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Blossom End Rot

Newnan, GA(Zone 8a)

okay, what's the answer? we had tons of rain for a couple of weeks, could that be it? These are all in containers and the plants are gorgeous, but every tomato that has turned has it, except for the cherry types. HELP!

Allen Park, MI(Zone 6a)

Try sprinkling some powdered milk around the base of each plant.
Its supposed to add calicum to the plant.
I haven't tried it yet (haven't had BER since I heard about it) but several people said it works.
Let me know.


Salem, NY(Zone 4b)


Bolssom end rot has many causes. But the good news is that it ususally goes away as the plants mature and can better handle the many stresses that can induce it. It used to be thought that BER was due to a lack of calcium but research has shown that plants with BER fruits have plenty of calcium.

Here's a post I wrote about BER and perhaps it will help explian some of the issues:

Subj: BER
Date: 01/27/2002 10:38:29 AM Eastern Standard Time
From: Cmale
To: Cmale

From: cmale
Date: Fri Jul 27, 2001 3:08 pm
Subject: Blossom End Rot

Subj: Re:Blossom End Rot
Date: 97-05-26 20:28:45 EDT
From: Cmale

Blossom End Rot (BER) is one of the most common tomato problems seen in the early part of the season. It is a physiological condition, not a disease caused by a fungus or a bacterium or a virus. Therefore it cannot be treated.

And as I'll explain below, it is very difficult, if not impossible, to
prevent. BER has nothing to do with the blossoms, it refers to the fact that at the end of the tomato opposite the place where the tomato is attached to the stem, called the stem end, is the bottom of the tomato, which is called the blossom end. You often can see remnants of the blossom attached to that end as the tomato forms. At the blossom end one sees a flattened area that looks
leathery and initially brown and then black, as the fruit rots.

BER is said to occur when there is uneven watering, drought, heavy rainfall, excessive nitrogen fertilization, rapid plant growth or root pruning during cultivation, high winds and rapid temperature changes. So lots of conditions have been associated with BER. But the rapid plant growth and nitrogen fertilization are both common to conditions seen early in the season, and indeed, that is when most BER occurs. Then it usually just goes away.

BER occurs because under the conditions just stated, Ca++ moves from the fruit into the vasculature (stems) of the plant. Or, some feel that Ca++ never reaches the fruits becasue under stress demand for Ca++ exceeds supply.This lowered amount of Ca++ is what causes BER. Excessive rates of transpiration (kind of like sweating in humans) also is involved in Ca++ displacement. Thus, the plant as a whole is NOT Ca++ deficient, the Ca++ has just been displaced.

Many books and magazine articles tell you that by adding Ca++ in the form of lime or eggshells, for instance, that you can prevent BER. That does NOT appear to be true. It was several years ago that I found out that University field trial experiments have so far failed to show that BER can be prevented by addition
of Ca++. I recently e-mailed my friend at Cornell who told me all this two years ago, to again confirm that it was still true, and will update you, if necessary. Peppers and many cole crops are also susceptible to BER and there's quite a bit of literature on BER and Ca++ for those crops also. The results are the same; addition of Ca++ does not prevent BER.

Some data strongly suggests that foliar spraying with Ca++ is of no use because not enough gets to the fruits to do any good. And it's known that the sprays for fruits that are sold are usless. No molecules can get across the fruit epidermis. If they did, just what do you think would happen to the fruits when it rained.LOL

Not all varieties of tomatoes get BER. Some never do, others are horrible. That's not surprising since certainly there are slight physiological differences between varieties. After all, almost all garden tomatoes, with the exception of the currant tomatoes are in the same genus and species, Lycopersicon lycopersicum. And we humans are all in the same species, Homo sapiens, var. sapiens....and look how different some of our physiologies are.

So, BER is a physiological condition, cannot be cured, and current
literature data suggests it cannot be prevented. It occurs on some, but not all varieties of tomatoes, is usually seen early in the season and then stops, for most folks. It would be nice to say that you could even out your watering, prevent droughts and heavy rainfalls, ensure even and not rapid growth of plants and not disturb the roots by shallow cultivating. But on a practical basis, I think we all know that's almost impossible. So, BER has never bothered me, I just ignore it, and it goes away with time.

Adding Ca++ to soils that are Ca++ deficient makes sense, but few soils are. And if soils are acidic, Ca++ is not taken up well but addition of Epsom Salts to the soil can aid in Ca++ uptake in such acidic soils.

