Calcium, Epsom Salts, and BER

anney(Georgia 8)May 15, 2007

This GardenWeb link on BER says that some have reported that foliar feeding of Epsom salts aids in the uptake of calcium by tomato plants.

Once the problem develops, quick fixes are difficult. Stabilize the moisture level as much as possible, feeding with manure or compost tea is recommended by many, foliar applications of calcium are of questionable value according to research because of poor absorption and movement to fruit where it is needed but many have reported that foliar application of magnesium (epsom salts) can effect added calcium uptake.

If one's soil has sufficient calcium, would this mean that one's soil is deficient in magnesium or just that foliar feeding provides much quicker access to magnesium than the roots can take up from what's available in the soil?

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shelbyguy(z5 IL)

calcium often locks out magnesium

    Bookmark   May 15, 2007 at 10:15AM
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wvtomatoman(z6 WV)

"If one's soil has sufficient calcium, would this mean that one's soil is deficient in magnesium or just that foliar feeding provides much quicker access to magnesium than the roots can take up from what's available in the soil?"

Nice multiparted question. :-) No it does not mean that the soil is deficient in magnesium. Foliar sprays allow quicker absorbtion. Magnesium helps strengthen cell walls and improves a plants' uptake of nutrients (nitrogen and phosphorus as well as calcium BTW).

It is fairly rare that soil is deficient in magnesium. If magnesium deficiency was the problem you'd see other signs (yellowing leaves between the veins, stunted growth, etc.). Tissue has been taken from plants with a BER problem and it was found that there was enough calcium in the plant, but the plant couldn't distribute it properly.

I think Epsom salts improves plant performance, however some people argue that it doesn't help and/or isn't needed. One thing is for sure, if you overdo it with Epsom salts the plant will be big and bushy, but will also fail to set fruit. I know this for a fact because I purposely overdid it and that's what happened to me. However, should you overdo it quit with the foliar spray of Epsom salts and within a flowering cycle or 2 (2 to 6 weeks for tomatoes) the plant will recover and go back to setting fruit.

I hope I've answered everything. How correct it is remains to be seen. :-)


    Bookmark   May 15, 2007 at 2:11PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Too much deep analysis for this old man. All I know is that Epsom salts works on a lot of things, including tomatoes, and BER always cures itself and goes away if the plant is just left alone. It's 'mater magic! ;^)

    Bookmark   May 15, 2007 at 2:30PM
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kubotabx2200(Zone 5b NH)

If your fertilizer has calcium and magnesium in it already you do not need to add Epsom salts.

    Bookmark   May 15, 2007 at 2:40PM
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Epsom salts is cheap. At a tablespoon per gallon of water, it hurts nothing to feed your plants whether foliar or at the roots.

If you are growing "certified organic," you should not feed Epsom salts unless you have tested your soil and it has proven deficient in magnesium and would benefit from the addition of magnesium sulfate ... that apparently is the rule.

I have found over the past few years that where I applied Epsom salts to the planting hole, the tomatoes did better than those that were not fed. Also, I found seedlings to benefit from an Epsom salts foliar application. But whether the it was the foliar application or what soaked in at the roots, I cannot tell you. Just my experience.

With regard to blossom end rot, the causes are far more varied than can be cured simply by the addition of calcium, Epsom salts or any other form of magnesium or trace minerals. Extended periods of very dry soil, chronic saturated soil, root pruning, excessive tilling, and genetic problems all can inhibit or be involved in the inability of the tomato plant to take up calcium and efficiently distribute it to the developing green fruit.

    Bookmark   May 15, 2007 at 4:25PM
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anney(Georgia 8)

Thanks, folks.


I don't think it's true that BER will always go away, though it often shows up in fruits that have developed BER before the weather has stabilized and doesn't occur after summer has really set in.

A tendency toward BER-development seems to be part of the genetic makeup of some tomato varieties, so under varying conditions, BER will develop on those tomatoes but not in other varieties.

With the field of plant genetics expanding, there will surely be plants "created" that don't have this tendency to develop BER, though I suppose it will always be necessary to grow tomatoes under the best conditions to have really good fruits even with resistant varieties.

I guess gardeners are the original experimenters! We hope to find a magic bullet for the pests, diseases, and less than optimal performance of our garden progeny with some common pantry ingredient, no less... That this experimenting teaches us something in the process through success or failure is truly lagniappe -- one of my favorite though seldom-used words. :-)

Just this year I've become aware of the research showing that foliar feeding of plants is overwhelmingly beneficial to them. The plants' immediate utilization of the sprays is something between 90% & 95%, while using the same solution to water the roots at the base of the plant results in only about a 10% utilization of the ingredients! That's an impressive difference. And the intake of foliar sprays if done at the right times (mornings and evenings when the leaves' stomata are open) is extremely fast. Within 60 minutes, the solution-ingredients are found dispersed throughout the entire plant in trials.

Now, the trick is to feed them with the right goodies!

    Bookmark   May 15, 2007 at 5:14PM
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anney(Georgia 8)

My mistake was to say that foliar feeding is best done when the leaves' stomata are open. That's wrong. It's best done when they're closed, and that's when the sun isn't directly overhead.

