Tomato bottom rot!

lovetotweet(7)July 9, 2009

Okay - I need some help here. My tomatoes were doing great, but I noticed that some of the green tomatoes had black spots of rot just on the bottom of the tomato - as they ripened, the spots just got bigger. So, now I've got a bunch of ripe tomatoes and all the bottoms are rotten! It seems to be happening across the board regardless of variety - though not to any of the cherry/grape tomatoes. I'm confused - I don't see any bugs and up until recently the plants have looked good... I'm having issues with blight now, but, honestly my area has been so blasted humid I'm surprised anything is doing well.

So - any ideas? I tried spraying with neem; I've used the dirt doctor's plant wash, but can't seem to get a handle on it.

Oh, and the same thing is happening to some of the peppers...



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Without seeing pictures I would say BER (blossom end rot). That is what it sounds like. There are many ideas on treatment and prevative measures. I have found in my garden that paste types are the worst to get it and usually after the first fruit set I have no more trouble. I'm sur Dawn and others will come along with some more suggestions. I could name all I've heard and a few I've tried. In the end I've usually decided that time helped as much as anything. Weather conditions and heavy rain can contribute to this condition also in my opinion. Jay

    Bookmark   July 9, 2009 at 2:11PM
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It certainly sounds like blossom end rot to me also and is not uncommon in your earliest tomatoes. There are several schools of thought on this including lack of calcium, but I think it is caused by uneven watering and a young plants inability to get the nutrients it needs from the soil. It seems that even when your soil is adequate, a young plant has difficulty getting everything it needs as a young plant to produce it's first fruits.

If you had lots of rain, then alternating bouts of hot weather that would also contribute. My guess would be that it will straighten out on it's own after these first few fruits. If you see a tom with BER, pull the fruit. You may be able to use the good parts of the fruit if you use it right away, but it will rot quickly.

BER and fruit worm damage always seem to come at the very worst time when you are anxious for that first bacon and tomato sandwich of the year. LOL

Dawn will probably have some ideas of dealing with it.

    Bookmark   July 9, 2009 at 2:34PM
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Okiedawn OK Zone 7


I agree with Jay and Carol that it sounds like Blossom End Rot, which is a very common tomato disorder. Note that it is a disorder, most likely linked to environmental factors, and it is not a disease and it is not contagious. (In a bad year it can seem like it is contagious though.)

As Jay and Carol both noted, BER is most commonly seen on some of the first fruit set by a plant, though not necessarily on all the early fruit.

For a long time, it was widely believed that a lack of calcium caused BER or at least contributed to it. For that reason, it was believed that if you added a source of calcium to your soil, you'd solve your problem. Honestly, though, it is more complicated than that and you can add loads of calcium to your soil and still have BER.

The more current line of thinking is that BER is a symptom of stress, and it is specifically related to a couple of factors: (Jay, if I forget something, please add it.)

1) It tends to happen earlier as opposed to later, and often it happens as plants are ripening their first heavy load of fruit. Sometimes I've had the earliest fruit or two ripen but then had BER show up on the next round of fruit that set. It is most commonly seen on green fruit as they start to enlarge and on large green fruit as they start to ripen.

2) It tends to happen during periods of environmental stress which could include variations in temperature from normal to very hot OR variations in moisture from very wet to very dry to very wet again, OR both temperature variations and moisture variations in combination. One reason it is more commonly seen on container-grown tomatoes is that it is much easier to let container-grown tomatoes get too dry....and then, of course, you water them heavily to make up for letting them get too dry.

3) It tends to happen quite often when the plants seem deceptively green and healthy and are carrying heavy loads of fruit. Remember, though, that a heavy fruit load in and of itself stresses a plant which just makes the scenario more complicated. Some people feel BER is commonly seen on overfertilized plants that look "too healthy" and there may be some truth to that too. Overfertilization would contribute to BER by causing very rapid (in fact, abnormally rapid) plant growth which can stress a plant.

4) Tomato plants need calcium. Tomato fruits need calcium. It is believed that when stress hits a plant, the plant (through processes which we don't really understand) can "pull back" the calcium from the fruit in order to use the calcium itself. Or, perhaps the fruits voluntarily "surrender" the calcium back to the plant. Either way, the calcium is in the plant but not in the fruit and that is when your BER shows up....during that period that the calcium distribution within the plant/fruit was uneven. So, you see BER is partly a result of anything that stresses the plant (like uneven temperatures or uneven watering or overfertilization) plus the plant's inner mechanism for using calcium. Thus, there really isn't a quick fix.