Many folks add Ca++ and then see that BER disappears. What they fail to realize is that BER is going to go away anyway, as the season progresses. And that's becasue as the plants get larger they are better able to handle the many stresses that can induce it. So one cannot correlate addition of Ca++ to disappearance of BER. Universities have done so many stidies on this already
becasue BER is a billion dollar problem in the commercial veggie industry.

Of all the stresses that can induce BER thetwo that are most under control of the home gardener are fertilization and water delivery.

That is, too much fertilizer causes plants to grow too rapidly and is perhaps one of the major causes of BER developing. Too rich soils do the same thing. Plant growth simply outstrips the ability of Ca++ to get to the fruits.

Mulching to help ensure even delivery of water also can be done and is also one of the two major causes, IMHO, of BER.

BER appears usually on half ripe fruits but also can appear on grass green ones.Lack of Ca++ only occurs at the blossom end of the fruit and it causes tissue destruction which leads to that papery greyish/blackish lesion appearing.Now sometimes that lesion opens up and fungi and bacteria enter and that causes the rotting and also the appearance of fungal growth on and in the lesion.

Just pick off any BER fruits that appear and soon the next fruits to ripen will BERless.

Many books, magazine articles and websites still say to add Ca++ as lime, eggshells, etc, and seem not to be aware of all the research that has been done in the last 20 years. But many books, magazine articles, are now sharing this newer information about addition of Ca++ not being able to either prevent or cure BER except in rare situations of low Ca++ soils or acidic soils.

I suppose it will take another generation for the right information to be present everywhere. And from my own experience i can tell you that there will be folks who will get madder than can be when they read this kind of info becasue they simply believe otherwise. So be it. LOL Addition of modest amounts of Ca++ aren' t harmful, but I feel strongly that folks should know what's going on with past and current rsearch re BER and Ca++.

Hope the above helps.

NY, zone 4/5
The above updated on 7/27/01

Efland, NC(Zone 7a)

Thanks Carolyn, lots of great info~
>And if soils are acidic, Ca++ is not taken up well but addition of Epsom Salts to the soil can aid in Ca++ uptake in such acidic soils<.
I know Epsom Salts are magnesium sulfate, not calcium. Is this a case where the plants need the magnesium in order to utilize whatever amount of calcium there is? Or does the Ep Salts play a role in changing the pH of the soil so the plant can grab ahold of the then-available calcium?

(As an aside, I know plants need magnesium in order to produce seed/fruit etc (or so I read once). Wonder if Epsom Salts really aids in helping "stubborn" plants to set fruit. It seems to me it has helped me in the past (and certainly will green up the plants!) but wonder if that too was just a condition of the end result happening in due time whether the got sprayed or not.)

Richmond, KY(Zone 6b)

re: epsom salts. I'd always been taught that the amount of magnesium needed is so small that virtually all soils have enough of it. Adding epsom salts doesn't supply magnesium, but rather helps release calcium so that plants can use it.

Is this correct or just a coincidence? Beats me. But the only time I had blossom end rot was the one year that I didn't add epsom salts when I transplanted.

I'm sure, as Carolyn suggests, that there are a whole lot of things involved in the dynamics of plant nutrition, many of which we aren't even sure of. So we have to just be pragmatic, many times, and do what appears to work.

I figure if adding epsom salts doesn't do any harm (and, apparently, it doesn't), and might help, then it makes sense to do it.

Efland, NC(Zone 7a)

Good point Brook. Was also wondering since E Salts is magnesium SULPHATE then maybe the sulpher also contributes...maybe that is why some folks put a matchbook in each mater hole. SO MUCH to consider here! (I love it!)

Salem, NY(Zone 4b)


Addition of Epsom Salts to acidic soils apparently raises the pH enough to allow for Ca++ uptake from what I've read. I can't discount that in some other way it might aid in Ca++ uptake but I haven't read about it.

As regards Mg++, I agree with Brook that there's plenty in the soil. So many times folks say it has to be added because it's necessary for photosynthesis.

Two points to be made there. First, look around you at the green trees, shrubs, veggies, flowers, etc, and ask your self if someone is running around adding Mg++ to the forests, plains, and all else on earth. (smile)

There is but one Mg++/molecule of chlorophyll so the amount of Mg++ needed is something in the picogram range, which is 10 to the minus 12 or so. Plenty of natural Mg++ in most places most of the time.

