Light Burn? Nutrient Burn? Underwatering? who knows?

[a123456789999a]

First off please excuse the shitty pics, taken with a camera phone. the problem seems to be a yellowing of the tip and the leaves curling under a bit.

AK47 under 110W florescent lamps on 27/0 schedule about 8-12 inches above tops

3 weeks old from seed

Germinated - Rockwool - 6inch peat pots

Watering with tapwater when dry (seems to be about every 3rd day) watering until water is
dripping from bottom of peat pot, letting drip drain.

Soil - Plagron LightMix

Temps 23-27 degrees C

Humidity 39-48%

Adding 5ml of formula per 1 litre of water on a rough weekly basis

please check out the rubbish pics and let me know your diagnosis im noob so i dont trust mine lol
thanks

[TitaniumFox]

My initial thought is that you are overwatering them. Are you sure the pots are draining and drying thoroughly before each watering?

Light burn is not an issue. In fact, you may want to move your lights closer to the tops if the temperature allows. Are you using CFL's or long tubes?

I don't see the yellowing that you're referring to, except a slight brown/yellow spot on the far left picture. Are you 3 weeks from sprout or 3 weeks from beginning of germination? If the latter, how long was your germ period? Plants look stunted if they are 3 weeks from sprout.

You're using 5ml of what formula exactly how often? I don't know much about your soil, but you'll want to see how much fertilizer content is already present. Adding nutrients after 2-3 weeks may or may not be necessary depending on that factor.

Edit: One more question. Look at the bottom of those containers and see if the roots are breaking through the soil. I can't tell from the pictures, but you may be ready for a transplant.

Get back to me with those answers.

[a123456789999a]

Originally Posted by TitaniumFox

My initial thought is that you are overwatering them. Are you sure the pots are draining and drying thoroughly before each watering?

Light burn is not an issue. In fact, you may want to move your lights closer to the tops if the temperature allows. Are you using CFL's or long tubes?

I don't see the yellowing that you're referring to, except a slight brown/yellow spot on the far left picture. Are you 3 weeks from sprout or 3 weeks from beginning of germination? If the latter, how long was your germ period? Plants look stunted if they are 3 weeks from sprout.

You're using 5ml of what formula exactly how often? I don't know much about your soil, but you'll want to see how much fertilizer content is already present. Adding nutrients after 2-3 weeks may or may not be necessary depending on that factor.

Edit: One more question. Look at the bottom of those containers and see if the roots are breaking through the soil. I can't tell from the pictures, but you may be ready for a transplant.

Get back to me with those answers.

the lights are CFL's and they are just under 3 weeks from germination, (19 days to be exact) the germ period seemed very fast. they were ready for the rockwool in about 2 days then sprouted from the rockwool about 4-7 days after that. as soon as the roots popped through i transplanted to the peat pots. the roots are not popping through the peat pots just yet. In a previous post i had a streching problem and a few of em were falling over but a bit of kynar wire and shifting the lights to about 8 inches away seemed to sort them right out. the pictures arnt great but the yellowing is only at the very tip right now must admit it is quite small and only on a few, not on all of the babies.

the formula is actually called 'formula'. its basically a very weak nutrient solution with trace elements and some potassasium. i was recommended it by my local horticulturel store because i was using rockwood. its being used on a rough weekly basis. (every 3rd water ish. so every 7-9 days)

here is a link to the lightmix soil.... Growing Media > Premium Soils > Plagron Light Mix 50L

[TitaniumFox]

I don't really see any nute burn to be honest. I would back off on the watering a bit. Approximate the weight of the pot after watering (you don't need much water at 2 weeks from sprout) and do the same when it's completely dry. Only water when the pot is light.

Overwatering is much more common than underwatering. A grower should always be able to tell the difference based on the frequency of waterings, how much they saturate the soil when they water and how dry they allow the bottom of the soil to become.

Those cotyledons will yellow off eventually. Expect to see them die in the next 1-3 weeks.

Let me know if you have any more questions, or if you don't think overwatering is an issue.

[a123456789999a]

Originally Posted by TitaniumFox

I don't really see any nute burn to be honest. I would back off on the watering a bit. Approximate the weight of the pot after watering (you don't need much water at 2 weeks from sprout) and do the same when it's completely dry. Only water when the pot is light.

Overwatering is much more common than underwatering. A grower should always be able to tell the difference based on the frequency of waterings, how much they saturate the soil when they water and how dry they allow the bottom of the soil to become.

Those cotyledons will yellow off eventually. Expect to see them die in the next 1-3 weeks.

Let me know if you have any more questions, or if you don't think overwatering is an issue.

ok will do thanks (btw i watered them today so it will be wet for about 3 days or so. when i next water i will use weight and use less water. do u think they will be ok for the next 3 days with the water that is in there atm? before changing the amount of water i water with?

[TitaniumFox]

If that's truly the problem, they will be fine. If the signs get significantly worse over the next 2-3 days, post on this thread again (I'm subscribed to it) and we'll look into something else.

[a123456789999a]

Originally Posted by TitaniumFox

If that's truly the problem, they will be fine. If the signs get significantly worse over the next 2-3 days, post on this thread again (I'm subscribed to it) and we'll look into something else.

will do thank you so much

[domin8cs08]

i think its overwatering too. if it doesnt get better its gonna be the soil's pH

[DirtyViperMan]

Over watering. That peat will hold alot of water.
keep'em burnin
DirtyViperMan

[snapperkeeper]

I agree: overwatering.

[a123456789999a]

ok the problem has taken a significant turn for the worse. I havent watered since i began this thread apart from 1 pot of which i used to test the PH of the run off from the bottom of the pot. i have included pics of the ph test, the formulex (my apologies i thought it was called formula) and the state of the poor babies. i havent watered any others, and now the soil is feeling quite dry on the surface down to about 1 - 1 1/2 inches. if the problem is overwatering how would i ammend this? weigh the water and use less more frequently? i also tested the PH of the tapwater and seemed to be nearer the colour of 8. will these recover? how do i get them back to good health? thanks

[a123456789999a]

2 more

[snapperkeeper]

What I would do is change the soil. Carefully remove the plant, rinse the roots and gently repot in a good mixture like ProMix. Also, a pH of 8 is too alkaline. You want it to be in the range of 6.6-6.8. Good luck.