burnt leaf tips

it's my second grow and about 35 days old...yesterday I changed the light...the weather was a little hot about a couple of weeks ago but now it's alright... the tip of the leaves slowly turning light green and the yellow and burn... I noticed it about a week ago... now it's still going...

Hi guys this is my first grow have been growing in some outside soil mixed with a tomatoe growing pot mix and some perlite has been growing well since july Until now were i have droopy leaves (some leaves the tips are curling) I have probably been overwatering but after 2 weeks of just watering...