The form of sulfur found on matchheads is not usable from what I know. Somewhere in my faves list ( of unfortunately over 800 items) I have a link on that but you'd have to shoot me in the foot to force me to go thru that tonight to find that link.

Carolyn, where it was 41 F this AM and going down to the same or a bit lower tonight. That's on the other side of Egg Mt from Manchester, VT where we set a record low last night.

Richmond, KY(Zone 6b)

Shoe: I add matches when I transplant, but for the phosphorous, not the sulfur.

Here, again, I don't know if it really helps. But it don't hurt. And I get the matches for free at restaurants, so I'm not out anything.

Efland, NC(Zone 7a)

Okay...thanks folks! Good info on this thread! I'll try to make sure some of it stays in my brain!
(Carolyn, how in the world do you manage so many tomato plants with that cool temp? Hope this is a rare season and not the norm there.)

Salem, NY(Zone 4b)


These few nights of low temps are highly unusual here and as long as the temps stay above 35, God forbid, barring any weird microclimates, all is well.

On average, 18/20 years here where I live are a normal zone 5a to b, the other two years perhaps a zone 4b.


(Zone 6a)

Has anyone noticed that cucumber vines will smother and ruin beautiful tomato vines?? And I thought they were supposed to be compatible. WRONG!!


Spring Hill, FL(Zone 9a)

use of Dolomitic lime has proven to prevent BER in my garden. I apply it once each year on or about July 4th. Dolomites supply both calcium and magnesium but whatever, before I used it I had horrific problems with BER and now have none growing the same varieties of tomatos. And this only 40 miles from Cornell U.!!

Ivinghoe Beds, United Kingdom(Zone 8a)


I can't add much to this erudite debate except to say...

YES! I got blossom end rot when I grew tomatoes in pots, using normal purchased compost.

NO! I haven't had it for three years BECAUSE I mixed into the base my own proprietary mix of:

powdered eggshells
powdered dried comfrey

One third part of each.

I dried my eggshells by putting them in a microwave for four minutes at full power, then smashing them into a jar. I used a coffee blender to powder those dried comfrey leaves. And I bought the kelp at a wholefood store.

And I mixed them all in a tub. And then I put, and mixed in, a big handful of this mix at the base of each tomato module when I set it in the pot.

Result: the tomato gets calcium plus potash plus trace nutrients. And it costs zilch!


Newnan, GA(Zone 8a)

John, don't leave yet. I think this is clearing up, but since I can't get to the bottom of the pot now, can I add these to the top and water in??

Ivinghoe Beds, United Kingdom(Zone 8a)

Yes, of course, you can!

But it would take time to circulate down from the roots. Better idea is to water the tomatoes with comfrey tea (or other potash-rich mix) mixed with a very little lime or wood ash.

'Twil do the same job, bringing calcium to the roots, faster.

Newnan, GA(Zone 8a)

ummm.....I have a bag of muriate of potash, can I use that in any way??

Ivinghoe Beds, United Kingdom(Zone 8a)

Ugh, sounds very chemical to me.

Better to use wood ash or powdered eggshells, methinks.

Sierra Foothills, CA(Zone 8a)

Ok, folks! Since I planted my 'maters so late this year, Jun 15th, the tomatoes are still green. Usually when I plant them early the nights are around 45-50 degrees. Now the nights stay no lower that 55-60, so even though the days are in the nineties the plants have set fruit. The Early Girl has already about 15 small green ones and loads more flowers. The Brandywines are just starting to set fruit, and the plants are 3' tall already.

I think I will go and make up a mixture of milk, epsom salts, and some wood ash and apply it to only one of the Brandywines, then see what happens. Whadyaa think??

(Zone 6a)

I think that would be a good experiment.....and also think you will see no difference in the two plants:)


Sierra Foothills, CA(Zone 8a)

You are probably right, Owen. When I planted them, I used a soil mix including dolomite lime, jersey greendsand, rock phosphate, crushed and dried eggshells, manure, compost and peat moss. So far, these are the best looking tomatoes I have ever grown. They are in a raised bed with hardware cloth on the bottom so the gophers won't come in. My neighbor said that this would not work 'cause they ate the roots that went down through the hardware cloth. HMMM.

So IF the gophers don't eat them, and they raccoons don't get in, I'll be watching for blossom end rot. Always something, huh?

(Zone 6a)

LOL. I don't have gophers, but I do have thousands of slimy slugs that just love to eat anything except weeds:)

Sounds like you put the right stuff in the soil....just talk to the tomato vines and caress them and tell them how nice they are and etc.


