Managing Calcium for Potted Tomato/Pepper Plants?

4 years ago

I'm still figuring out how to manage calcium levels with potted tomato plants. Blossom end rot has been an issue for the last year or two and I want to get better at this. Currently I have a lot of tomato /pepper plants in 5 gallon buckets. The soil is new and straight from the hardware store. Due to PH levels, I'm planning on using gypsum instead of lime. But in general:

1. What product are you using to add calcium to your potted tomato plants?

2. How much calcium are you adding to your potted tomato plant soil?

3. When and how often?

I'd love to hear any feedback or routines that you've had success with.

Featured Answer

gardengal48 (PNW Z8/9)

4 years ago

If the OP is still open to info, this may help.

I also grow tomatoes in containers....and have for years. A 5G container is not large enough to accommodate the growth of anything other than a dwarf patio type plant. I grow mine in 20-25G black plastic tubs they sell trees in at the nursery. And the roots still fill the container at the end of our relatively short growing season.

With a smaller, root filled container, it is difficult to maintain the consistent soil moisture necessary to allow the uptake and transport of the Ca. And as has been previously stated, it is the consistency in maintaining proper soil hydration that reduces the instance of BER, regardless of what the Ca levels maybe.

Because of the nature of potting soil and the almost closed system presented by container growing, the grower needs to fertilize. There is no other way the plants can access the nutrients they require. And fertilize frequently....every time you water you are leaching nutrients out of the potting media. And tomatoes with their heavy fruit production are also heavy feeders so this becomes even more important.

"weakly, weekly" is the watchword for fertilizing container plants but may need some modification depending on the watering frequency necessary for your situation. Essentially it means using a full range liquid or water soluble fertilizer at no more than half strength on a weekly basis assuming the need for water is only a couple - three times times a week. If you need to water more frequently, like daily, because of your weather conditions or size of container, then increase the dilution to quarter strength and apply with every other watering.

For container gardening, the fertilizer is just about as important as the quality of the potting media. I add Osmocote Plus to my soil mix before potting. But it is not enough to support the plant all season, given the need for almost constant watering and the heavy nutrient demands of the growing plants. So I supplement with a liquid or water soluble fertilizer that has a full range of micronutrients/trace elements as well as the standard NPK. Dyna Gro products or even Miracle Gro all purpose plant food are decent choices but there are others. You just need to read the labels to see if they offer a full range of nutrients.

Following this methodology, I have never encountered BER. Nor have I had to resort to a calcium supplement. If you must, Bonide makes one called 'End Rot'.

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Comments (8)

Labradors
4 years ago
I use Promix for herbs and veggies in my containers for compact tomatoes.

BER is caused by uneven watering. It is not due to a lack of calcium, but because the plant is unable to take-up calcium because of the stress. People add calcium and think it has helped, but really the problem has gone away. It is usually the plum-type tomatoes that are affected by BER, and usually just the first few fruits. If you can keep the watering consistent and if it doesn't rain too much, everything should be fine.
mindshift
4 years ago
Positive attributes of potting soil are its free-draining quality and its lack of pathogens (which is most important for seed germination and seedling survival). But, potting soil may contain little nutrient value on its own. It is most often a combination of peat moss, coconut fiber (coir), and composted tree waste from sawmills, along with perlite and vermiculite. Sand and soil are rarely used because they are heavy. The terms natural or organic mean nothing. There is no federal standard for potting soil as there is for organic food products. The term compost can refer to sewage sludge.

