Coco EC is hard to dial in without a lot of runoff

Right now, I'm watering at 1.5EC until my runoff is no higher than 2.0EC. My plants look happier than they ever have, but I'm wasting minimum 35% runoff with each watering.

The reason I started with the heavy runoff is my veg plants have always been amazing and they always had (unintentional) lots of runoff. They're in solo cups so it's not like I measure their runoff, I just slop it on there. As a result, they behave exactly as expected and respond quickly to changes.

My bloom plants always got 15-25% runoff and got worse and worse as the grow went on. If I water weak enough to prevent climbing runoff EC, my plants show deficiencies. If I water strong enough to prevent deficiencies, EC climbs and they start off with the tip burn and overly dark green leaves, then progress to a brilliant mix of purple and spotty-banana.

I can partially fix the problem by watering more frequently, but my plants seem to really like a dryout cycle, and it prevents green stuff from growing on the surface. I think Canna recommends letting coco dry out a little bit as well (in one article, I think I've seen them say to water twice a day in other articles).

The extra runoff isn't breaking the bank or anything, and I'm really happy with my plants. But the fact that I need to do this differently than everybody else makes me think I've lost the plot.

Your EC is rising because of the "dryout cycle." If you water twice (or more) per day, your EC and PH remain pretty stable, as long as you water to plenty of runoff. Runoff really is important.

You want coco to be 90% saturated all the time no letting it dry off that is a soil thing not a coco. When you let it dry your gonna get salt buildup causing high runoff ec. Water more frequently and that should help.

Forage said:

But the fact that I need to do this differently than everybody else makes me think I've lost the plot.

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What are you doing different? You don’t water everyday?

Fed every 2 hours current EC 0.8

Highest I’ve been so far 1.3EC

1 plant in 2 gallons of coco.

Wattzzup said:

What are you doing different? You don’t water everyday?

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Percent runoff. Most feeding guides recommend 10-20%ish. People online seem to also be around that area, maybe up to 25%. Normally I'm 30-35% at least, I think last night I was 40%. I seem to be out of step with the rest of the coco people out there.

Forage said:

Percent runoff. Most feeding guides recommend 10-20%ish. People online seem to also be around that area, maybe up to 25%. Normally I'm 30-35% at least, I think last night I was 40%. I seem to be out of step with the rest of the coco people out there.

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At the EC you are running high volume runoff is necessary.

if you halved the amount and increased feeding frequency but reduced feeding volume to only allow a little runoff would probably help you more.

i have NEVER seen an indoor plant that needed EC In coco above 1.5 and that was with 5ft tall monsters.

jondamon said:

At the EC you are running high volume runoff is necessary.

if you halved the amount and increased feeding frequency but reduced feeding volume to only allow a little runoff would probably help you more.

i have NEVER seen an indoor plant that needed EC In coco above 1.5 and that was with 5ft tall monsters.

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My EC is a little wonky because I'm running maybe 1/3 organics in the form of seaweed extract. My PPM (calculated from the numbers on the bottle) is 130/80/130 (and 120/60 ca/mg). I've still found it useful to measure the change in EC between nutrient and runoff, but I think the actual readout is a little higher than the same numbers in all salts.

If what goes in is good that's all that matters. I'm from a different coco camp and don't believe in all this 10-20% runoff. When I was hand watering I never watered to runoff like that. Just until it barely started to run out the bottom of the pot was all I did. Sometimes not even that I'd just keep the coco wet. Sometimes I would even skip a day watering. When using blumats I get zero runoff for an entire grow. Plants have always grown nice and healthy. I run higher than 1.5 EC in flower with blumats and no runoff with no issues.

I'd ditch the seaweed extract and just feed something like Jacks and run with that.

But why are you even checking the runoff if you say the plants have never looked healthier? Worry about what goes in not chasing what comes out.

xtsho said:

But why are you even checking the runoff if you say the plants have never looked healthier?

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Sorry, unclear writing on my part.

The plants started looking healthy when I started watering until the runoff EC dropped.

Forage said:

My EC is a little wonky because I'm running maybe 1/3 organics in the form of seaweed extract. My PPM (calculated from the numbers on the bottle) is 130/80/130 (and 120/60 ca/mg). I've still found it useful to measure the change in EC between nutrient and runoff, but I think the actual readout is a little higher than the same numbers in all salts.

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Coco holds on to very little nutrients which is why you have to feed everyday. Keep the organic nutrients for soil where it’s more useful. Like said already get you some jacks or greenleaf nutrients. Much simpler in coco and many many people have had successful grows with them. Along with what everyone else is saying ec maybe high going in. Definitely water more frequently and you won’t have to have such large amounts of runoff. Less volume more frequently.

What's your environment like? In a warm dry environment/lights close/small pots the ec will climb you'll need to offset that climb with ec, pot size, or frequency of feeding.

If your environment is good and feeding regularly you shouldn't get many problems with the run off.

Star Dog said:

What's your environment like? In a warm dry environment/lights close/small pots the ec will climb you'll need to offset that climb with ec, pot size, or frequency of feeding.

If your environment is good and feeding regularly you shouldn't get many problems with the run off.

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I think the environment's good. It's probably good. At least it's fixable.

In winter I try to keep the night time temperatures from dropping below 18°C/64°F. In the summer I try to keep the daytime temperatures from getting above 29°C/84°F. Generally I dehumidify to 65%RH, but the last 4 weeks of bloom I"ll drop to 50%RH.

Looks good on paper but right now every plant is doing a different funky thing. There's 4 plants, one has it's leaves pointed up at the light like it's praying, one is curled down. Not hooked down at the end claw-style, but curled all the way under (this seems to be getting better as I'm dropping the runoff EC). One plant has the ridge rising on the edges of the leaves, and one is starting to taco. I've got my 600w HPS bare bulb about 2.5' away from the tops of the plants and they're all shaking ever so slightly from two fans pointed at them from the top. I'm gonna get the IR thermometer on the top leaves tonight and see if it looks like heat stress.

My pots are about 6 liters I'd guess? about 80% full? If you water them and let them drip out for five minutes, there's about 3.5kg of coco in each pot. 4 plants in a square that's about 3.6' on each side.