When I have Blossom End Rot, I take a multi-pronged approach. First, I check every fruit on the plant and pull off all the ones that show BER. Then I try to analyze what I might have done to contribute to it. If I think I've been doing anything "wrong", I try to correct it. If the plants have been too dry, I try to be more consistent about watering them. (This is especially important in container-grown plants.) If the plants are not heavily mulched, I add more mulch. If they are looking hungry, which often manifests itself in poor leaf color or growth, etc., then I feed them.

Some people believe you can dissolve some hydrated lime in water and water the plants and it will help. Some believe a water/milk mixture does the same thing. I'm not sure if either helps, but normally they don't hurt. For a long time (and perhaps even now), you could buy sprays to spray on the fruit. They contained calcium and it was believed that spraying the fruit would stop the BER. Research has shown, though, that tomatoes do not absorb calcium through their skin, so I wouldn't waste my money on the sprays.

I always put a handful of bone meal in each planting hole when I set out my tomatoes, although I am not sure if that makes a difference. I also use Tomato-tone plant food which contains calcium. I put a handful in each hole at planting time and sidedress the plants with it monthly.

I think most tomato plants do 'outgrow' BER once the plants are large enough and strong enough that they can handle environmental stresses + the stress of a heavy fruit load.

BER is very common on most types of paste tomatoes, very rare on cherry/currant/grape-sized tomatoes, and is found in varying amounts on most other tomatoes. There are some varieties that seem to get it pretty regularly, while there are others that seldom get it.

I almost never get BER on plants grown in the ground, but sometimes see it on plants in containers.

For what it is worth, there are a lot of people seeing a lot of BER this year, and I think that can be attributed to the spring/summer weather which have had a lot of moisture and a lot of heat early, both of which stressed the plants.

Once you remove all the affected fruit, feed with the fertilizer of your choice if you think the plants need it but be careful not to overfeed. Mulch well if you haven't already because that helps keep soil moisture levels and temperatures more stable.

You mentioned blight on the foliage and that also is incredibly widespead this year. I think internet "talk" about blight is the highest this year that I can remember, and I know from seeing plants around us (including our own), that it is common here in our part of OK this year.

Hope this info helps.


Here is a link that might be useful: Previous BER Discussion

    Bookmark   July 9, 2009 at 4:23PM
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Thank you everyone! That sounds exactly like it -and it is on the earliest ripening fruit. They've received consistent watering and are in raised beds - applied lots of organic amendments to the soil, mulched well, and fed with various recommended tomato food, etc. It's certainly possible that I'm doing something wrong, but I'd bet that it's weather related. And, they were stressed going in since our beds were not prepared before we had all the rain here in central OK, and then we couldn't plant because the ground was too wet...and then it immediately got hot, LOL! So, I'm guessing that's what is up, but I will follow your advice and see what happens! Thank you!!


    Bookmark   July 9, 2009 at 5:05PM
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sammy zone 7 Tulsa

I appreciate your responses to this thread, but I am bringing it up again to see if there are dynamics this year that would cause it.

I just removed 4 tomatoes from Jet Star and one from Black Krim.

Last year was my first year to grow tomatoes, and they are in 20 inch pots. There are 20 of them. I was in the habit of watering them about every couple of days, but spraying them with water once or twice a day. My roses seem to like that when it is very hot, so I sprayed the tomatoes too.

This year I have watered about every 2 or 3 days. Before I think about water, since they are in pots, I need to fertilize them.

Did one of you say that they do not absorb fertilizer through the leaves, or water? As it gets hot, do you think it is harmful to spray them, and water them a little bit daily?

How do you water? What I do may not be relevant. I would like to know how to water in containers that are in the sun.


    Bookmark   June 2, 2010 at 12:44PM
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Okiedawn OK Zone 7


I did say that tomato fruit cannot absorb calcium through their skin so spraying the fruit with a milk/water mixture doesn't 'fix' BER. I didn't address whether tomato foliage absorbs water or nutrients (I believe it does).

