EC for dummies

[Nonannystate]

WOndering if anyone can give me a rundown on EC for growing in Coco or point me to a site which explains it in simple terms for a simple bloke!

I'm mixing prescribed nutes in rainwater from specs on bottles and am getting an EC of 2.0-2.2. (in the can, not measured the run off as i'm not soaking pots. Plants are small.)

Does this mean I adjust the nute quantity to change the EC or try and change the water PH prior to the mix?

I've got no fucking idea.

 

Cheers

[Frank Reynolds]

So EC for coco, I generally go 0.4 - 0.6 EC for seedlings, up to 1.2 EC for Veg Currently I maxxed out around 1.5ec during stretch early flowering for my plants and is where I have been. 

 

Adjusting EC, you can either add more water to the res or less of the a+b, so if 3ml/L gives you 2.0 ec just drop it 2ml/L if you need a bit more you can add after. 

 

Rainwater may not buffer the PH of solution as well, but if you aren't keeping the nutes shoudn't be an issue. 

 

Always ph tyhe nutrient mix after you have achieved your target EC

[Nonannystate]

Thanks mate....

So if I have a watering can half full at around 5lt's mixed nute solution at manufacturers specs and the ec is reading 2.0, add more water to dilute until desired ec is reached?

[Frank Reynolds]

yep, then PH it

[Nonannystate]

Righto...

So am I right in saying that despite what the nute maker recommends regarding dosage, as long as your hitting the desired EC and correct PH your plants are getting what they need?

[Frank Reynolds]

Yeh, you using rainwater means you might hit a slightly lower EC depending on what water the company tested it's nutrients with. But don't stress too much, focus on hitting a specific EC and PH 

[merl1n]

Something I've found is that the 'recommended dosage' is way too high for my setup. My theory here is if you add more nutes, means you buy more of their product.

Like Frank, I've found my growth rate is better at between 1.2 to 1.5, anything much over 1.7 and I'm seeing a marked decline in plant health and that is despite the manufacturer recommending 1.8 to 2.0

Manufacturers often use the theory that we use tap water anyway. Tap water has already been treated (had chemicals added) to make it safe for human consumption. Rain water has an EC of 0. My treated tap water has an EC of around 0.7 to 0.9, even so I still only add nute to make the solution an EC of 1.2 to 1.5.

P.S. Young plants can show a decline if your salts are too high. I often explain it like this '...babies need to be nurtured, not beaten into submission. Start low'n'slow, then slowly increase...' Well, that's what I do.

 

Also here's a chart that shows how pH alters specific salt availability

 

Hope it helps

Merl1n

Edited September 1, 2020 by merl1n

[Nonannystate]

Sweet....

That clears it up. Many thanks lads!

 

Is PH forgiving at all? Obviously as close to the sweet spot as you can but anywhere in the green zone will work?

Also, for coco growers, how often should you flush? When plants are first starting off there's no need to soak the pot? I'm starting and finishing in the same pot. (24lt)

[Frank Reynolds]

Yeh merl,

 

I'm lucky my tap water doesn't show up on my ec truncheon so its under 0.2.

 

In coco ph can be forgiving to an extent as the medium will do some buffering, but ideally you want to keep consistently within the range of 5.8 - 6.1. 

 

Flushing isn't necessary in drain to waste coco if you are achieving 10 - 30% of the amount of water you feed as runoff. You will be flushing and replacing any excess unused salts with each feed. I personally don't think starting off in a larger pot is the best course of action (unless you are using an autoflower) but if you have to do that with coco i'd flush with water once every week or two, but you have to time it with your plants needs if it ain't too big you might end up overwatering it. With the flush i'd jsut give the pot a good drink of plain water then give it some nutrients straight after. 

[Bigbudenergy]

Something I've found is that the 'recommended dosage' is way too high for my setup. My theory here is if you add more nutes, means you buy more of their product.

Like Frank, I've found my growth rate is better at between 1.2 to 1.5, anything much over 1.7 and I'm seeing a marked decline in plant health and that is despite the manufacturer recommending 1.8 to 2.0

Manufacturers often use the theory that we use tap water anyway. Tap water has already been treated (had chemicals added) to make it safe for human consumption. Rain water has an EC of 0. My treated tap water has an EC of around 0.7 to 0.9, even so I still only add nute to make the solution an EC of 1.2 to 1.5.

P.S. Young plants can show a decline if your salts are too high. I often explain it like this '...babies need to be nurtured, not beaten into submission. Start low'n'slow, then slowly increase...' Well, that's what I do.

 

Also here's a chart that shows how pH alters specific salt availability

pHrange2.jpg

 

Hope it helps

Merl1n

Awesome graph Merl1n, thanks mate.

 

 

Yeh merl,

 

I'm lucky my tap water doesn't show up on my ec truncheon so its under 0.2.

 

In coco ph can be forgiving to an extent as the medium will do some buffering, but ideally you want to keep consistently within the range of 5.8 - 6.1.

 

Flushing isn't necessary in drain to waste coco if you are achieving 10 - 30% of the amount of water you feed as runoff. You will be flushing and replacing any excess unused salts with each feed. I personally don't think starting off in a larger pot is the best course of action (unless you are using an autoflower) but if you have to do that with coco i'd flush with water once every week or two, but you have to time it with your plants needs if it ain't too big you might end up overwatering it. With the flush i'd jsut give the pot a good drink of plain water then give it some nutrients straight after.

Frank - I see this advice mentioned frequently to water to run off in Coco, is this the same for fabric pots? My plants aren't too big but I've already overwatered them prior and watering to run off in a 20L fabric pot is a lot of water. My Coco would be wet for days if I did that, so I'm pretty hesitant until they get bigger.

Edited September 2, 2020 by Bigbudenergy