leafs turning yellow with crispy edges

3 weeks into flowering and about 10 leafs in the middle of plant turning yellow with crispy brown edges.. Flowers look good growing good but some leafd are dying. Its the edges getting crispy. What can thid be? They also fall off quick with ouy force.

Please help

More info needed about grow .... Media you are growing in, neuts used how often are you watering, what type of system are you growing in .. As this could be about four things right off the top of my head too much neuts, over watering, PH!!!! Heat... And about a dozen more but we can't help without info