I have mixed feelings about spraying water on the leaves of the tomato plants. If your ground around the pots is well mulched, and there is mulch on top of the soil in the pots, then spraying water on the foliage likely will not hurt and probably will help as long as the tomato foliage is disease-free. However, once you have any bacterial or fungal diseases showing up, I'd avoid putting water on the leaves because it can splash and transport fungal spores or bacteria from one plant to another or from unhealthy foliage on a plant to healthy foliage on that same plant.

With plants in pots, I do not water on a daily schedule but on an as-needed schedule. I stick my finger down 2-4" into the soil...just as deep as I can stick it....and if the soil is dry, I water. Depending on the temperature and the amount of wind, I may water once a day, twice or day, or if temps are above 105 and it is windy, as often as three times a day. Smaller pots need water more often than the really large ones, but even the molasses tubs, which are the same size as a whiskey half-barrel, need daily watering nost of the time during the summer months.

Feeding plants in a container is harder and I don't think I've got it down to a science yet even though I've grown tomatoes in pots for quite a few years now. I try to put a lot of compost, manure, blood meal, bone meal and other good stuff, including Espoma Tomato-Tone, into my soil mix when I blend it and fill the pots. However, all those organic amendments/fertilizers tend to be slow release, and heavy watering can leach nutrients out of the soil, so I also feed the plants at least once a week with a water soluable plant food. I prefer to use compost tea or liquid fish or liquid sea weed, but occasionally I'll use Miracle Grow if I am watering very often and the plant seems hungry.

With plants in containers, it can be quite a challenge to keep them evenly moist all the time. Some years I've used a drip irrigation kit set up on a timer, but that works best if all the pots are the same size. If you have pots of different sizes, you have to put more emitters in the larger pots to ensure they get enough water, for example, so you may have to tinker with a drip irrigation system if you have pots of varying sizes.

Blossom End Rot probably will be a big problem this month because the heavy May rains in many areas were followed by the onset of sudden heat. In addition, many plants have been hard hit by high winds or hail so they're stressed from that too. Temperatures this weekend will be as much as 10-15 degrees above average for this early in June, and some of us in southern and western parts of the state had have temps about 10 degrees above average for a couple of weeks now. All these stresses tend to combine to make BER more of a problem than it otherwise would be.


    Bookmark   June 2, 2010 at 1:34PM
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Sammy, I am anxious to see Dawn's response, too, altho I have not seen any BER on my Jet Star or Rutgers, which are the main producers right now, as of yet.

It seems like there is a certain balance to be sought in relationship to watering and fertilizing working in conjunction with Mother Nature - the heat that has now set in, rain, etc. I am just going to have to "play" with everything for awhile until I hopefully get it right.

My tomatos are grown in containers, too, and from this thread, it seems like they are the most susceptible because of the issues that have been mentioned. So far, I usually feel the soil down about 3" to see if they are dry, and if so, I water them.

I use Tomato Tone fertilizer by Espoma, which has a lot of different micro nutrients including Calcium and Magnesium. But I am trying to be careful not to overfertilize. So far, I am applying about once a month.


    Bookmark   June 2, 2010 at 1:38PM
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I discovered BER on 1 Jet Star and 2 Rutgers today. It is on the second set of tomato that developed, and so far, the first ones seem to be okay, altho not ripe yet. I tossed the bad ones.

I repotted the Jet Star into a 25-30 gal. container, and it was pretty rootbound and dry. So, it had been drying out quicker than I thought. If your containers are small enuff, i.e. the 5-gal. it might be a good idea to check them the day after watering to see how they are doing as far as your watering habits. It wasn't difficult to remove the plant from the container, just a sharp tap on the bumper of the car, and it slid right out. I wish I had done that earlier, but it didn't cross my mind.

Rutgers is staying in its 5-gal. container, and I'll just have to step up watering on it. It is no longer showing signs of blooming, so it may be done producing. There are quite a few clusters of 3 or 4 tomatos on it.

That is the only thing I can think of to change right now. I think it is environmental and watering in this case. Got too hot, too fast, and I wasn't keeping up well with the watering needs. You live, you learn, so I'm not going to cry about it, and hopefully the plants will straighten themselves out soon.


    Bookmark   June 4, 2010 at 11:34AM
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