Please read the FAQ about blossom end rot (BER).

Erratic watering is the problem.

http://faq.gardenweb.com/faq/tomato/ http://faq.gardenweb.com/faq/tomato/

Here is a link that might be useful: BER

As for the maggots...scoop out as many as you can and if some of the bone meal comes out too so much the better. Then buy some of the Mosquito Dunks (sold for standing water to kill mosquitoes), break them up and dissolve some chunks of them in your water used for watering the plants for several days in a row. If you don't get them all, no problem but get as many out as you can.

Next time, skip the bone meal since it doesn't help anyway.

Dave

Thank you both for the information. Erratic watering wasn't the issue, though. I was constantly checking that, and they never had a chance to get dry. I put the bone meal in because someone said there wasn't enough calcium; I hoped that would remedy that.

Dave, if I can't get all the maggots out, are my tomatoes a loss? Do I have to get rid of the plants? Are they somehow contaminated because of the flies? They DO have some nice new tomatoes on them

No the only threat is that the grubs will munch on the roots. But there are no food contamination issues.

As to the watering - over-watering is as much as issue as under-watering. Consistent slightly moist is the goal and that is almost impossible to accomplish in containers unless they are 30+ gallons in size.

Bone meal as a source of calcium, if indeed low calcium levels in the soil was the cause (which it isn't), takes many months to decompose to a form usable by the plants which is why it is a waste of time in containers. In ground gardens mix it in in the fall for effect the following year.

Dave