I have a 1 year old Avocado plant, approx 2' tall, have 18 leaves on it. It's recently been quite wilted and the bottom leaves have developed brown tips.
It was started in a grow tent and once I planted it in soil I transferred to a window with direct light and warmth (3-4 months). Now that it's cold out I moved it away from the window to a warmer spot (2 months) which gets indirect light but is quite a bright room.
I've been watering every 2-3 days approx 1/4 cup, testing to make sure the soil is almost dry-dry before watering. The pot has good drainage and doesn't hold much water in the catch tray.
After returning from being away for 3-4 days the plant was quite wilted. I immediately watered, though only slightly more than normal. The plant didn't perk up, so I thought maybe I gave it too much. I've left it now until the soil is very dry and given it a good soak, again ensuring that any extra water was drained off. The top leaves have perked up again, but the bottom ones remain wilted looking.
Any suggestions? Also any suggestions for fertilizer or other additives? Do I maybe need to repot into a bigger container?

Thanks for your help and suggestions.