Help! Seedlings Yellow And Burnt Edges

[Ravensteine]

Hi, I'm a total noob grower. I have had lots of past experience growing other things so kinda have "green fingers" but this is my first actual 'grow'. My plants are about three weeks old but are growing fairly slowly (haven't got their third set of leaves). Temp is 20-25 cel, humidity 30-40. I started with CFLs but am using an LED which is the correct distance away.

So the problem is that the tips of the leaves are crisping up and they are yellowing, the new growth is also very yellow. I thought it may be nute burn and am just giving them ph'd water at the moment. Also could it be calcium deficiency? I did add calmag to their last feed. Any help and advice would be much appreciated

P.S I tried uploading images but can't seem to do it?

 

[Ravensteine]

If anyone can explain how to add photos that may help. It seems you can't upload from PC and I tried inur. No joy... Many thanks.

 

[DemonTrich]

There will be an "upload a file" button to the right of the "post"button.

Imo, your rh should be at least 70%.

What medium?

 

[xenon730]

There will be an "upload a file" button to the right of the "post"button.

Imo, your rh should be at least 70%.

What medium?

yeah but that wouldn't cause yellowing or anything he's describing and seedlings thrive at all different humidities. definitely need a photo though.

it could be nutrient related but be because of over or under watering. need to see it for sure.

 

[Ravensteine]

Sorry, forgot to mention, I'm growing in coco coir.

 

[DemonTrich]

Looks over fed by the burnt, leaf tips.

 

[New England]

PH water to 6.0 and water for a couple of days,then start back on the nuts @ 1/4 strength.Easy does it

 

[greenthumb89]

when you water make sure you get around 20% run off each time to take out any salts if you don't water to run off with coco it's easy for salts to build up.

 

[DrMcSkunkins]

He said he has only fed once, I would say they are just N hungry. I would brew up an AACT for them and then start feeding them veg nutes at half strength their next watering.
It looks to me like they dried out and hardened the roots and locked out all types of nutrients. If you let coco dry out totally one time it causes bad problems a few weeks later, ive done it...
https://www.thcfarmer.com/community/threads/aact-like-you-have-some-common-sense.82725/

 

[Ravensteine]

Thanks for all the feedback guys. Yes I've ph'd the water to around six and always run off a good amount.

Thanks for the advice DrMcSkunkins, never heard of AACT. I read the article and will have to read into the subject more. I think it will take me a while to get everything I need to set it up.

It is possible they dried out once while under the CFLs, that's why I switched to my LED. The CFLs were putting out too much heat in the small area I started them off in while I was finishing building my grow room.

So you think I should go back to a 1/4-1/2 strength feed on their next watering and then just plain water on every other. Also should I be adding calmag? And most importantly; are they salvageable? Have I caused too much damage?

 

[Ravensteine]

Also I'm using Canna nutrients if this helps.

 

[DrMcSkunkins]

Thanks for all the feedback guys. Yes I've ph'd the water to around six and always run off a good amount.

Thanks for the advice DrMcSkunkins, never heard of AACT. I read the article and will have to read into the subject more. I think it will take me a while to get everything I need to set it up.

It is possible they dried out once while under the CFLs, that's why I switched to my LED. The CFLs were putting out too much heat in the small area I started them off in while I was finishing building my grow room.

So you think I should go back to a 1/4-1/2 strength feed on their next watering and then just plain water on every other. Also should I be adding calmag? And most importantly; are they salvageable? Have I caused too much damage?

Never give coco straight water unless you are doing the final flush, feed your plants every watering as soon as they need food.
When plants are smaller I water by weight, I water until water runs out the bottom and then lift the pot every day until it feels lighter but is still moist on top and water again. When the plants get bigger you will have to water every day. Sometimes they will go for almost a week before needing to be watered again when they are small in a big pot.
Coco has no nutrients of its own so if you give your plant straight water it starves it, you want to replace the old food every watering by using fertilizer in every watering and having runoff to help rinse away old salts.

 

[Ravensteine]

Thanks man. I've read many conflicting opinions on this; some say feed every time and some say every other. I'll trust your judgement but start small, like 1/4 strength and work my way up and see how they respond. That sound about right?

 

[DrMcSkunkins]

If you do every other water feedings you want zero or very little runoff when you do the straight water, I feed every time.

 

[greenthumb89]

I wouldn't really say it's a good idea to alternate between feeding and just plain wwater. when yo water you're washing out all the nutrients and they're not being replaced with any new ones so you;re going to see nute deficiency from that. And make sure once you get a decent root structure in the coco to keep it moist this also helps prevent salt build up. when the coco dries out it lets the salts crystalize and thats when you start getting problems. If anything just feed everytime at a lower ppm than you would normally so you can consistently feed/keep it moist

 

[Ravensteine]

Thanks everyone. I've fed them 1/4 strength and they are looking slightly better and are growing slowly (one is twice the size of the rest), time will tell. There are some that will probably have to go as they are too far gone and weak. I'll continue with 1/4 strength nutes every watering and work my way up to half strength and see how they react. Does that sound reasonable? Also I was told to add calmag to every feed, is that necessary? Should I be using it at all?

When you say ppm greenthumb89, you're basically saying feed every watering with lower amounts of nutes like 1/2 strength every watering?

 

[greenthumb89]

Yeah you're deff gonna want some cal mag in there if you're growing in coco. Yeaah ppm just basically means the strength of the solution. *(total dissolved solids). Sounds good with what you're saying once they develop a root ball thats decent they'll take off. A nice thing with coco coir is you dont have to use big containers like with soil , you can use a smaller container and let it get basically root bound and than you start feeding multiple times a day and than youll see hydro like growth. Keep an eye on that tall plant and don't put all your hope in it , males usually grow taller and faster than females so by the time the females are ready to be pollinated the males are already bustin nuts yknow.