I'm growing a hybrid, determinate, health kick variety. In the last couple of weeks, several black spots started to appear in leaves, many leaves started to turn yellow and many of the flowers fall off. Not sure what can be the problem. Uploaded some pictures to see if someone can help me identify the issue:
Looks like Early Blight. In cool, moist conditions Blight spreads from the soil to the leaves and then infects the rest of the plant.
If you have plenty of other tomato plants I would recommend disposing of this plant ASAP.
If you want to try to save it: remove any affected leaves and fruit and any other leaves close to the ground. When watering gently pour the water around the base of the plant and avoid splashing any water on the stem or leaves. Don't spray the plant with water. In fact the best way to water is to put a tray under the pot and fill the tray with water so it soaks up water into the base of the pot. Try to bring the plant in from the rain when necessary.
Try to keep the plant warm by keeping it in the sun.
Isolate the plant from any other plants you may have.
Give it a week or two to see how things are going. You probably won't totally get rid of the Blight, but you can control it. If it doesn't get better you might want to try a copper fungicide but that will effect your ability to harvest and consume the tomatoes. Read and follow the directions on the bottle.
You can spread blight from plant to plant via tools and your hands. Clean your hands and tools before handling any other plants. A good practice is to use a separate set of tools for any infected plants. Handle this plant last, tend to your other plants first.
Once your are done with the plant dispose of it in the garbage, don't compost it. Also throw away the dirt. Wash out the pot with a bleach solution and let it dry thoroughly before storing. You may want to avoid using the pot next year.
