Using Cal-Mag+ for BER

[Greatgardens]

I had a severe bout of BER this season with one variety. It was an F1, and BER was about the only fault I could find (tasted great!). But nearly every tomato showed rot or at least the start of it as a small depressed scar on the blossom end. So far I've lost about half the tomatoes produced. No watering issues that I could see, and plenty of Dolomite in the mix. It was not a fresh potting mix -- it was last year's mix freshened with new fertilizer and lime.

This was grown in a Gro-Bag, and in fact the same Gro-Bag that I grew Stellar F1 in last year. Had maybe 1 or 2 Stellar fruit with BER -- nothing remotely like this. Too late to do anything about it for this year, but for next season:

If you use a calcium supplement...
How do you use Cal-Mag+ (or similar) in your containers?
How do you apply it in EarthBoxes?

I'm looking for type, quantity, and frequency of the application. I'm also curious if you have ever had a severe occurrence of BER?

[Labradors2]

BER is supposedly caused by uneven watering, but I had one plant with horrendous BER that it refused to grow out of. We had a dry summer, and all my plants were hand watered by me in exactly the same way. I eventually pulled that plant because I got so sick of looking at the half-brown tomatoes. I didn't add any Cal-Mag to the planting hole of any of my plants this season.

[PaulF]

For me BER is not a problem because everything has gone to in-ground growing. Years ago about ten plants went into 5 or 10 gallon buckets and grow-bags. Every year BER was common in those container grown tomatoes.

No matter what the watering regimen the early fruits had BER and even some into mid season. My growing medium was soilless mix with supplemental fertilization throughout the season.

It wasn't worth the effort so all tomato growing returned to in-ground with no real problem since then.

[Greatgardens]

In-ground may ultimately be the answer for me, but I'd like to stick with containers if possible. I'll give it at least one more try in a container.

[zipcode]

Tomatoes use quite a bit of calcium, so in soilless mix and if your water is not hard, it might help. You can always try, just be careful of pH going too high (check runoff pH at the end of the season to see where you're at).

[Greatgardens]

What happens if the pH goes too high? I have read about the not letting the pH go high, but I don't recall seeing what happens as a result. Just curious about this.

[zipcode]

The plants don't absorb certain micronutrients anymore, most usually seen as newer growth having some problems like chlorosis, reduced internode length, thinner leaves, and worse if the problem persists.

[PaulF]

I stage a yearly battle against high pH. Our soil's natural pH is above 8.4 so elemental sulphur needs to be applied yearly. I have also used ammonium sulphate to add sulphur and nitrogen to the soil. High pH ties up the transfer of several essentials to good growth for plants.

[MissS]

When I was growing in containers, I used to add a TUMS to control the blossom end rot. It seemed to help for the two years I used it.

[Greatgardens]

Originally Posted by MissS

When I was growing in containers, I used to add a TUMS to control the blossom end rot. It seemed to help for the two years I used it.

Never head of that before. Did you crush them or put whole tablets in? Just one? Apx. what size were your containers?

[b54red]

I rarely have blossom end rot on my tomatoes but I did have a few cases this year. We had some severely dry weather and very hot temps which made keeping the soil evenly moist much harder than when we have the usual rainfall. Where I had a lot of blossom end rot was on my bell peppers. I talked to a friend of mine that grows a lot of them and he also had a big problem with it this season even though we both mulch our plants heavily. It seemed for about six weeks the only way to stop it was to give the plants a watering every single day and sometimes twice in a day. I guess bells just don't have the extensive root system to keep them moist when the temperatures hover around a hundred for weeks on end.

No mater what mix I used when I grew some of my tomatoes in containers I would still get some blossom end rot on most varieties when it got really hot and dry. Regularly fertilizing with TTF helped a good bit but down here it is almost impossible to keep the soil moisture even, especially in containers, when the really hot weather arrives.

Bill

[Greatgardens]

Does excess water cause BER problems? "Evenly moist" is tough to do in a container. I realize that water-logged potting mix is also undesirable for other reasons, but seems like erring on the side of "too wet" may be the lesser of the evils. How about these "water controlled" mixes that claim to provide moisture when dry and take up excess water?

[PaulF]

From what I have been able to gather it is the extremes of water that is some of the cause of BER. Too much water followed by too little and then back again in a cycle.

[GrowingCoastal]

I've seen differences in water requirements in different varieties. Both SOTW and Paul Robeson wanted to be kept a lot wetter than others. I had to water those two, in containers, almost every time I saw them in order to prevent BER.

[Yak54]

When I began using grow bags I also had issues with BER for the first two years. After that I switched to a 4-18-38 fertilizer with Cal. Ni. & Mag. Sul. liquid feed applied 1 or 2 times per day. Also started checking moisture twice daily in the soil less mix of the grow bags and BER went away almost totally. Now I'm a happy camper even though this is labor intensive but the productivity is worth it.