First Coco Grow Help!

Hello RIU! I’m on day 10 of my first Coco grow and I’m having a few issues. A couple of my plants are pretty light green/yellowish, especially newer growth. All plants are receiving the same regimen, but the issue is appearing particularly bad in 2 plants. It seems like the leaves are kind of divoting and thin too. I’ll post some pics.

Coco was pre-charged. Runoff consistently at 5.5-6.2 pH. EC was started at around 300, mostly with cal/mag and a very light Nute solution (h3ad’s formula). Today is day 10, and I have been increasing the EC by about 75 since day 4-5. Yesterday EC around 800, this morning EC 860.

I am concerned that a couple of the cups have too much Perlite (knocked over the cup and some fell out... replaced that bit with perlite. Wondering if I need to transplant into a much higher coco/Perlite ratio. The aim was 70/30, but some may be as low as 50/50 unfortunately. Any ideas for you experienced coco growers? Btw, temps 77, RH 55%. Good air flow.

Doco,
Need to know what water you're using. The whole Ca Mg issues in coco is important.

...over 800 ppm for that size plant is bad. I feed my small plants at 300ppm or so.

Your plant actually looks like it could use some Mg. But considering your nute level...it could be lockout.
JD

It’s not 800 ppm, it’s around 860 EC (430 ppm). I am using R.O. water.

I have been adding cal/mag plus at 2.5 mL per gallon, 6M/9B + great white, armorsi, and diamond nectar for a full strength mix around 900-1100 EC (450-550 ppm) and diluting down with cal/mag water (around 230 EC). Increasing the concentration as the days pass. I did just increase the height of my lights just in case (they were already at 40 inches but I have qb 288’s x4 boards and x2 drivers). I might have been giving them too much light (maybe around 430 PPFD?) — I am pulling 240 watts out of the wall with them dimmed as low as I can).

For seedlings I would start with quarter of what's suggested and not go beyond half.

Hi Doco,
Sorry about misreading that. EC...I really should start using that rather then ppm. A more universal number.

Well...I don't think the perlite percentage is an issue. People grow in 100%.

Not sure about your additives. Mycos, silica and humic acid. Not bad choices but maybe back off till they are older and larger. My plants don't seem to like the silica I add...different brand.

If you just eliminate them as a test. See if plant does better. Then add back one at a time to be sure one of them isn't messing things up. That's all I can think of at the time. I'd maybe consider a calnag flush before beginning the test.
JD

I did a flush with FloraKleen, followed by a feed at 50% strength, and just applied about a 950 EC Epsom Salt/CalMag/Soap (KOH) foliar spray. We’ll see how it looks this evening after raising the lights, the foliar cal/mag, and a flush and light Nute feeding.

I’d think that if it is indeed a cal/mag issue, this foliar feed should give noticeable results by this evening.

So I just checked on the plants again. Almost an immediate improvement. The leaf that was looking the worst (maybe a combo of light burn and cal/mg deficiency) is already looking much better and the leaves are praying up. I have noticed a significant improvement of the posture and color of the seedlings — likely indicating a cal or mag deficiency. Since I’m growing in coco, I really think this was the problem. I am going to continue twice daily cal/mag epsom salt light foliar feeds until the plants are on full strength feed.

Doco,
One little comment. You seem to have your own very specific way of doing things...and that's cool.

But ask yourself why a seedling would be Mg deficient when clearly you were adding in enough calmag.

It was not being absorbed...and doing a foliar workaround will not cure the original problem.

What Charsi420 said... 1/4 strength feeding at that stage is solid advice and I suggest you follow it. You're locking out Mg somehow and you haven't even discussed ph. Step back and re-assess things. Do it offline so no egos are involved.
Good luck,
JD

Ah hell I don’t care about my ego, I am here looking to ask more experienced people. I have tested runoff nearly every time, it’s around 5.7-6.1. Feedings going in have been as high as 6.3, but weaning down in pH as time progresses.

You don't need to be feeding those seedlings all that stuff and you also don't need to feed them everyday. You should let the coco dry out some with seedlings like that. It will encourage root growth. Don't worry about runoff, worry about what you put in. I've been growing in coco for years and I have never once checked the runoff. It's what goes in that matters. And what you're putting in is too much. Those seedlings don't need any of this "great white, armorsi, and diamond nectar". All they need is quarter strength veg nutes at this point.

What you need to be checking is the PPM. Again I'm regurgitating what I've read here and on a couple of other places, no point chasing and trying to fix run-off PH, you'll only f*** your plants trying to adjust things.

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