Looks like blossom end rot. I had this problem before when growing tomatoes in pots. Its usually from a calcium deficiency or inconsistent watering.

Tomato plants have a extensive root system and even though your pots are 18 gallon I would probably only have one plant per pot. Too many plants = too many roots = drying out fast even with self water pots so your issue is probably from over crowding.

If the rot on the bottom is dry like a scab you could leave them on the plant (or pick) and they should still ripen - just cut off the bottom when you eat it. You'll know soon enough if still good inside.

I would suggest removing two plants from each pot (and as many of their roots as possible) and add some fresh soil to fill on the holes. Try it on one or two pots to see if it makes a difference.

I don't think the issue is overcrowding. All the plants have grown to be quite large (to the top of 4' fencing around the container). So large I had to trim them quite a bit to keep them manageable (removed most of the suckers and a few lower branches). Like I said I am pretty sure I have it narrowed down to a lack of water as the issue appeared as soon as the extreme heat started this week and the top of the soil dried out because I didn't add wood chips to it. I did not see any signs of problems whatsoever until the heat hit a couple days ago. Where I live we don't get too many hot days like this so I don't see the heat being an ongoing issue.

Ideally I would like to have them each in a separate 5 gallon bucket but my budget doesn't allow for that right now. Considering the romas were one of the smaller tomato plants I'm growing I used my 5 gallon buckets for other varieties and put the romas in 18 gallon containers. Believe it or not I have a few brandywines in 5 gallon buckets (did that before I knew how big those plants get). They were 1'' tall seedlings about 3 weeks ago. Right now most of them are almost 5' tall with flowers and some have a couple tomatoes. Those plants I do plan on eventually moving to a bigger container because I know they can get quite large from some pictures I have seen.

My cherry and other varieties of tomatoes are doing great in 5 gallon buckets and are already producing ripe tomatoes. I even have a black tomato plant I'm experimenting with that appears to be doing good. I have plenty of 5 gallon buckets to put my plants in but the cost of the soil I'm using is limiting what I can do right now. Once the greenhouse is going I might have more money to work with and will probably go with bigger containers but for now I am using what has been given to me for free (and the least amount of soil per plant I can get away with).

What I need to figure out now is if my romas will keep producing after I pull the rotted ones off or should I start over from the clippings I have. From what I have read romas are considered determinate but might produce a second cycle of tomatoes in some cases. Correct me if I'm wrong. A friend of mine told me pull the bad tomatoes and put the plants in the shade for a few days (nice thing about container gardening) so I think I will try that before I do anything else.

Well despite all the evidence and experiene to the contrary it sounds as if your mind is made up to stick with your methods. So I'm not sure how helpful any of us can be other than to say yes, your plants will grow some additional fruit. Whether or not they will also develop BER all depends on if you are willing to changes some of your methods.

Thirsty Dirt gave you some good advice above and you'll find few growers who wouldn't agree that your plants are way over-crowded. Not to mention the issues that will develop with your 5 gallon containers as time passes and the plants age. Any plant will start out well in even a 1 gallon pot but that doesn't mean it will continue to do well. So I wish you luck.

There is some truth to the old adage that 'less is often more". Less containers but bigger containers and in this case, less plants. Not only does it mean more water per plant at a consistent level it also means more healthy fruit.

There is a great deal of very applicable information available to you over on the Container Gardening forum here.

Dave

This is also my first year of gardening so much of what I can say is based on research and some experiences I have had so far this year.

I, too, am using containers (Smart Pots) to grow tomatoes. There seems to be some debate on whether you can put more than one plant per pot or not. However, Smart Pot officially recommends using a 20-gallon plant for ONE indeterminate tomato plant. My experience so far has said, this is a good idea as beefsteaks and romas are deep rooted and somewhat greedy regarding water and nutrients.

What I have also found is that one plant per pot along with a companion plant (such as basil) is a great way to go.

That being said, you seem married to the idea of more than one plant per pot. Most research on blossom end rot (BER) is based on a calcium deficiency along with two other possibilities - using the wrong type of nitrogen source and/or excessive nitrogen & wide moisture fluctuations. I've linked the simple article from Ohio State for you to read. It helps narrow down the reasons for BER in an easy to read and follow manner.

Someone very wise on here made a good point that container plants need more frequent & regular applications of fertilizer along with water unlike plants in the ground. With three plants to one 18-gallon pot, have you upped the nutrient/fertilizer rates for your plants? Since you are asking the plants to split whatever nutrient you feed the pot three-ways, it only stands to reason that either all will split the difference (and all will fruit and grow modestly) or play survivor of the fittest.

Since you can't really use the BER fruit, it might seem prudent to trim it, up your fertilizer and watering routine and hope for the best for the next set of fruit.

Also, are you sure that your Romas are determinates?

Here is a link that might be useful: Blossom End Rot for Tomatoes, Peppers and Eggplants

Let me put my $.02 in the pot:

BAD NEWS: you could not and cannot do anything about it.

GODD NEWS: hang around a bit longer, it will go away.

