promix to coco having issues

I have grown in promix organically for years. Recently I took the plunge into coco after some research and advice from a buddy. My decision was based on coco's high performance nature, ease of watering and high oxygen holding capabilities. It just seemed like a great alternative to peat based mediums. So on 10/25/18 i planted 10 or so feminized seeds. They were started in 2'' square pots filled with coco. The coco was from bricks that I rinsed well and lightly charged with GH flora nutes. I should mention i use tap water that has a PH of 6.8 and 78ppm's. The nutrient solution was @ 255ppm and had a 5.8 ph. I did not use Cal Mag in the initial charging of the coco but started using it @ 1/2 tsp/gal in the waterings. I also slowly raised the TDS from 255 up to 600 over the course of a few weeks. Right from the start the seedlings were tall and leggy with very little foliage. I reacted by increasing the notes given and the plants responded well. However over the last ten days i have noticed what i think is a deficiency. If there is anyone who would care to try and diagnose what's going on I would be appreciative.
The plants are under a T5, temp is between 72-78, humidity between 55-65. air movement is sufficient. Lamp are 18-24" above canopy.

Two days ago I transplanted from the 2" pots to these 1 liter nursery bags. The roots were well developed and looked healthy. The coco i used when transplanting was rinsed well and charged with 300ppm nutes and 10 mls of cal mag/gal.

In my brief experience ph and calmag are key to coco because it's an inert medium. I'm pretty much in the same boat as you

They look hungry.And make sure you add 3-4 ml per gallon of cal/mag and water to run off every time.

Maybe make sure they're moist and I didn't catch what you're feeding at unless it's still 255-300 ppm.... which is too light in my opinion. Edit: I see 600 ppm but stand by my advice.. Are you including calmag still?

5.8 seems a little acidic... But not much.

I would feed heavier and drop that t5 down eight inches and see if they respond positively.

Use a little more pH up and more nutes and shoot for 6.2.

That's what I would do anyway.

Good luck!

Definitely want to not miss that cal/mag when charging/hydrating the bricks...IMO very important. Coco grower for over a decade here, and here are my steps.

- If hydrating a brick to be used for seed starting or cloning use 9ml /gal of cal/mag - nothing else.

- If hydrating a brick for transplanting, still use 9ml/gal of cal/mag PLUS your normal veg mix.

-Then I always stay at 3ml/gal of cal/mag for all veg and flower up until week 7ish (cultivar dependent)

Nothing but cal/mag and base nutes at around 600-900ppm veg and maybe up to 11-1200ppm in flower. Unfortunately there isn't a "one size fits all" on ppms.

Always shoot for 6.0 ph and if you miss a bit above or below, you'll still be golden.

HTH - OGH

Agree with the others that those girls are hungry.

imo everyone makes this waaaaaaay more complicated than it needs to be. I use Botanicare 5kg Coco bricks. I hydrate them with the hottest water I can pull out of the tap to kill pests / pathogens. Once it's cooled, I transplant plants into it. When I transplant plants they get 2-3x more water than usual to rinse the new coco. That's the only 'rinse' or 'charge' I do.

All plants, whether they're seedlings / fresh out of the cloner or deep into flower get the exact same strength nutrients - 1.6EC, 5.8pH. I water everything at least 1 time per day if not twice. Once they're in flower I water 5x per day. It's that easy.

Try the coco all mix. I got a bag from root 2 success hydro. A slightly strong for week cuttings so make sure they are well established, that’s the best medium I’ve used so far unless I got a big grow then I use the sublime mix by pro xl

Great responses! I was dreading getting back on here and not seeing any responses. There is so much conflicting information on the cal-mag it's not even funny. Some say to charge coco and add the first two weeks and others, like y'all folks say feed right on through. That is what I'm not clear about. I'm worried about locking out other nutrients by giving too much Cal Mag. Fuck it, i'll take the plunge and keep steady at 3mls/gal and bump notes up. Really appreciative of the responses people. I'll keep ya posted.

On frequency feeding. three days ago i transplanted from the 2" pots to the 1 liter bags. should i still be feeding once per day? or should i be putting them through wet/dry cycles till they can handle one or more feedings per day? Another topic that is all over the board.

a few pics from past grows.

If the strain roots well water once a day.

If the clones were lazy I'd wait til almost dry once or twice.

