Deficiency or overload?

I'm sure this newby question has been asked a thousand times, but having searched and searched I am still none the wiser! My babies popped up 12 days ago and, bar one, are growing very slowly. The leaves have pale, yellow spots on them. I have fed them once with 1/4 strength nutes, and every watering has been with root tonic. I am concious I may well have overwatered them too. Here's a pic:

FlashBabylon said:

I'm sure this newby question has been asked a thousand times, but having searched and searched I am still none the wiser! My babies popped up 12 days ago and, bar one, are growing very slowly. The leaves have pale, yellow spots on them. I have fed them once with 1/4 strength nutes, and every watering has been with root tonic. I am concious I may well have overwatered them too. Here's a pic:
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Wouldnt recommend using any nutes or tonic yet. Use just water for 2 weeks (or until they have a good 4 leaf sets). Then start at 1/8 strength every other watering and work your way up. Water them every 2-3 days or if theyre close to being dry on the bottom. Theyre deffinatly over ferted which will stunt growth. They might not start growing again for another week or so but I think theyll make it. Also next time you water I would flush out that cube with just water

Thanks man, confirms what I'd feared, I guess newby over-eagerness! I'd heard from a few peeps that due to the coco having nothing, they needed a light fert after they appeared above ground.

Should I flush them all now, or would that do more harm than good owing to overwatering? I already flushed the cube with the germinating seed in, I never meant to put any fert on that but managed to splash a shitload of charged water on it when watering the others so flushed it just to be safe.

Cheers

PS bloke in grow shop said root tonic is worth using right from seed as all it does is encourage a strong root system and doesn't burn the plant - is he talking shit or is that ok?

Well if youre using tap or spring water, there should be enough micro and macro nutes to get them established in the growing medium. I think the NPK of root tonic is 0-10-10 so it would be better to hold off for now. For seedlings I use Foxfarms Big bloom (NPK .01-.3-.2) at 1/4th strength. I would flush now. Overfert is more dangerous than over watering. Shouldnt take much to flush those.

Im not 100 percent sure about the root tonic but better safe than sorry.

Ok, thank you very much - your concise answer and the info about the content of the water is most useful. Waiting for my kids to go to bed now before I can sneak up and tend to the girls. I'm using tap water balanced to ph 6 with malt vinegar btw.

Also, to be clear, I want to now flush with tap water at ph 6, then nothing for 2 days then water again, keep that going til I have 4 nodes then very light fert?

Thats correct. I also forgot to mention that rockwool (if its not flushed prior to use) usually has a ph of around 8 because of lime build up during manufacturing. so flushing now would be great if that step wasnt taken. I hope for the best man!

FlashBabylon said:

PS bloke in grow shop said root tonic is worth using right from seed as all it does is encourage a strong root system and doesn't burn the plant - is he talking shit or is that ok?

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I use nutes from the off with seedlings 1.0 ec,are you sure that no nutes were spilled on the leaves young seedlings burn easy,then after a week 1.1ec

Thanks again for the advice guys.. I've flushed everything through really well. 20 litres over the nine seedlings, this should also provide some humidity from the waste tray.

I don't really understand the ec thing, sorry. is it something to do with measuring salt content or something like that? I don't have any fancy kit or owt so have to eyeball everything.

Everything is looking much healthier today after flushing Tuesday night and starving them yesterday. Plan to starve them today as well then water either tonight or tomorrow morning.

One of the blocks, containing a blueberry, was falling to bits so I carefully removed the 4" block from the plug and root, and potted it up into coco. It seems to love it, and has really come around since then. It looks loads better than all the others that are in 4" rockwool.

The Super Lemon Haze are both looking rather pale, not like the burn I was previously seeing, just looking sorry for themselves with real pale yellowy leaves coming through. Should I consider potting up the best looking plants at this stage, removing the 4" blocks real careful like I did with the blueberry? I figure if I *am* going to remove the blocks I should do so soon before the root system has bedded into the rockwool. Any advice appreciated!