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Applying Tums to tomato plants is simply a waste of time and money. Photo: Brett Hondow, Pixabay,

There is no limit to the human imagination … nor to far-fetched ways to treat our plants. Here’s one example among many, the belief that giving antacid pills, specifically Tums, can be useful to tomato plants.

The tip suggests placing a Tums antacid pill at the base of the tomato plant, then watering well afterwards. Exactly what this is supposed to do to help the plant is rarely mentioned. Just do it: it’s good for your plant. And I’m sure plenty of people blindly follow this advice.

I can, however, tell you where the idea originally came from and also why giving Tums or any other calcium-rich antacid tablet to your tomatoes won’t work.

Preventing Blossom-End Rot

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Blossom end rot is caused by irregular watering. Photo: Scot Nelson, Flickr

Tomatoes often suffer from blossom end rot (read Tomatoes and Peppers: How to Avoid Blossom End Rot for more details on this disease). The tip of the fruit becomes brown and sunken and the fruit begins to rot. And blossom end rot is known to be caused by a calcium deficiency. And that’s why Tums pills are supposed to come to the rescue, as they are mostly composed of calcium carbonate. Calcium, in other words, and in a highly soluble form to boot. That should solve the problem, shouldn’t it?

But that’s misunderstanding the situation. Blossom end rot is rarely caused by a lack of calcium in the soil, but rather by a lack of calcium in the plant. Calcium is abundant and available in almost all soils, even in artificial soils or poor quality ones. In fact, it’s one of the most abundant elements in soils all over the world. Almost any soil contains more than enough calcium to satisfy a tomato plant. And essentially all fertilizers also contain calcium as well. As a result, the average tomato plant has an abundance of calcium in the soil in which it grows: you don’t need to add more.

In fact, blossom end rot is really due to the inability of the plant to absorb the calcium present in the soil. And this is related to moisture stress and uneven watering. If the plant lacks water during the critical period of fruit formation, the roots can’t absorb all the minerals that are available and therefore what little sap now reaches the fruit will be carrying less calcium than it should. Since the fruit isn’t getting sap of the quality it requires, a calcium deficiency occurs … and blossom end rot sets in.

Just Keep the Plants Moist

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To prevent blossom end rot, just water. Tums aren’t necessary! Photo: Graphicstock

So, if you water your tomato plants more regularly, thus avoiding moisture stress, the fruits won’t suffer from blossom end rot. Applying Tums won’t be necessary, nor will using a fertilizer rich in calcium. Just keep the plants evenly moist and all will be fine.

So, if you apply a Tums to the soil at the foot of a tomato plant and you water it, as the garden myth recommends, true enough, that will cure future cases of blossom end rot … but because you watered, not because of the Tums.

Just skip the Tums and go straight to step 2, watering. It’s as easy as that!20170821A Brett Hondow, Pixabay

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

12 comments on “Garden Myth: Tums for Tomatoes

  1. Desiree Bradbury

    I water very regularly. As the plants are just starting…every day….when they are better established, every other day…in heat sometimes every day. So my blossom end rot clearly has little to do with watering.

    • Have you ever dug up a tomato to look at its root system? If the roots have a problem, are too few or weak, they won’t be able to absorb soil minerals. Have have you ever applied mycorrhizal fungi to young plants (they help roots absorb minerals).

      If the above thoughts don’t apply, the obvious question is whether it is really blossom-end rot. Is it possible that this is a disease of some sort, for example, late blight? It results in similar dark brown depressions.

      Solving tomato question is verrrrrrry complicated!

      • James Beckett

        im running a RDWC and very strict with the nutrient and ph levels … definately not water issue .. i had a couple of my tomatoes start to turn and started spraying the leaves once a week with a crushed tum on a gallon of water no more from then on.

      • Well, I have no idea why that might have worked, but I’m glad your tomatoes recovered.

    • i water religiously and still got bottom end rot. After using tums i got amazing fruit. i grow ton of tomatoes and tums are my go to. never fails. I run soaker hoses and water my tomatoes at least twice a day so watering is not an issue. Not sure why so many folks are against using tums since there is no adverse effects to using it .

      • Asia, I had the same experience. Even with careful watering I still got blossom end rot. But after using Tums, I’ve not lost even one tomato to blossom end rot, now for 5 years.

  2. I had blossom end rot many years until I started giving them anti-acids (Tums) I have not had it since I started watering in ground up Tums when I plant. I water regularly so I don’t think watering is the problem. Again, this year I’m using Tums and hoping for the results I’ve gotten in the last 3 years…..no BER.

    • Good for you… but the use of Tums on tomatoes has been studied and it was found to be ineffective. Of course, your conditions could be different.

  3. Ronald J Denicola III

    Great info but in some cases maybe having the extra readily available calcium is the reason you see results because the soil life web isnt built up well enough to allow for the plants roots to up take the nutrients already present but take a bit to transfer.

    • Everything is possible, but is the soil situation is that poor, i.e. so bad the roots can’t absorb available calcium, which is a pretty basic and easily absorbed mineral, any added calcium would probably be “locked up” chemically anyway.

  4. John Myers

    For the last 10 years at least, I have always had blossom rot issues with my San Marzano tomatoes, up to in some years, 25% of the fruit. Last year, I placed a single tum in each hole before putting in the tomato set. Guess what–out of 30 plants, I had maybe a dozen tomatoes TOTAL with blossom rot.

    While the Laidback Gardener claims that Tums–calcium carbonate–doesn’t work, I say they do. While LG says the issue has been studied, I don’t see any such study on the internet. In any event, only a double blind study could settle this issue once and for all. Until such a study is made, what do you have to lose by trying Tums if you have blossom rot problems? Tums are dirt cheap, especially if you get the generic ones at Wal-Mart.

    P.S. My sister saves egg shells–another form of calcium carbonate–and puts them under her tomato sets. She swears by her shells.

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