At the bottom is a link to one article describing the benefits of foliar feeding. There are others, too. Here's one by SprayGrow, a commercial company. Most sites advise foliar feeding to correct nutritional deficiencies but of course some recommend that you make your soil as fertile as possible and foliar-feed your plants, too.

Here is a link that might be useful: Foliar Feeding of Plant Nutrients

    Bookmark   May 15, 2007 at 5:28PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

anney - I'm not faulting you for all your research. If it appeals to you to do it then do it by all means. ;) I just take a more laid back approach to gardening.

And I worry sometimes that too much tech talk can be quite intimidating to new gardeners (who tend to way over-complicate the process anyway). And I fear it might encourage that strive-for-perfection-in-the-garden mentality that is a source of discouragement for many.

All gardeners aren't experimenters and not all of us seek the magic bullet cure. Most just want to grow stuff and eat it. And many of us love being part of the process as nature does it. We are content to accept nature's flaws - or what WE see as flaws.

So I prefer to also let folks know that as someone always posts here - "tomatoes grow like weeds". They are one of the few garden veges that can thrive on neglect! That they simply don't require all the analysis and TLC we seem determined to give them and that trying to apply the results of all that analysis often does more harm to the poor plant than good.

Folks have been trying to "understand and conquer BER" for eons. But there are simply too many contributing factors to eliminate it with some analytical controls imposed by the gardener. If instead, one recognizes that BER is a natural reaction of the plant to some unknown (to us not the plant) circumstance it doesn't like and give it a bit of time, it will fix itself. The plant knows what to do. ;)

In going on 50+ years of growing tomatoes I have done at least 50-75 varieties and not one of them that has developed early season BER has failed to fix itself and go on to live a happy and productive life.

Gardening is supposed to be fun and if we let it become too much like a school homework assignment it isn't quite as much fun anymore. ;^)

    Bookmark   May 15, 2007 at 6:46PM
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anney(Georgia 8)


I think gardening should be fun, too, but people gradually come to understand more and more about what they're doing.

There's different kinds of folks, and that's good. I have an analytical mind, so to speak, want to know not just that something's happening but WHY it's happening. That's fun to me! And I'm not alone.

As far as BER goes, for three years I had it on every single Park's Whopper Tomato I grew. It didn't appear on any of the other varieties I grew those same years. That's when I finally began to wonder if it was the "fault" of different varieties of tomatoes and other veggies that get it under some conditions (did you know that WATERMELONS can develop BER?) and not mine! I'd done everything recommended -- prepared the soil with lime/calcium ahead of time, watered regularly, fertilized just right, waited the season out, ad nauseum. I had to discard at least 80%-90% of those Whopper tomatoes each year. Finally, I stopped growing them and started looking for varieties that didn't develop BER. That's the point -- there are varieties that don't get it, at least not to the extent of no crop produced, and in some cases, perhaps admittedly rare, maybe you can do something about BER and lessen its impact.

So, it's a balance between laissez-faire, letting things take their course, and figuring out what's wrong when you put a lot of energy and planning into making your garden grow.

I've been gardening for a LONG time, too, and none of the varieties I've grown developed BER except sporadically until I began gardening here in Georgia. It was bad for every gardener I spoke with last summer, all of them trying to buy calcium sprays in the garden centers! The weather must have been part of the problem since everybody has a different system for growing tomatoes. But it was the third year for me with those Whoppers and I'd had enough.

And I agree -- there may be newbies for whom gardening is overwhelming, but I think people absorb what they're interested in or need to know at the moment. What that is depends on their prior experience and knowledge. The GardenWeb search function is of great value -- when you're ready with a new question, it's probably already been answered somewhere here.

    Bookmark   May 15, 2007 at 7:20PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Ahhhh, anney there's the problem. I retired my analytical mind when I retired my body nigh on to 5 years ago. It's gone dormant - the mind, not the body. Good luck with the Georgia dirt. I'll send you some Arkansas dirt if you want. Whoppers seem to love it. ;^)


    Bookmark   May 16, 2007 at 12:21AM
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korney19(z6a Buffalo, NY)

All you need to do is let a plant wilt one day, or miss a watering, and you can get BER. And BER can get "preprogrammed" into a plant with no fruits yet, and show up when the fruits show up. I don't recall how that happens, it has been stated here in the past many times. Maybe damage occurs to the plant from the wilting that cannot be reversed and therefore calcium movement to the fruit has a problem, even though sufficient calcium is available or found in the plant.

    Bookmark   May 16, 2007 at 12:59AM
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an old man told me this...put a handful of epsom salt and your fertillizer in the transplant hole, bury under roots a couple of inches, i did...12 mixed kinds of tomatoes from local nursery produced over 300 quarts (canned) in a raised bed 3x12 in chico tx...i filled in all holes with forrest compost from under oak trees (mycorrhiza)...the water was from a 240 ft well (really good), watered every other day in sandy loam soil...i still use epsom salt in garden today...i think it makes calcium available to plant in a good ratio...just guessing..the indian

    Bookmark   March 20, 2014 at 7:12AM
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oklahoma gardners...check out the mesonet site for ground temperature...very helpful...forgot to mention that better boy produced more tomatoes than other kinds...this season i plan to go bush tomatoes for canning..mountain variety developed in nc....the indian

    Bookmark   March 20, 2014 at 7:23AM
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