I have two tomato plants (Mexico Midgets) planted in a large container full of Miracle Gro potting mix. I know it's a total newbie gardener move to plant two tomato plants in one container, but... it's definitely too late to move them.

Anyway, they've been peachy keen until recently, and now their leaves are curling, turning brown, wilting etc.
It's still flowering & putting off fruit, though that fruit is not mature.

I feel like an idiot but I've tried watering less (we've been getting a giant amount of rain), feeding more... I don't know what to do!

Hard to tell for sure from that photo, but that looks like it could be fertilizer burn, or sun or wind burn. There appears to be some yellowing on the leaves next to the little finger of the hand holding the leaves and that could be an indicator of over watering. The brown edges could be result of plant tissue that has died from too much water. Kind of hard to say without more specific information.

How large is your container?

Is the Miracle Gro the moisture control type? Most growers find that it holds too much water for container tomatoes especially for SWC (Self Watering Container) growing.

Dig down with your finger about 3-4", is the growing medium wet, dry, or just right? If it is wet, don't water, if dry then water. If it is just right, check again the next day.
Mulching the top of your container with compost, straw, hay, rotted leaves, grass clippings, even shredded paper or sheets of paper or cardboard helps maintain a consistent moisture level.

Plants that are grown in any kind of container will need feeding more often than plants that are grown in the ground because each time they are watered, the water run off carries away vital nutrients. Many container growers will use a dilute solution of a liquid fertilizer as often as every week depending on the condition of the plant.

How often and how much are you feeding?

Betsy

It is NOT the Miracle Gro Moisture Control type, it's just the Miracle Grow Potting Mix. No water-retaining beads, but I'm sure the medium is massively wet (it's raining right now, LOL).

I'm feeding every week with Expert Gardener Tomato & Vegetable Plant Food (it's what my mom got me; 9-12-12). It's a granular fertilizer. What dilute solution of a liquid fertilizer should I be using, do you think, perhaps? I have also side-dressed with blood meal & used epsom salt to add nutrients.

I've used two tablespoons per plant as per the instructions on the food for feeding, so about four tablespoons have been added weekly.

I've attached another picture of some of the leaves.

Daren

I haven't seen any spider mites or pests on my plant, and since it has been raining so much, wouldn't they be knocked off? We're talking torrential rain.

The plot thickens!