Leaves curling up, tips turning yellow/brown

[esiarf]

I'm about 2 weeks from seed with 7 plants, 4 medijuana and 3 what look like afghan.

The leaves are curling up, and on 1 of the afghans 2 of the leaves are starting to yellow on the tips with one leaf starting to get some brown on the tip.

I first thought it was heat stress but my temp has been staying around 80 give or take a couple of degrees for the most part. I did raise the light a bit but they are still curling. I'm using an 8 bulb 4' t5.

So then I checked my ph, the runoff was testing out around 5.5, I meant to get some lime today but didn't make it to town in time. I did test my regular tap water and it tests around 7.0 so I went ahead and just flushed them all.

I've been using a weak solution of superthrive and mg starter with my watering up until a few days ago when I did away with the mg starter and added a weak solution of fish emulsions instead.

I do have a good flow of air over the plants as I have a humidifier blowing over them. My humidity stays between 30-40% which I know is a little low, I do have a bigger humidifier I can use if you think I need to get the humidity higher.

My question is this, can a low ph cause leaves to curl up and yellow, then brown on the tips? If so do you think by flushing it with a ph 7 straight water will fix the issue? Also do I need to get my humidity higher?

Here's a pic:


You can see the journal in my signature, it says outdoor grow but I went ahead and included my indoor plants in it as well.

Thanks!

[HazeSeeker]

If your Ph is not right ...your plants cant absorb nutes as well as they would with normal ph ...post some pics ...it will be easyer to help ...
Here's something for the bigining ....

End here is link for posting photos ...if you dont know how ...PIC.
cheers !

[esiarf]

Here's a pic of one of the medijuana's that has it's leaves curling up:

[DEAN420]

raise your humidty because your plants are trying to retain as much water as possible by broadening out there leaves and curling there edges to catch as much water a possible.

Ph should be amended to a range of 6.2 to 6.8

[esiarf]

Thanks thatboydean, I flushed it with ph 7 tap water earlier today and added a bigger 2nd humidifier a few minutes ago. The humidity was 34% and is now up to 42%, the bigger one has a sensor on it I have set to 55%.

I'm heading to wal mart in a few minutes so hopefully they'll have some lime.

Also, how long should you keep them in the dixie cups? I was thinking of letting them go another week or so and moving them to 5 gallon pots.

[esiarf]

No lime at the walmart, guess I'll have to pick some up from the farm store tomorrow. Another thing I wondered is I taped tinfoil to the sides of my light around the plants a few days ago and wonder if it was creating hotspots? I went ahead and removed it, temps are at about 75 with humidity up to 45% now. Hopefully it will be in the 50's tomorrow and hopefully the leaves will go back down to normal.