Thats kinda what i figured. Cant wait to be dialed in and see the glory. love the idea of multiple watering per day. Today i will go and look at supplies for automated watering system that will eventually be used. Final pot size will be 2 gallon. gonna be using 5 CMH 630 this round and I'm gonna try sealed room with CO2 supplementation. 26 pots with two open end 1/4" lines feeding each pot. 3' head. I was thinking 1200 GPH pump. Whats the consensus?

Congrats in moving to CMH.

I wouldn't argue with 1200 gph but I always think go big and dial it down if necessary.

I'm going to be interested as I'm planning on making watering easier any time now.

Mr. MustaRD, Have you checked out that thread by PICO? In it he details a really simple automated nutrient feed system. Make sure u read through the thread cause in it there are some improvements on his idea. Also cheaper ways to build it. You should;d check it out. It's titled "How to make a PVC dripper manifold"

Flood and drain made sense until laziness kicked in but dtw is appealing and lazy.

Hand watering isn't either.

If you didn't buffer your blocks with calmag or it wasn't done at manufacture and is certified as such, then you could have sodium build up. I for years wondered why I had hit and miss with coco until I found the right coco at double the price certified for EU market and then it was hit all the way. Include perlite 30% at least for root aeration, I find that helps and also use grade of rough coir with the fine stuff mixed, not just one of each. I have on advice from professional medium guys that supply major commercial agriculture like viticulture or berry farmers that the chips of coir although having a nice texture are almost impossible to fully flush and buffer out the sodium prior to use because of their volume of chip and one can run into sodium toxicity if too much is in a mix so I don't use that anymore. I find basically no major difference between a majority coir mix and a promix (and for that matter pure perlite or amended soil) on my custom food in the same given system. But its taken me years to get my coir dialed or rather to work out you are wasting your time without the right coir or properly prepared coir. I get the biggest difference in crop based on how I can not limit root growth or plant momentum with any stresses and how much I can oxygenate the root zone with my irrigation method or medium and also keeping things stable. With coir I've learned unless you are buying the right coir off the bat (where it has been prepared properly already), you must flush and flush and flush again and buffer and buffer again and double check your EC of run-off when hydrating the blocks as that will show you which blocks are really full of seasalt (from the air where the coir is made and stored in sri lanka or whereever) and need to be flushed again. Even with the certified blocks I find one in 10 or 20 that need an extra flush but there the run-off will still be reasonably low as opposed to normal blocks from a grow shop or nursery where the run-off of sea salt after first flush can be EC > 4!


So just double check all blocks when rehydrating them and take extra care in finding good blocks from an importer that is sourcing the right blocks from holland (where they've done the flush/buffer thoroughly already) or take extra care in flushing and buffering and redo-ing this until run-off is in a low enough range and you are satisfied all sodium has been exchanged for calcium. If not it will do it for you when you are feeding calmag when growing a crop and your plants will just look nute or PH or water stressed and you can't figure out why..but its because the coir is absorbing calcium and leaching out sodium and your girls are like WTF !?

maryjaneismyfre said:

Include perlite 30% at least for root aeration, I find that helps

Click to expand...

Coco already has exceptional drainage capabilities, just as good as perlite. There is no need to add perlite unless you want to increase cost and complexity.

So after up-potting, increasing feed to 900 ppm and exchanging T5 for CMH630w the plants have responded. Im thinking the biggest issue was the plants simply had outgrown the small 2" pots. Also, being in such small pots, the volume of medium was so little that issues were magnified. In just 3 days, going from 2'' pots to 1 liter nursery bags the roots are already growing out through the bags. Amazing really. Thanks to all who contributed their ideas. They all helped.

So as far as rinsing blocks. I have used fibre dust coco coir. Seems like a good mix of fiber and grounds. I just ordered another brand, "mother earth coco bale". not because I'm not happy with the fibre dust but because i want to see what's out there. The fiber dust when measured has a 499tds and i think around a 7.2 ph. i measured my tap water yesterday after receiving a new upgraded ph meter. Ph of tap water was 6.8 and it has a TDS of 78. So I rinse the coco coir till the run off is reading 78-80. Am I correct in thinking that rinsing is removing the salts from the coco processing? The way i have been and will recharge the coir will be to feed coir with veg solution (6mls micro 9mls of bloom) and 10 mls of cal mag per gallon. I throughly wet the coco with this solution till its like a soupy mix and let sit at least overnight (24 hours) and then drain off excess water and use. Does this sound like a sufficent method to prep coir?