You can add calcium and other rock dust to potting soil, but these take time to be utilized. Liquid fertilizers give you quick results. Look for those that include more than NPK nutrients, such as GS Plant Foods Organic Liquid Kelp, or Fox Farm Grow Big and Big Bloom formulas, or Plant Magic All Purpose Organic Plant Food.
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Generally the 5:1:1 mix has lime added, unless there is a specific reason you want to keep pH extra low, The BER may not be because of an actual Ca deficiency. An imbalance of P or Mg can create antagonistic deficiencies. High humidity levels, and soils that are either too wet or too dry also cause BER. In short, the plant needs a CONSTANT supply of Ca available during the formation of every cell or the cells will be weak/deformed. ANY disruption of the nutrient stream makes greater the probability of a culturally induced Ca deficiency and the accompanying BER. Al
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Hello, Our favorite tomato expert Carolyn137 wrote an excellent response to a question about Blossom End Rot (BER) and I am quoting it here: With BER there is NO problem with absorption of Ca++ though the roots. The problem is maldistribution within the plant that can be induced by a number of stresses which include uneven delivery of water, too much N, growing in too rich soil, too hot, too cold, too wet, too dry you name it. As the plants mature they can better handle the streses that can induce BER so usually it goes away. The two exceptions are first, if the soil has NO Ca++ as confirmed with a soil test, and that's a rare condition, and second, if the soil is too acidic in which Case Ca++ is bound in the soil. Again, adding lime, egg shells and on and on can not and will not prevent BER b'c absorption of Ca++ thru the roots is OK. Paste tomatoes are especially susceptible to BER and I think someone in a post above mentioned that. If you go to the top of this first page and click on the FAQ link and scroll down you'll also find an article about BER in case some of you have never looked at the FAQ's And there';s some darn good articles there as well, but I wouldn't pay any attention to the variety list b'c it's way out of date. The old information about BER being caused solely by lack of soil Ca++ has been shown to be wrong with research that's been done in the last 20 years or so, but it's going to take another generation before the real story gets into books, websites, magazines, etc. Most of the better websites already have the correct information. BER affects not only tomatoes, but peppers, squash, cabbage, cauliflower, etc., and it's a huge multimillion dollar problem for the industry, which is WHY all that reasearch was done. For instance, when tissues were taken from a plant that has BER fruits and was assayed for Ca++, the normal level of Ca++ was found, it just wasn't getting to the blossom end of fruits. And there's also a condition called internal BER where the fruits look fine, no evidence of BER externally, but when you cut open the fruit the inside is black Hope that helps Carolyn knows tomatoes! Betsy
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edweather USDA 9a, HZ 9, Sunset 28
4 years ago
Yes, uneven watering, and rapid growth early in the season. I never really found a good way to manage a little BER, even though it dissipates later in the season. I'm not offering a cure, nor do I have any affiliation, but, when I started using Texas Tomato Food, BER has disappeared. They do advertise their food stops BER, but I'm always skeptical of claims like that. I bought some because it is the best on the market to feed plants, and also noticed that I haven't had any BER since. Coincidence? Not sure, but I'll take it.
Irish Enterprises LLC
4 years ago
You might find this article by Dr Carolyn Male helpful.

Article on Calcium/BER

or this one is less technical and shorter too.

Garden Myths
newmexmike
Original Author
4 years ago
last modified: 4 years ago
I have to admit, I'm a bit frustrated. I'm trying to get a better idea of what people are doing about calcium with their potted plants. Instead I hear BER "is not due to a lack of calcium" and garden myths.

But I want to keep an open mind here. I could be wrong, I just need some assistance helping me to understand it.

If the plant is in the ground and not in a pot--I agree with the above statements. The plant probably isn't fighting a lack of calcium in the soil. We're in agreement.

But the question is for potted plants. In my case, I'm growing in 5 gallon buckets. At this point many of them are root bound. They are pulling everything out of the soil and will soon produce fruit, which will pull calcium out of the soil constantly. Does hardware store soil in a bucket have enough calcium for a whole season of heavy fruiting plants? Maybe the water from my hose is enough to replenish the calcium needs? I wouldn't rule it out but a quick Google check says 40-80 ppm, so we're looking around 0.00006%.

But I do find edweather's response helpful. He mentions Texas Tomato Food. I looked it up and it specifically states that it has calcium built in, but I couldn't find out exactly how much. To edweather, I'm curious how often you use it and how much.
edweather USDA 9a, HZ 9, Sunset 28
4 years ago
The TTF label says 2.5% Calcium. I use it almost every day. I soak my containers first. I then add about 3 tablespoons to a typical watering can. Then I pour a little on top of the soil so it leaches in. One watering can will spread out over about 8 containers. Sometimes I skip a day, or supplement MG liquid. The main thing is to feed weakly but often.
newmexmike thanked edweather USDA 9a, HZ 9, Sunset 28
newmexmike
Original Author
4 years ago
I want to thank gardengal48 and edweather for the posts—this really helps me out and changes how I think.
- I’ve never grown a dwarf tomato—I want to try that out for sure.
- “Weakly, weekly” I’ll remember this going forward
- With regards to Osmocote Plus, I’ve never mixed fertilizer with the soil before potting. Now I want to experiment with this.
- Edweather—you mention 2.5% calcium. I actually have multiple fertilizers with 0% calcium. I won’t be using that much anymore.
What I take from this is that if you water properly and fertilize regularly, and correctly, and use fertilizer with calcium mixed in, you should very likely be in good shape.

To you both, I really appreciate your help. It has changed my strategy and I’m sure will greatly help moving forward.

Managing Calcium for Potted Tomato/Pepper Plants?

gardengal48 (PNW Z8/9)

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