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Jul 3, 2010 12:02 PM

Bottom of tomatoes turning brown

Tomatoes look great one day. Next day...bottoms have a nasty, spreading brown patch. Totally inedible.

What's up. Quick. The stuff is spreading!!!


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  1. probably blossom end rot.... looks ugly but does not harm the rest of the tomato. cut off and enjoy. the cause is not enough calcium, yes calcium, and magnesium. add crushed egg shells when planting and this will help. go to your local nursery and get a liquid supplement.

    3 Replies
    1. re: fmweekes

      An older lady here told me she puts (along with eggshells) a good double handful of dry milk in the holes when she plants. Then throughout the season she sprinkles dry milk regularly around the base of the plants. We tried it this year and we have a tomato jungle full of shiny green fruits.

      1. re: morwen

        Makes sense and what a great idea... natural, no chemicals; I am going to try that next year. I live in Edmonton Alberta and hope to be harvesting the first ripe romas next week.

      2. re: fmweekes

        Exactly! Egg shells have done the trick for me for decades. They so easy to collect if you cook eggs as part of your culinary regimen.

        Years ago my chiles also started to develop blossom end rot, and the use of crushed egg shells also ameliorated that problem.

      3. The leaves on the tomato plant or the blossom end of the tomato itself?

        If the former then possibly tomato late blight.

        If the blossom end of the tomato fruit is developing a black spot, then most probable cause blossom end rot, casued mostly by uneven watering:

        12 Replies
        1. re: junescook

          I would say late blight, I'm getting it for the second year in a row. Bottoms of more than half the tomatoes are brown, very sad. All you can do is dig the plants and the soil up, but do not send to the town dump or it will spread to everyone in town. I think you're supposed to burn the plants and then bury the ashes 3 feet deep, which I didn't do last year :-(
          Blossom end rot is black and moldy. That's usually caused by inconsistant watering IIRC.

          1. re: coll

            The ag agent here said burning is good enough, no need to bury. He also said putting the plant and all in a heavy duty garbage bag and trashing it is good enough if you can't burn or if there's a burn ban on (like there is here at the moment).

            1. re: coll

              Tomato late blight will cause the leaves of the plant to turn black from the bottom up:


              Blossom end rot produces a growing spot on the end of the fruit. It is the result of a lack of calcium but is cured by regular watering. There is normally enough calcium in the soil so regular deep watering will take care of the problem.


              1. re: junescook

                My local farmer looked at my half brown tomatoes and diagnosed, 300 years experience (family, not just himself) so I believe him. The leaves get a little messed up too though. I was hoping it was just blossom end rot but obviously not!

                1. re: coll

                  I spent a day working in the extension office this week. They have had a number of cases of lower leaf browning coming in and had a plant in a plastic bag for us to have for comparison. It was caused by a fungus called septoria. The coordinator said we should tell people that they could likely keep ahead of the infection by pulling off the infected leaves, putting them in trash bags and getting rid of them in the trash (do not compost). Also there were pamphlets to send out.


                  1. re: junescook

                    My leaves are fine, it's just the fruit.

                    1. re: coll

                      Here's an article that covers about all bases. What's troublesome about the blight diagnosis is that it generally attacks the plant (either tomato or potato) before the fruit.


                      1. re: junescook

                        This is a great reference, of diseases I've seen and not. I am saving for future, although I'm starting to think with all the local farms I'll just get my tomatoes from them, I'm just doing them up on the porch so "Bill Murray" (our local groundhog) doesn't get to them.

                        1. re: coll

                          We jad a cute little guy like that who lived under the shed in our back yard. The one day in the summer "he" emerges with 5 little ones. Fortunately, they pretty much kept their grazing to grass and clover and didn't bother our gardens.

                          1. re: junescook

                            That's what our does, we're the only people on the block with clover. It's like having a tiny goat!

                            1. re: junescook

                              Told my husband the story of the babies this morning, sounds like he would enjoy that. Guess we'll have to wait and see, maybe that's why she/he is eating so much.

                          2. re: junescook

                            Thank you for that incredible article. I have never seen anything more descriptive and written in layman's language. I will send this on to all my friends who grow their own tomatoes.
                            Once again, thank you for sharing.

              2. FWIW, I had quite a bit of blossom end rot on my tomatoes last year. I never really managed to fix the problem (tried the dried milk, fertilizer, more regular watering), but this year I managed to avoid it. Before planting, I mixed a good amount of compost into my potting soil (I'm gardening in containers right now). That seemed to hold the moisture better, and I didn't have any trouble. Just something to consider.

                1. so it looks like all my beefstakes are getting blossom end rot. They are still greenish--can I just let them ripen and cut off the bottoms? It just makes me sick that every year I have some malady--makes me not want to grow tomatoes.

                  2 Replies
                  1. re: sparkareno

                    Hi sparkareno. You can try doing that. This year, at least in the NE, is the opposite of last for tomatoes. They do not like temperatures over 90 any more than they like cold wet weather. To combat the BER, you have to give them regular, deep waterings. See the fact sheet below for some answers.


                    1. re: sparkareno

                      You can do that. It just depends on how ripe the individual tomatoes are. The BER will continue to spread while the tomato ripens but the part of the tomato not affected will still be good. BER is also confined to individual tomatoes so one hanging next to it won't be infected by another one or spread from plant to plant. We've been lucky so far finding only an occasional one on a near ripe tomato. In past years I've cut off the good part of the mater and stuck it in a baggie in the freezer. When I had enough tomato pieces I tossed them in sauces and casseroles. The ones that are still greenish can be saved by making fried green tomatoes or green tomato preserves.