Sierra Foothills, CA(Zone 8a)

Oh, I DO, every morning! LOL!!

Ivinghoe Beds, United Kingdom(Zone 8a)

Dear Oblambert

Slugs and snails? Tell me about 'em...

Here's a remedy: spray sugar or molasses solution or just yeasty beer on your weeds.

The molluscs will make a beeline (well, perhaps a mollusc line) to your weeds. And they'll eat 'em first!

It truly works.

Is that genius, or am I just modest?


(Zone 6a)

John.....sounds ingenious to me:)

Will give it a try.


PS: After eating the weeds, I should have well-fed huge slimy slugs that will have a larger belly capacity....guess they will really destroy my veggies then. LOL

Newnan, GA(Zone 8a)

and they'll be twice the size and can travel faster! LOL!

Wake Forest, NC(Zone 7b)

What a relief- I thought I was really doing something bad to deserve getting BER.

Now all I have to do is pick and compost the poor little BER stricken tomatoes and wait for a later day. And maybe some less stormy nights too. Since I have leftover dolomite, I might throw a pinch or two around the tomatoes

Chillicothe, OH

Tsk. You guys. Instead of schpritzing the weeds with beer and ending up with a bunch of hung-over slugs with beer bellies and in need of a twelve-step program, you should pour the beer into a jar lid and let them have all the beer they want. At which time they will climb in and rapidly turn themselves into beer-marinated ex-slugs.--Melis

Clinton, CT(Zone 6b)

pbyrley....In this year's soil test, UConn suggested I not use dolomite because of the magnesium in it but swtich to calcitic limestone. Last year I raised the pH from 5.7 to 6.1 with dolomitic limestone. Need to raise it a little more this year but the soil has an excess of magnesium in it. That can block calcium uptake (soil has a barely adequate calcium level as it is).

San Diego, CA(Zone 10a)

COMPOST! Problem has gone away since I started adding plenty of grass/leaf composted material to the dirt. Will be harvesting tomatoes by the colander here. Not a single BER to be found. You must compost your soil first.

Thumbnail by stevelvv
Wake Forest, NC(Zone 7b)

Thanks David_Paul,
I will forgo the dolomite although I don't think I can find the limestone around here.
As stevelvv suggests, I had already planned to compost the garden boxes this Fall/Winter now that the dirt level has settled a couple of inches. This year, they may get chopped up brown leaf mulch in the Fall and as much compost as I have, I'll put it on top of everything. Thanks again everyone.

Thumbnail by pbyrley
Whitesboro, TX

Try soaking eggshells in a couple of gallons of water overnight & pouring it on base of plants & laeve eggshells there when finished. Your problem is a calicum defiency which I had earlier this year & since I've done that every fruit looks great. That's the cheap & easy way to fix the problem for me abnyhow. Hope that helps. Happy Gardening Y'all

Evansville, IN(Zone 6b)

Grow turnip greens as a fall/winter cover crop and till them into the bed. Broadcast the turnip seeds densely for the best cover and green fert. yield ... IOW, don't plant the turnips in neat little rows.

Shullsburg, WI(Zone 5a)

No doubt, soil with a full complement of nutrients will help tomatoes overcome some degree of BER. Just like healthy people can overcome many germs/diseases, etc. However, I didn't note any of these supplemental tests being done with a set of "control" plants! Both in this thread and many others on the forum.

With this BER problem as well as with such nebulous factors as "companion planting" a comparison test must be done to actually evaluate the effectiveness of the "change". With plants there are so many factors that can effect the outcome (temperature, light, seed quality, water quality and quantity, soil composition, etc) that a side by side comparison is essential. And even the side by side comparison may be inaccurate if the roots of the test plants intermingle. But that brings a bunch of other unknowns into the game. As you can see above, many people will believe what they want to even in the face of facts to the contrary.

Salem, NY(Zone 4b)

Koriput, this is a very old thread that goes back to 2008.

There's a much more recent one with lots more information still on the first page and I've linked to it above.

Hope that helps,


Liberty Hill, TX(Zone 8a)

It started in 2002, that 11 years ago, wow!

Anderson, IN(Zone 6a)

My larger Tomato types tend to have problems , Tomato plants are blossoming , however , the overwhelming amount of rain and humidity , stems are getting rot near the Blossom stems ,
So I will water and powder with white school chalk ,, it seems to have helped a few times previous ,
Lots of water this year ,,

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