HELP! Leaves are curling up on young plants

[Stevepmd]

Hello,
I have noticed that the leaves are curling up. and wanted to get ahead of the problem. but not sure what the problem is.
Im growing in Coco. and have been watering 2 times a day.
PPM around 450 room temp at 26.
Any ideas would be a great help.
Thanks

[VtGreen1965]

You may be overwatering, twice a day is overkill usually.
Let the soil dry out before you water again and then water in the morning only if possible.
By watering in the morning the plants will be able to put the water and nutrients to more use than watering when they are going to sleep and suspend growing for the night.

[Canuck147]

Don't drown them - let them dry out before watering.

Watering twice a day won't make them grow twice as fast.

[Stevepmd]

Hey Guys,
Have you completed a grow using Coco Coir? From what I have researched about growing in Coco is to never let it dry out and do not treat it as soil and you must water 1 to 5 times a day at first I was that would drown the plants and root rot would set in. So I gave it a try. I have 10 plants from seeding. So I tryed it on 4 plants and I watched them very close and after 2 weeks of watering 2 times a day No problems at all and the the 4 plants are much bigger than the rest ( see Photos below. This problem of the leaves curling up is on just 2 of the plants.