Leaf curl and a bit of tip burn. Should I be concerned?

[NotAllThere]

She's an Auto Candy Kush, 22 days from emergence. I know this subject has been covered a million times but the problem's new to me and I'm not really sure of the diagnosis.



Soil is a mix of Fafard potting mix and Penobscot lobster compost about 5:1. Pot's about 4-5 gal. or thereabouts. First fertilization was when she had 4-5 sets of leaves, 1/4 strenght DynaGro Grow and 1/2 strength ProTeks silica. Made her happy.

Light is a Galaxy Hydro 300W (140 actual) at about 10". Temp in the tent is 70-75 degrees.

Next fertilization was 5 days ago, 1/2 strength Roots Buddha Grow and Elemental, plus half a dose of ProTekt. The next day there was a wee bit of tip burn and curling.

Nute burn? Overwatering? I put her on a seedling heat mat to dry the soil quicker, then yesterday watered with plain water, bubbled overnight. I'd just as soon not flush if it's not necessary.

I don't have the means to measure pH at the moment. It's tap water, bubbled to release any chlorine (they don't use chloramine) and it's always done OK with my seedlings.

She doesn't seem to be getting any worse, may even be recovering a bit. I'm not extremely concerned but I'd like to hear the opinions of some old hands about cause, treatment if anything more is needed and what if any effect there might be on future health and yield.

It's my first auto grow since doing some LR2 not long after it came out and most of my photos for the last 5-6 years have been outdoor. A couple of indoor photo grows have done well. Lots of new stuff this grow; LEDs, that particular soil mix, Roots ferts, and auto Kush.

 

[LED Borg]

at a stab, nute burn could be the cause, ph the run off for a proper diagnosis dude, especially if it gets worse, but your temps could also be too cold 70-75F is a tad bit nippy for me, maybe warm her up a bit more bro, some strains like it a bit hotter or they go yellow with the cold

 

[Waira]

.... yeah, that soil might be a bit rich, so the nute's are tipping things just over the too-much scale,... mild nute burn I see on that new growth,... good products though! The Si supp' is excellent, though you don't need to worry about that being too hot,...it has a little K in it, that's all,... half strength is fine if you giving often ( I like to give it with just plain water, in between feeds,--just a preference!), but go full as she gets bigger... Si works best when supplied at constant, sufficiently high levels as it integrates into the cell wall tissues to fortify them,.. lots of other good benefits to Si as well,... dial you nute's back to 1/4 str., until new growth looks symptom free, then as she gets bigger, ease it up again,... Two things are worth the $$ for prevention's sake...a pH meter, and an in-soil type pH probe,... don't bother with those skinny store bought cheapies you see at garden centers-- way inaccurate! best for the money is Accurate 8 soil pH probe..nothing beats an actual in-soil measurement,... the run-off method is notoriously inaccurate,...

 

[NotAllThere]

Thanks guys! I needed a bit of reassurance. I'm usually real light on feedings, maybe a little too light so the nute burn's not something I've seen on my own plants. I'm guessing that the Fafard's nutes plus the compost were about right and the DynaGro wasn't that much extra, but the Roots on top of all that put her on the edge.

Unfortunately a good soil probe's out of the budget right now but I'm picking up pH and EC probes right off. I've been flying blind too long. I suspect some of my more questionable grows have been due to pH.