I had the same problem last year. This year, to combat the issue, I add a few tablespoon of liquid bloom 0.12.5 to a few weeks back and I do appear to be getting more tomatoes this year. The thing for me though is my piles are generally all leaves with me begging for green so I don't think it would be an excess of nitrogen. Good Luck...

Cabrita, yep, have a green house. I have nearly 150 plants for my sun-dried tomato business. In an average year, I get about 500-600 lbs that ripen on the vine. This year was anything but average with 27 degrees on June 11th and a hard frost on Labor Day. And 8000 green is not a typo (I am like anal so I counted them as I brought them in...) I have been drying them in my dehydrator since I brought them all in. My husband made 36 jars each of Marinara sauce, salsa and salsa verde (using tomatillos and green tomatoes.) For his green salsa, he slices and cooks the green tomatoes and tomatillos for about a half hour and then runs them through the food mill to remove the seeds and most of the juice (skins don't slip on green tomatoes.) Because he does this, his salsa verde is really thick and nice. Yes...northern gardening can be a real challenge. I have nearly 200 orchids indoors that give me something to do all winter. We bought a house on the Yucatan peninsula in Mexico and in 5 more years, we are retiring there. I CAN'T WAIT to be able to grow things year round.

Are you watering enough? As the plants grow bigger, sets fruit, and the days get hotter you might have to give them more water - when you water. Don't water more often just give them more water when you water. Also, do you do a deep watering once a week? Let the water come out slow so that it really soaks down deep. I heard it said once, "You cannot water too much when you water, but you can water too often". This has worked out very well for me. Since I started doing this about six ago BER has been a thing of the past. I know that BER has to do with calcium not getting to the fruit. Personally, I believe watering too often interferes with this process in some way. But I am no expert in that, perhaps someone who has a better understanding of the physiological processes could better explain it if I am off base here. It does help that I live in SoCal where we get so little rain. This helps me control when to water and how much water the plants get. When I deep water my plants I turn the water on just enough to keep a little pool of water in my water well. Just to the point that the soaking in does not cause the pool to get any larger or to disappear. I do this for about 20 min for each plant. Since it has gotten to be in the mid 90's and the plants are a lot bigger and putting on lots of fuit I am going to kick it up to 25min to 30 min one day a week. I water one other day during week, just not as deep. If you start this at the beginnig of the season you will help the plant develop deep roots, which is important for a couple of reasons. First deep water does not evaporate like it does in the top 4"-5" of the soil. Also, if the roots are shallow then they are subject to getting overheated by being too close to the surface. Tomatoes like their roots to be cool and moist. Both of these conditions are met if you can get the roots to go deep. Tomato plants can have roots as deep as 5' if there is enough moisture down deep. Roots go where the food and water is, so deep water often so the roots can go as deep as they want. Another thing, the roots of the tomato plant will extend nearly 18"-24" out from the stem. YOu have to provide enough volume for the water to be able to go both out and down. Finally, do you mulch? Mulch helps to keep the soil temp down. If your mulch is thick enough the top of the soil will be nice and cool. Mulch also helps the soil retain moisture. I have a 2" to 3" layer of grass clippings for my mulch. The layer is not so thick that it causes heat from composting and as the clippings decay they add nitrogen to the soil in the process. I learned that if I make the water well for each tomato plant about 30" in diameter this works very well. I put set the cages on bricks evenly spaced (about four) around the base so they are not sitting in the water. Each well is about 2" deep and I have the mulch inside the well. The mulch goes to about 3" from the stem. You want to try and keep the stem as dry as possible so don't pile up the mulch around the base. The mulch will retain moisture and if it is piled up around the stem it can cause fungal problems. But mulch does help keep rain and watering splash from hitting the bottom leaves, which is also helpfrull in preventing fungal problems. Try and water the plants at the base, not using an overhead sprinkler. This helps keep the leaves dry which helps control fungal problems. Water in the morning when the soil temp is at is lowest. Just some thoughts. Happy Gardening, Tom P.S. Yellowing leaves is normal to some extent. When plants begin to set fruit some bottom leaves will yellow. The yellowing (of a few leaves) is an indication that the plant is now setting fruit. Also, some leaves just yellow as the season progresses. You have to watch and make sure the yellowing does not seem to be greater that what you think should be happening. Don't ask me what "should" means, that is something you will learn as get more experience growing tomtoes. But, even though some leaves yellow the overall look of the plant should look healthy and new foliage is continuing to be added each day. As long as when you look at the plant it still looks green and not yellow. I would suggest you not pick all the suckers. The extra foliage will shade the tomatoes and help prevent sun scald. You will get a greater yield which will give you a reason to meet some of the neighbors that you might not have met yet, or you can become very popular at work or church. If the plant begins to get too tall for you, you can pick the suckers off the top leaders which will prevent it from growing any taller. Suckers will continue to grow at the lower parts which will continue to add shade for the Toms as they grow. There is a misconception that letting the suckers stay on the plant will somehow take energy away from the main stem. This is false. Each stem (this includes the suckers too) produces enough foliage to take care of all it's own needs for all the fruit it produces. None of the suckers steal anything from the original stem and fruit.

Although BER is a sign of calcium deficiency, it is often not a soil problem, but a watering problem. The plant does not get sustained calcium because of irregular watering. BER is also more common early in the season and is more common in pots because they may go through a wet-dry cycle. Plants in containers are usually fertilized with a liquid fertilizer The eggshells will take a long time to break down and release calcium. Yes, 3 plants in an 18 inch pot is a bit crowded. Tomatoes can grow roots from the stems. That is why they should be planted deep with about 1/3 of the stem going below the ground when you first plant them. It helps them develop a healthy root system. Don't put on too much nitrogen fertilizer or you'll get lots of leaves and not many tomatoes. When the plant sets fruit it is normal for the lower leaves to die off as the fruit ripens. Blossom end rot