COCO COIR HELP! I think im either burning or overwatering.

[Hmndtyphn]

FIRST off, hello everyone. I am new and very excited to be here (and growing)
so a bit about my setup, im doing a 2x2x3 grow tent
lights HLG 100 V2 3000k
I have a vivsosun inline fan pulling air from the tent and out to a carbon filter. growing in coco/ perlite mix.
temps between 80-74 r/h is 45-60%
I have 7 seeds from a friend who runs a local dispensary, 2 in 2 gallon smart pots, 4 in small terra cotta pots.

This is my first grow ever and my seedlings started off looking amazing. I have made a few changes to the tent (lowered lights, added a fan, switched from blowing air in with the inline to venting air out.)
and had also previously been using a water bottle about twice a day (every 12 hours) to keep the seedlings moist. Then I began watering about every 12 hours until you could see some runoff (my tops of my pot were looking quite dry, but an inch or two down still seemed damp.Saturday they were a week old and I started noticing the tips of some of the cotyledons were browning on the tips. initially I thought it was my lights being too low, so I raised them. Now im worried that I am overwatering, as that symptom seems more realistic (pictures show them bowing in like a U shape, and that doesn't change based on lighting, getting more water etc. I'm taking to light watering once every 24 hours, though I'm now nervous of under watering.... idk... I need help friends!
-Jared

 

[golfnrl]

Hello Hmndtyphn...I don't have experience growing in coco but I do have some experience with over watering. If you haven't already, go over to GWE and check out this link. Or just search how to water cannabis in the search bar. https://www.growweedeasy.com/how-often-water-marijuana

I started out growing with that model of LED that you're using. HLG makes good lights. How far above the plants do you have the light? If I remember right HLG has a chart for how high the light should be.

 

[Tersky]

What nutes? Is it buffered coco or did you buffer yourself? What ph are you watering at? And yes you are over watering. Seedlings need less water than an established plant and by constantly watering without letting the coco dry almost completely you are preventing the roots from needing to search out for water, limiting root production. I usually feed/water once a week with seedlings until i notice the coco drying out faster due to the plant drinking more because it's root system has filled the pot more. Between feedings i mist to keep humidity up. I have found that watering on a schedule can actually stunt growth as plants have a harder time breathing with constantly wet medium. Only water when your plant needs it and that varies depending on size and stage of growth. Early on i water once a week but during flower i water once every couple days.

 

[SoOrbudgal]

Perhaps that light is too intense for the seedlings?

 

[Hmndtyphn]

hi goflnrl, initially I had the light about 10' above the plants. I'm hovering more around 18-20 now, as I got nervous and wanted to back off. the photos show how they were previously, and were they are now. I have looked over the overwatering/ under watering sections of GWE, just nervous and wanted a second opinion

 

[Hmndtyphn]

interesting. do you think I can get by longer than a day with the coco in those tiny terra cotta pots? I backed off to a lot less water, just once about every 24 hrs. should I stretch it to every 48? I check on them regularly. no notes yet, and my ph is usually right around 6.5 as I am using jugs of distilled water to water currently. when misting, I hit the side walls but not the plant, just for humidity.

 

[Hmndtyphn]

I should also state my previous exhaust setup seemed to be filling the tent with air, and drying out the medium quickly, hence why I changed to pulling air from the tent into my filter. I don't know if that has anything to do with it, but before this my drawing medium would dry rather fast. now I am noticing after the change that my top inch isn't dry for almost 24 hrs, and the soil below is maybe a bit damp? just hard to decipher as most of my knowledge is from growing vegetables outside, overwatering was rarely an issue. this is a whole new kinda beast to for me.

 

[golfnrl]

Seems like I remember 14" for flower and 18" for veg with that light. But it did grow some good bud. It's still good about a year after harvest. I'll admit I struggle with hand watering and remain surprised that cannabis can thrive with a lot less water than what I think it needs! I'm learning that 'knowing' what your plants need when they need it, comes with experience. I didn't understand that at first. I have no growing experience outside of my cannabis adventures. With your growing experience my guess is that you will be fine.

 

[Hmndtyphn]

thank you. I'm going to hold off on watering, and keep the lights raised for now. I'll probably water less and less frequently until they start healing up and making new growth. hopefully that'll help. will update in a few days!

 

[Tersky]

I start my seedlings in a solo cup under florescent bulbs and usually transplant after two or three weeks (some strains are slower than others). Your ph is way off but it sounds as if you did not buffer the coco nor are you using cal mag or nutes. Coco has nothing to feed the plant with. It is essentially hydro. Ph needs to be between 5.5 and 6.5 but ideally 5.8-6.3. I start feeding once i see the first set of true leaves but that is if i buffered the coco before hand. Since coco has no nutes in it deficiencies happen fast which is why buffering is CRUCIAL IMO. AND the fact you are using distilled water means your plant is starving. I would spend some time doing research to learn how to grow cannabis in coco. There are many tutorials out there on GWE main site but this is also a helpful piece in understanding why cal mag is so important to coco grows. https://www.cocoforcannabis.com/needcalmag/

 

[Hmndtyphn]

thank you. I do have a ph reader and buffer, just haven't put it to use yet... my friend who also grows told me this would be fine, but I am seeing quickly that our setups are very different. (he's using live soil from a dispensary friend, im just using coco.) I do have General Hydro's Calimagic on hand, and their flora grow trio, but I was under the impression I shouldn't be adding notes until they are much larger. had no idea coco was such a "neutral" substance, the article is very appreciated. at this point, them being almost a week and a half old, what would you suggest? switching and ph balancing my water is no problem, but I have little experience with adding nutrients. I'm nervous its too late in the game

 

[Tersky]

Start feeding with cal mag first, maybe even double up on cal mag to try and buffer coco, though doing so is hard while the plant is in the medium, but not impossible. If growing good weed was easy, everyone would do it. It takes experience so dont beat yourself up. If you lose a plant, that is just part of the learning experience. Im sure the damn plants have a wanted dead or alive poster for me in my early grows because of the many plants i killed cause i didnt know what i was doing.

Also remember that coco is essentially hydro. You will notice any problems faster than soil so taking care of an issue promptly is important. I dont think these are too far gone, just needs some ICU care for a bit. I use the schedule on the website and adjust as necessary. https://www.growweedeasy.com/wp-content/uploads/2014/12/coco-coir-flora-series-schedule.pdf

 

[Hmndtyphn]

thank you so much again...I jumped right into coco/perilite mix thinking it was like any other soil, just less dense to help with airflow. I really was unsure that I was overwatering... this makes more sense. I'm gunna try a 1 1/2 dose cal mag, and water lightly for the next few days. see if that helps out at all. honestly, the most sad looking one is now the happiest, and what was the happiest now looks dried out and burnt. this is a slightly disheartening first go, but certainly a fun learning experience. also, huge props to this site and everyone involved, this has been such a powerful sounding board for helps or just general knowledge.