Just when I think I have it all figured out...spots.

It started with one cutting.  One leaf developed very faint (as in, I almost have to use my imagination) that progressed and got darker and darker, until the end result looked a lot like fig rust.  Since it was one variety, and its been 2+ weeks since it started, I figured it was nothing to worry about.  However, a second fig has developed this.  Again, only one leaf!  The rest of the leaves on the same cuttings look fine.

I checked the bottom of the leaves...no sign of mites or any other pest (other than a few gnats flying around).  It is very dry in our house, and the grow chambers get up to 80+ degrees during the day...but I wouldn't expect problems with grow conditions to manifest in spots, right?

If it helps at all, the two leaves they've grown on are older leaves, and they seem to develop in between the main veins of the leaf.  I'll post some pictures tonight, if it helps.

Thanks

Pictures, always pictures.

There are many causes of spots, many are very similar. 

Gah...I know I know.  My iPod is my camera and its dead, and the charger is at work.  There WILL be pictures...

Darn that Murphy anyway!!!!  Always screwing things up!

Okay....found the girlfriends mp3 player and managed to make this happen...

 
 

The top picture is the newly affected leaf.  The bottom picture is the result of letting it progress for a few weeks.  I'm hoping its just a heat/water issue...because that's easier to fix than a bug issue, I hope.

Too much light?
When you first described it, it sounded like a nutrient deficiency, and I was gonna ask how long the plants have had leaves on them, and if you'd begun fertilizing.
I saw something similar last year when I was hardening off my new plants.
I figured the plants were perspiring faster than the roots were taking up water.

I have not really started fertilizing.  The media has some potting soil in it, and the perlite its mixed with is MG infused.  When I water, I use a rooting fertilizer with hormone, and it's like...2-5-2 or something and I use it at 1/4 strength, so I doubt it is having many effects.  Plus this is only the 2nd leaf out of 20ish plants.

Too much light....now that's a thought.  I run my lamps from 7:30pm-11am...or about 15.5 hours.  I could cut that to 12 or 14 hours.  Could also just be a too much growth.  Our house has super low humidity, and these guys aren't in any type of humidity bin at all, but I figured if that was the problem, it would affect new growth first.  Maybe not though.

At the end of the day, it's only been 2 leaves.  But if it were a fungal/bacterial problem, that can spread FAST, and I want to stay on top of it.

I am no expert at fig growing/rooting but I had a similar issue last year and for me it was related to going from a happy humid environment to a dry environment too quickly.

My question is were the leaves that dried out on the cutting when they were in the happy humid environment?

If they were then maybe the switch to low humidity environment shocked them and caused the issue?

When it happened to me last year, i lost a few leaves on my cuttings when I went removed the humidity tent too quickly. One cutting even lost all it's leaves but the tip stayed green and I babied it all year and it's doing ok now.

Maybe someone with more experience can chime in if such a scenario is plausible.

The switch from humid to dry can definitely screw with your foliage and cause it to dry out/drop.  For your question, virtually all green growth on mine has occurred outside of a humidity chamber, so they're plenty used to the dry air.  None of them have been in a humidity chamber in weeks. If there were a sudden switch I would agree with you.

What type of rooting fertilizer are you using?

What does the under side of the leaf look like? 
Are there any mold spores?

Underside of leaves are perfectly normal.  No bugs, mites, mold, or anything visible to the naked eye.  Fertilizer is made by "fertilome" and is pretty dilute to begin with, and I dilute it further.  No other plants are affected, so I doubt its the fert.

That looks very much like the top leaves on my tree a couple of years ago when I moved it into the sun too quickly without hardening it off properly. The edges continue to dry up and then start to crack. Bass looked at my pics and said sunburn for sure. I unfortunately don't have the pic for comparison anymore, but hopefully one of the experienced growers will be able to verify what it is. I can tell you my tree totally recovered from sunburn if that is indeed what you have.

Hopefully all it is a bad case of sun burn.

I'm tempted to move my lights off of them a bit.  They currently sit between 4-8 inches off the cuttings, but the way they're growing...  Fortunately it'll be pretty easy to adjust that height.  Sounds like that'll be the game plan for now. 

As a few folks are thinking light problems, that's what I'll address first.  If anyone suspects fungal/bacterial problems, please let me know though.  You guys, as usual, are awesome.

If it's a problem from your lamps it's less likely to be too much light than too much heat.  if they're more than 4" from fluorescent lights it's not likely to be heat, either.  If you're using a MH lamp without UV blocking glass it could be UV and it would only affect the parts of leaves at angles close to perpendicular to the direction of the light.