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Epsom Salts when how much/plant?

Posted by vrkelley 7 Indoor (My Page) on
Wed, Dec 24, 08 at 14:18

Lots of questions about Epsom salts. I did some searching around and couldn't find much. Anyone soaking feet or whatever, is that the same stuff that tomatoes can use???

B. How do I apply epsom salts to blooming indoor tomatoes. On top of the soil or some sort of mixture with water???

C. Does it go with some sort of miracle grow fert???

D. How much salt per blooming indoor plant???

Follow-Up Postings:

RE: Epsom Salts when how much/plant?

I don't grow tomatoes indoors, except to start them and hold seedlings maybe 6 - 8 weeks.

Do you mean how much Epsom salts to feed tomatoes growing in greenhouses or long tunnels? If so, you should consult Mississippi State University facts sheets for greenhouse tomatoes and look at the recommended fertigation formulations and schedules.

In greenhouse culture, the Epsom salts will be fed dissolved in vats and fed through automatic drip lines.

If you mean feeding potted tomatoes (which I grow outdoors during the summer), you may dissolve roughly a tablespoon of Epsom salts per gallon of water along with your Miracle-Gro type fertilizer and feed according to what the container will absorb each time. Generally for me, that is about 1/2 to 1 gallon per 10-gallon nursery tub with one plant.

However, I don't feed Epsom salts and Miracle-Gro each time I water, as it is only necessary to feed each vine, grown the way I do, about once per 10 - 15 days. The rest of the time, I only give water unless I notice leaf signs that indicate nutrient deficiency.

Again, in greenhouse tomatoes, this would be different. A buddy of mine feeds four times per day, high phosphorus formula, plus calcium and Epsom salts, all in proportions dictated by whatever professional advice he has gotten, and he grows two indeterminate vines per 5-gallon bag of coir fiber and trained to single apical meristems per vine.

General Greenhouse Tomato Info

MSU Greenhouse Tomato Handbook

Now, if you just want to add Epsom salts to raised bed tomatoes or to at-grade tomatoes, I'd put a handful per planting hole and take one of those little hand rakes and stir it in good at transplant time. Then later in the season like at first fruit set, I would hit each vine with a tomato formula Miracle-Gro type fertilizer with that tablespoon per gallon of Epsom salts added. Or if you side dress your vines with granular tomato food, water than in with Epsom salts at 1 Tbs. per gallon.

RE: Epsom Salts when how much/plant?

I've always wondered why folks use Epsom Salts. Since it's just Mgsulfate I can see using it if Mg++ is in low concentration but otherwise I would expect that most inground plants would have enough Mg++ from the soil.

And I would expect that most container mixes would have enough sincemost folks Iknow use other amendments with Mg++ in them for container growing.

I've never used it so what am I missing since my plants seem fine and dandy

So convince me why I should use Epsom Salts other than for soaking feet. LOL


RE: Epsom Salts when how much/plant?

I agree with Carolyn. I did some "A/B" trails with and without Epsom Salts in an EarthTainer this past season, and I so no material difference. Someone, please enlighten us on what we are missing (where is Dice when you need him).


RE: Epsom Salts when how much/plant?

Well ... for supplementing micronutrients that may be missing in soilless growing media, Carolyn.

Besides, after you get done soaking those doggies, no reason to pour the salts down the toilet when you can recyle them through the raised beds :::smile:::

RE: Epsom Salts when how much/plant?


If you are already using fertilizers such as Tomato-tone that contains micro-nutrients, why then would supplementing this with Epsom Salts make sense? I really want to understand the "science" of what Epsom Salts contributes that is not already in Tomato-tone.


RE: Epsom Salts when how much/plant?

I don't know, Raybo. All I know is my buddy Paul Mayse has one vat full of high phosophorus liquid fertilizer and one vat full of calcium nitrate + Epsom salts. The auto-pumps feed the fertilizer mix four times a day and the other vat feeds out once per day with the calcium/epsom salts solution. Paul has five hoophouses full of beautiful tomato vines every year.

An old-timer once told me Epsom salts facilitates uptake of calcium otherwise bound to the soil. Don't know if that has anything to do with it ... you know, BER prevention, maybe.

Why don't you should ask a professional greenhouse grower why they include Epsom salts in their fertigation schedule when growing tomatoes in coconut fiber bags, soilless medium, or hydroponically.

Or maybe if someone would read up on it, they would find the answer. There's plenty of information online about feeding Epsom salts as part of hydroponic fertigation for tomatoes.


RE: Epsom Salts when how much/plant?

I wouldn't dare use it after soaking my feet..ruin the taste of good tomatoes.

RE: Epsom Salts when how much/plant?

Maybe we should concentrate on the original post ... the person apparently wants to know what the purpose and proportion of Epsom salts is for "indoors" tomato plants.

I'm guessing the question pertains to hydroponic method or soilless mix, both of which would benefit from a complete nutrient package. So, we're not talking about garden soil. And maybe we're not talking about earth boxes in particular, or some container in which Tomato Tone granules would suffice.

Does Tomato Tone make a water-soluable fertilizer like Miracle-Gro? Does it contain the complete tomato nutrient package?

Meanwhile ... Merry Christmas. I'm headed out for sister-in-law's place for awhile. BBL.

RE: Epsom Salts when how much/plant?

Save it for your peppers. Tomatoes want calcium more than they want magnesium, in my limited tomato experience. Peppers are much hungrier for the magnesium and sulfur.

RE: Epsom Salts when how much/plant?

In regards to using Epsom Salts, which is magnesium sulfate,
I can advise regarding outdoor use in the garden or field but hesitate to do so for greenhouse propigation. My containers of Miracle Grow/Peters are out at the lake but as I recall both contain a quantity of magnesium. So if you are using it to feed seedlings in the greenhouse you likely have enough.

Now lets talk about the garden or field crops. Certain areas of the country are rich in mag, others are not. Typically, so called agricultural limestone contains a small percentage of magnesium carbonate along with the calcium carbonate, so if you use this, for example to adjust your soil ph, you are likely to get a good shot of mag as you apply it.

I live in far western Pennsylvania, about centered north and south on the state. THERE IS A TERRIBLE SHORTAGE OF MAG IN THE SOIL HERE! So we need to suppliment during fertilization to make up for this. When I was operating
my orchard I would add a pound of epsom salts to each 80 gallon spray tank of chemicals. Trees and plants readily absorb nutriants through the foliage--this is referred to as folliar feeding--so by adding it to my insect/anti fungal sprays I got double the bang for my time. (There were some other suppliments added on occasion). It does not take a lot of mag to satisfy a plants needs and once they have enough adding more is just a waste. Fortunately, epsom salts is pretty benign, i.e. does not seem to root or foliage burn, and since it is so readily soluable, rain and
or watering pretty well dilutes it and washes it out of the root zone.

When I spray my tomato plants to deal with the blight/et al
I add Miracle Grow or Peters to the tank mix per direction and also 1 tablespoon of epsom salts, 1 tablespoon of
potassium carbonate, and 1/2 teaspoon spreader sticker to each gallon of spray. Once the tomatoes are about an inch in diameter I stop the spreader sticker and just have to spray in the gaps between rains as the sticker is difficult
to wash off the fruits.

And it works!

RE: Epsom Salts when how much/plant?

  • Posted by jll0306 9/ Sunset 18/High De (My Page) on
    Sat, Jan 3, 09 at 15:59

It appears that a foliar feed of ES MAY be helpful in combating BER:

"...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."

From the Tomato Forum FAQ section on BER

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