BER is not a DISEASE caused by bacteria, fungi, virus, ... It is a physiological disorder.
Luckily, it does not happen to ALL tomatoes and to those that happens, does not(usually)last all season long, bt only in the beginning when the plant is (relatively)smaller...
(I owe most of this info to Dr. Carolyn)

Funniest CURE that I have heard SO FAR is feeding the plant crushed egg shell. It is like putting aspirin on your forehead to get rid of your headache. Feeding TUMS, anti acid tablets I, s not as funny.

There seems to be a misconception here that I am closed minded and set in my ways. That couldn't be further from the truth. In fact my garden right now is pretty much an experiment to see what works and what doesn't. Considering that I am unemployed and have a limited budget for gardening supplies I am trying to save as much money as I can so I can invest in good soil. I know 5 gallon buckets might not be ideal for some plants but I have basically an unlimited free supply of them so that is what I am using right now. If I get half as much tomatoes as the plant normally produces it is better than no tomatoes.

That being said there are a few reasons I came to the conclusion my end rot problem was due to a watering issue and not over crowding. First of all the roma plants have been healthy and showing new growth everyday for at least a month. Then a heat wave hits at the beginning of this week. That is when the problems started all of a sudden. I did not get around to putting wood chips in the containers for the romas and the soil dried out on top. By putting 2 and 2 together most people would come to the logical conclusion that the end rot is being caused by lack of water.

Not to say that there isn't going to be issues in the future due to over crowding there very well could be. Like I said it is sort of an experiment right now. Some experienced gardeners have told me I could get away with 3 plants. Some people have told me it's too many. I guess I will have to just find out for myself. I have about 20 healthy cuttings from the romas I have propagated so I have a backup plan in case things go wrong. As I said earlier I will have access to a decent sized heated greenhouse for the fall and winter so this is basically a trial run for what I'm going to be doing in the greenhouse.

I have been adding worm castings to most of my plants every couple weeks. I just got an aerator yesterday and I'm going to make some worm casting tea and try that. Does anyone know how much castings I should use for 5 gallons of water or any websites that might have more info about that?

I pulled about 15 rotted tomatoes from the plants last night of various sizes (none full sized). I ended up cooking them under the broiler and cutting the rotted part off then put them in salsa. It turned out pretty good. I am probably going to have about 10-15 more to pull off today. Some of them with very minor rot I am going to leave on and see how they do. I will keep you all updated on what happens here.

I agree that you have probably overcrowded your tomatoes for optimal growth and production, but tomatoes are adaptable and I have seen them produce fruit in conditions that boggle the mind. (Think 4" pot, with no feeding & inconsistent watering. That poor mistreated plant put out two tomatoes less than 1" in diameter. No, I don't know what the variety was. I told the grower I was going to turn them in to the SPCP and the SPCT!)

BER (Blossom End Rot) is not usually a result of a lack of calcium in the soil or growing medium, but rather a transport issue. Rapidly growing plants/fruit can't transfer enough calcium to the end of the fruits and BER raises its less than pretty head. However.....

Because your plants are in containers, there could be a deficiency of calcium in the growing medium. You can use either dolomitic (garden) lime or gypsum to treat the deficiency. The suggested amount is rate of 1 tbsp/gallon of soil, or 1/2 cup per cu ft when you are preparing the containers. I can't begin to guess how much to use as a top dressing, you may want to ask about it over in the container forum.

I hope that helps.

Betsy

Here is a link that might be useful: Container Gardening Forum

I notice my next door neighbor with his fifteen container tomatoes. He was watering the top part of the plant which allowed faster spreading of wilts and blights.

The other thing was his watering method. He asked why small roots were growing at the top of his container. I suggested he water each pot slowly, until water came out from the bottom holes. The roots might have grown up rather than down if no water was reaching the lower potting media.

The latest info I've read suggested that calcium is not as important for BER as once thought. Watering patterns may be the most important.

The amount of worm castings you use really depends on the "recipe" you use to make compost tea.

I've seen recipes with as little as 1/2 cup to 2 cups. I have about 8 different recipes tucked into my Evernote notebook. If you list what you plan to put in your tea based on ingredients you have on hand, I can find the correct proportions per any given recipe. Just let me know.

Just FYI, I've learned that gardening has a ton of variables so you have to find what works for you. Guidelines are just that - guidelines not cut and dried rules.

Glad to hear you were able to salvage the damaged fruit.

My plants are watered from the bottom through a wicking system I built into each bucket. So basically the plant shouldn't get over or under watered because it takes only the water it needs. However with my roma tomato containers I did not put wood chips on top of the soil like I did with my other plants so the water evaporated through the top and the soil started to dry out. This system works great for my other plants. I add water to the bottom of the container as needed and the plant does the rest.

Just went out and looked at my plants. They all have new tomatoes on the top of them that weren't there last night. The leaves are not quite as wilted and I think they are starting to come back. I pulled about 10 more smaller rotted tomatoes off and plan on trimming some dead leaves off later. The weather has cooled down a bit and we might even get some rain here finally (then I can fill my rain barrels again). I think there might be some hope of getting some ripe tomatoes off these plants if I keep up on my watering.