Over the past couple weeks I've been trying to mend some BER in my main tomato plants. I've begun a regular watering schedule, with about 2-3 litres every morning. Recently it's been quite hot (28-30C) so I've also done a little watering in the afternoon.

They get liquid fertiliser (sea sol) once a week and have been fertilized with tomato specific fertilizer around 2 weeks ago.

New tomatoes still seem to suffer from BER, yesterday I could see one begin and progress quite alot. I'm not sure what else I could do, whether my watering is off or some other issue.

Thanks in advance.enter image description here

1 Answer 1


There are two possible answers: 1) Your fertilizer regime is providing too much potassium and 2) Your tomato cultivar is a San Marzano or relative.

Given that you're supplying adequate moisture, I recommend completely stopping the use of fertilizers at this point. Too much potassium can restrict the uptake of calcium. From that link:

...according to Dr. Luke Gatiboni, an associate professor in Crop and Soil Science at N.C. State University, “it is well known that nutrient interactions occur in soils, meaning that the amount of one nutrient such as potassium if in excess can negatively impact root uptake of other nutrients such as calcium and magnesium; research has validated this. However, supplying calcium, magnesium and potassium in ideal ratios that exceed plant requirements may indeed create nutrient imbalances and deficiencies.”

Let the current fertilizer situation at least partially rectify itself via leaching. This should correct the problem. Here is more information US Michigan State University about preventing BER. If you haven't already done so, I recommend that you have a soil test done if the problem doesn't resolve via leaching.

I mentioned San Marzano tomatoes earlier in this answer. Like many of the paste tomatoes, these suffer from BER but IMO but get it worse than any other paste tomato. I've grown them within feet of other varieties that never showed BER at all while losing half of my San Marzano harvest to BER. I've stopped growing them for that reason.

  • I'll cease fertilising and see how it goes, thankyou very much.
    – Blazeboy01
    Commented Jan 16 at 6:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.