I purchased one Boston Fern at Lowes at the end of March. It's at the corner right in front of window in the West. But the sun never can reach the plant. It drinks a lot of water. It has been doing so very well.

I bought another smaller one (just one size less than the first one) at a super market. It drank A LOT, I meant A LOT, when the first time I watered it. It started to drink less water already for the second watering period. I kept it also in the West but in a different room, yet it's about 11 ft from the window. It kept browning already at the bignnering of my possession already. Now it's 1/5 browned.

I brought it out in the back of my house (North), thinking perhaps it needs more sunlight than where I put it at.

What's wrong with it, please?