Indoor Drying leaves question

[Surfer Joe]

I have a bubble bucket plant and a soil plant in the same small grow tent and both are nearing harvest. Both are autos but different strains (white widow and northern lights).

They have grown fine without problems so far, but the leaves on the top colas and other top flowering stems of both plants have become dry/brittle and the edges are curved up a bit and the tips break when I bend them.
It affects both the fan leaves and the sugar leaves near the tops of the flower stems. The leaves a bit further down on the branches are still soft and silky.

The plants don't share the same nutes but they are in the same environment, so I am wondering whether the dry leaves are caused by heat, the fan or the natural progression of top leaves as the colas mature.

The tent has a 7 inch oscillating fan that sweeps across the tops of the plants. It sits about one foot away from the plants because the tent is not very large.
I have a 600W dual spectrum hid light in an air-cooled reflector and the light was about 10 inches above the tops ( I have since moved it up to about 16 inches above the tops).
The humidity and temps in the tent average 18-28C and 45-70% humidity.

Since it affects both plants, it should not be due to the nutes.
I suspect the light or the fan, but I wonder if this is also a natural part of the life cycle of the plants.

Also, should I just trim those dry leaves off and let the buds get a bit more light before harvest?
The plants have plenty of other leaves further down on the branches, and I notice that people often show photos of plants near harvest that look like they have been trimmed of most leaves on the flowering branches.

Any advice would be appreciated, as I don't want to screw up a decent grow right at the end. Thanks.

 

[Soylent Green]

Hi Joe, if the plants are near harvest I wouldn't do a thing about them!
It absolutely no problem that your top leaves become a bit crispy!
Its caused by heat, fan and natural progression!
Maybe give us some pictures ;-)
28 is a bit on the high side of temps and at end of flowering I recommend to get that humidity down to avoid mold!
The most important tip, don't cut healthy leaves!
Unless 1-2 days before harvest pre-manicure wont hurt!
Some people prefer a long dark period before harvest!

Happy smoking and growing: Like Weed:

 

[Surfer Joe]

This photo shows leaves that are feeling dry.
A few inches lower, the leaves still feel soft and supple.

 

[UrbanFarmer]

My 60 day wonder did that as well as myAKR's when they didnt like the heat when i had them under HPS. Got dry up top, leaves brittle and some cracking leaves. I dont know if its possible, but try to keep your temperature a little lower if you can. I constantly battle high temps....it sucks.

 

[northendgreen]

This photo shows leaves that are feeling dry.
A few inches lower, the leaves still feel soft and supple.

I have the exact same thing with my Berry Ryder also near harvest, But Im almost positive it is the heat, its a constant battle! Best of luck to you

 

[ripster]

I know you posted your humidity levels, but were they consent like the entire grow? I'm only asking because this sounds exactly like a low humidity problem. BTW, mine do that too. But it's because of my low humidity.

It's not much to worry about at this stage... Now if your getting brown dried up looking spots on her, I'd say that's an MG and Sulfur problem. On your next grow, Give them a 1/4 tsp per 3 gallons of water of Epsom Salt. And no, there is no actual salt in the product....