3 week old seedlings problem

Hello everyone. I'm experiencing a problem with 3 of my little plants. They are about 3 weeks from seedlings, under 600w mh on 18/6 light period. The temperature is about 70 (18-21c) lighs off and about 80-85 (24-27c) lighst on. Humidity 30-45% lights on and 50-65% lights off. Plants grow in 2.5 gal pots in coco. They were watered once a week with small ammount of water. The only nutes I was using was Hesi Root Complex (small ammounts). Since about a week they stopped growing and they are curling down and look a bit palely. I tried flushing but it doesn't help. Coco ph is about 6-7. I've got 8 more different strains that grow in the same box and they look much better (the only problem is that they have a bit yellow seed leaves). Can anyone advice me what can be wrong with them ? I'm afraid if I wont do something soon they will just die, and I'm just out of ideas.

Strain 1


Strain 2


Strain 3


ps I didnt know if thats the correct thread for this type of newbie question, so if its not just move it to the plant problem section

heat is to high should be about 70-75 and stop feeding nutes! strain 1-2 has slight signs of nute burn

Thanks for fast reply. 85f temp is at the tops of bigger plants I've got in the box, so temp for this little plants doesnt exceed 75-77. I also think that it might be because of this root complex nute, but I flushed this stuff out of pots. Do you think I should flush them again ? Are there chances that they will fully recover ?

Hesi has no nitrogen. I would not add anymore for now. It is not helping your ailing plants as they claim it will. Live and learn.

gaha said:

Thanks for fast reply. 85f temp is at the tops of bigger plants I've got in the box, so temp for this little plants doesnt exceed 75-77. I also think that it might be because of this root complex nute, but I flushed this stuff out of pots. Do you think I should flush them again ? Are there chances that they will fully recover ?

Click to expand...

erm i wouldn't flush unless they get any worse and ive never grown in coco so idk if flushing will do the same as it dose in soil

it's a very young plant. be extra careful with nutes. i wouldn't use them when they're this young. GL

flush the medium.

water every other day with a couple ounces of water.

use cfls for now, one bulb right above each plant, or decrease power of your ballast and get the mh about a foot away.

plants dont like soil nutes until theyre vegging hard.

Hello again I dont want to create another thread so I decided to post images here. I've got another problem with my plants, and I can't really decide if thats nute-burn or nute deficency problem. Any help will be appreciated, thanks.

pic 1 + 3 is burn, I can't see pic 2 very well

This is all photos of the same plant So I need to flush this one. Thanks for help

Water once a week with just a little water??? NO!

When they are that size you can give them half-strength nute water daily. I'd give them 4-6 ounces a day until they are 8 inches or so
and then bump them up to 8 0z. a day. With those larger pots try to place the water right at the base of the plant. They are only going to
be growing roots until the outer leaves reach the side of the pot, weeks from now. If you would have transplanted into smaller intermediary
pots you would see more growth.

BigSteve.