browning leaves

I currently have 3 plants, all the same strain. I am using a living soil blend which was recently top dressed. The plant in the 3 pictures below started showing signs first and is further along than the other two plants. The other two are just now starting to claw on the bottom leaves. The first...

The browning of the leaf tips started at the bottom, hasn’t seemed to spread much towards the interior of the leaves but now one of he higher sets of leaves is doing the same thing. Light is 2ft away from plant soil is basic giixer “1000 watt”. Watered w a shot glass of water every 3 days. Soil...