the commercial market wants. I try to breed out the purple in my own plants since it's a genetic defect for good and the bad depending on what you're looking after. I only grow for the widest range and total amount of Cannabinoids/Terps for medicinal use.
 
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LJ farming

Well-known member
Indoors everything we do is crop steering in a sense. From light intensity, environment, C02, nutrients, lollipoping, defoliation, etc.

I run coco multi feed DTW and for me less is more to an extent when it comes to EC. I typically run 1.0-1.8 depending on growth stage. I only check runoff maybe once a week these days unless I am having a problem. My ole head mentor taught me that when feeding correctly again less is more as well as runoff EC should be slightly lower than input and Ph should be slightly higher. This is how I know the plants are utilizing what they are fed.

Peace
 

Ca++

Well-known member
Worth saying, that EC2.5 is likely a hydro figure. EC3.0 almost certainly DWC. EC1.5 or below, suggests a substrate that holds food, and a dryback is expected.

In hydro, it is what it is. The tank EC, will probably be found at the rootzone. It may be the same thing. Roots actually in the tank.
Coco isn't like that. It holds on to feed which the tank doesn't show us. Even the run-off doesn't show us what it held on to, as it didn't come out. However, we do get to see accumulation at work. The more the substrate accumulates, the less you need in the feed water. To get the EC at the root you want. Which means watching the run-off.

I have both coco and hydro versions of the same feed here. The coco tells me 1.5 and the hydro tells me 2.2 which is 50% stronger. Both are trying to achieve the same thing, in different substrates.


A lot of the papers we read are DWC, as the people funding them don't want a lot of substrate to buy, treat, dispose of. That much work can turn into it's own task. With landfill bills, or an incinerator plant. This was why rockwool first fell from favour. Coco replaced it somewhat because it's reusable. It added some drought resistance, and ultimately it can be burnt. These were savings that lower profit facilites couldn't ignore. DWC is next level in handling terms. So most research go's towards making DWC work. This means the figures we see, are those the roots want, but might not be what you put in the tank to achieve this. This is the best set of figures we could ask for, as it's what the plant needs feeding, not the soil or coco. Which means the grower must modify the baseline figures, to suit their individual circumstances. Coco is a long way from DWC


If we read the papers, buy some powders, and try these figures in coco, it will likely be a disaster. It doesn't make the paper wrong though.
 

Mate Dave

Propagator
ICMag Donor
Veteran
I think with Coco you've more complex things than the basic NPK solution itself to add nutriments to your plants. It encompases more ecologiczal recycling with coir so really much deopends on your chosen methodology.

I see no difference in my Tanks in a side by side with same genetics clones DTW and recirculation. One costs more in time, nutrients and water and amendments.

Things can be added to the coir to slow release, as they are not dissolved or released back into a solution they therefore don't conduct E.C. Reducing the need for essential fertigation. These things can maintain pH and an array of other plant functions during a dryback/ recharge.
 

XYZVector

Active member
Everyone gets stuck on crazy high EC as the only way , when its not the only way to accomplish the same goal, and probably not the best option in coco at least. You control the environment, you control the amount and type of growth. I got a feeling a fertilzer maker/seller brought crop steering to the weed world, its normally just called hardened off growth or rank growth in the nursery/greenhouse industry.
I used to think like you did, and your some what correct. However you might be equating inflow ec with pore ec. I am only feeding at 1500 uS/cm, yet my Pore ec is about 10,000 uS/cm. So let's not get these terms confused. Pore EC is not a real number that is easily measured. It is a computed number as I said earlier using the Hilhorst method. Here is a link to Media Sensors explaining how this works, or at least what I found that got me into doing this method. Also if it doesn't work for you RuBp you don't have to do crop steering. I do and I like it getting way better flower with it than without it. Oh and my runoff ec is only 1550-1600 uS/cm so I am not starving the plant of nutes or overdosing it either. These numbers are for flowering plants.

I have plants in veg that show completely different numbers. On my veg plants the infeed ec is 1500 uS/cm, but the pore ec is only 195-400. The runoff ec is low, and this is showing me that the plants are uptaking a lot of nutrients. The runoff proves it as it is only 500-600 uS/cm. I could feed my plants higher EC nutrients without burning the plants. However this is where I do agree with you RuBp. If I do feed the plants more nutrients then the plant has to work harder to get the water out of the media. In veg I want the plants to put on as much bio mass as possible in the shortest amount of time without exposing the plants too much nutrients. This works with VPD to control how hard the plant has to work to get the water out of the media. The nutrients the plant will take when it needs them in the ratios that it needs them if they are present and in a bio available form. If I had to run a higher VPD I would lower the infeed EC to allow the plants to cycle more water without having to create alot of sugars to maintain the EC gradient in the roots. If I had to run a lower VPD I would increase the EC so they can get the nutrients they need.
 
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Hiddenjems

Well-known member
I used to think like you did, and your some what correct. However you might be equating inflow ec with pore ec. I am only feeding at 1500 uS/cm, yet my Pore ec is about 10,000 uS/cm. So let's not get these terms confused. Pore EC is not a real number that is easily measured. It is a computed number as I said earlier using the Hilhorst method. Here is a link to Media Sensors explaining how this works, or at least what I found that got me into doing this method. Also if it doesn't work for you RuBp you don't have to do crop steering. I do and I like it getting way better flower with it than without it. Oh and my runoff ec is only 1550-1600 uS/cm so I am not starving the plant of nutes or overdosing it either. These numbers are for flowering plants.

I have plants in veg that show completely different numbers. On my veg plants the infeed ec is 1500 uS/cm, but the pore ec is only 195-400. The runoff ec is low, and this is showing me that the plants are uptaking a lot of nutrients. The runoff proves it as it is only 500-600 uS/cm. I could feed my plants higher EC nutrients without burning the plants. However this is where I do agree with you RuBp. If I do feed the plants more nutrients then the plant has to work harder to get the water out of the media. In veg I want the plants to put on as much bio mass as possible in the shortest amount of time without exposing the plants too much nutrients. This works with VPD to control how hard the plant has to work to get the water out of the media. The nutrients the plant will take when it needs them in the ratios that it needs them if they are present and in a bio available form. If I had to run a higher VPD I would lower the infeed EC to allow the plants to cycle more water without having to create alot of sugars to maintain the EC gradient in the roots. If I had to run a lower VPD I would increase the EC so they can get the nutrients they need.
I have a veg room that gets cold cold in the winter. Always causes issues around Jan-feb. I ended up lowering light intensity, and raising ec and although growth is slow, but no more nutrient or light burn issues.
 
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