The leaves are drying out and curling along some edges, and they aren't very green (yellowing?).
The unhealthy plant:
You can see the largest dry patch in the first image - the front of a leaf, while the second is the back of a leaf to demonstrate the loss of colour - compare it to the shots below.
Another healthier plant (for comparison):
This plant sat next to the unhealthy one, about a foot away on the same window sill, so conditions should be very similar. Images are again front then back of two leaves.
A few other points that may be relevant
- This is an indoor potted plant, it hasn't been moved in months.
- Fruit has been produced and harvested (although the first few with blossom end rot, as mentioned).
- It's watered with the same regularity as its peers.
- Water isn't being absorbed as much as with its peers - more ends up in the tray underneath, forcing me to give it less water to avoid overflowing.
This is unrelated to the issue raised in another question of mine - that was a different plant.
What could be wrong with the unhealthy plant?
What can I do to help it?