Kitchen Garden Forum

Has anyone else had problems with blossom end rot on their tomatoes?

We haven't had one BER free ripe tomato from our garden greenhouse but tomatoes in our allotment greenhouse are fine. If it's a problem with erratic watering as is supposed to be the case our plot tomatoes should suffer not the garden ones which have a more regular watering regime.

Then our allotment plot neighbour has the opposite problem - BER in his plot greenhouse but not garden one.

It isn't a variety issue as it is affecting various varieties

No problems this year, but I used to encounter it with plum tomatoes (Olivade) grown in pots in my old greenhouse, though not with smaller varieties. Now we've moved, have a new greenhouse, and the tomatoes are growing in the border. I agree that the problem is about watering, but I think the widely-used term 'erratic watering' is wrong. It's more about recognizing that the plant's water needs vary depending upon the soil, the age of the plant, the variety, and what the weather is like on a particular day. Terry Marshall in his book 'Tomatoes' highlights some research going back almost 50 years, suggesting that the water required by a single plant can vary between a quarter of a pint and 3 and a quarter pints a day, depending upon the weather.

I've had outbreaks of BER for years and, quite frankly, I've given up trying to anticipate the watering needs. I just immediately pick any ripe toms with BER, cut the rot off and eat the rest!

Have had some blossom end rot on greenhouse grown Country Taste. Some fruits affected, some not. Yesterday I picked 2 tomatoes adjacent to each other on the same truss, one of which had BER and the other totally unmarked. This seems, largely, to confound the theory of erratic watering, as they must have had exactly the same amount. Continue scratching head on this one!

Evening Fred, i must admit, i've never been convinced BER is just down to watering. My tomatoes have only ever suffered from this a very few times, and i don't believe that i got things so different in those years.

It's not just down to water. It is down to calcium deficiency, IIRC. But mostly it correlates with erratic watering which affects the uptake of calcium.

I wonder whether long damp periods reducing the plants' water uptake also interferes with calcium uptake ? Or if poor compost is the culprit. I always struggle with BER on my plum tomatoes.

Tony Hague wrote:Or if poor compost is the culprit. I always struggle with BER on my plum tomatoes.

I wondered that too but the plot tomatoes are growing in the same brand compost - although it is a different batch of bags. We are feeding the plants as usual using Tomorite. We've been growing tomatoes for years and never had the problem before and we aren't doing anything differently. Also it's strange that another two friends are having the same problem for for the time this year, In the garden greenhouse literally every tomato has it.

Just to chip in again...I've only every experienced BER with plum tomatoes even though there have been other varieties alongside. These are quite big tomatoes with a lot of flesh and not much juice. I interpreted it as meaning that plum tomatoes need more water (or calcium) than other varieties. As I was growing them in big pots at the time, I think I started adding water-absorbent gel to the compost.

ken wrote:Just to chip in again...I've only every experienced BER with plum tomatoes even though there have been other varieties alongside. These are quite big tomatoes with a lot of flesh and not much juice. I interpreted it as meaning that plum tomatoes need more water (or calcium) than other varieties. As I was growing them in big pots at the time, I think I started adding water-absorbent gel to the compost.

Interesting but ours are a mixture of varieties and none are plum tomatoes.

I have four varieties in the border in the greenhouse.( none of them plum tomatoes) So far, I've had four fruits with BER, from different plants and varieties and like Fredfromosset, neighbouring fruits on the same truss were unaffected.
**puzzled**

Many of you are reporting blossom-end-rotting fruits being adjacent to fruits which are well-formed. This is not unusual and neither proves nor refutes any particular theory about the causes of blossom end rot. There is no theory about the causes of blossom end rot: its causes have been exhaustively studied and researched, and it is tied to the availability, and more specifically the transportation, of calcium in the developing plant. The RHS have published an excellent abstract on its causes and some suggested remedies here.

Received wisdom is that "erratic watering" is the main cause of BER, but it's rather more complicated than that: ventilation, weather, number of hours site is direct sun, humidity — all these factors contribute. This accounts for tomatoes on one site suffering symptoms, while those grown elsewhere do not, despite their being managed the same way — there will inevitably be subtle, but significant, environmental differences between the two locations.

Here's my tuppence worth: don't use growbags. I stopped using them 15 years ago and I've not experienced BER since.

FelixLeiter wrote:Here's my tuppence worth: don't use growbags. I stopped using them 15 years ago and I've not experienced BER since.

The tomatoes in the garden greenhouse that are suffering from BER are not growing in growbags but the ones that are BER free at the plot are growing in growbags with ring culture discs on top.

The plot greenhouse is smaller 8X10 and aluminium and not opened as much - it mainly is ventilated using autovents in the roof. There are only tomatoes growing in it.

The garden greenhouse is much larger 20X10 and cedar and the door is open for most of the day. Tomatoes take up probably about a third of the available space.

I would have thought the plot greenhouse gets hotter than the garden one with less ventilation

It would be interesting to compare conditions in the greenhouses where people have experienced BER this year and what it is that has made a difference this year to other years. I would have thought it was our plot greenhouse that had suffered from much different conditions this year to last rather than the garden one.

I regularly encountered BER but find adding a dusting of ground egg shell into the hole when planting out keeps it away. I rinse shells under the tap and save them until there's enough to go on a baking tray next time the oven is on. Roasted shells are then ground into a gritty powder and kept until needed.

I put eggshells into my compost bin which goes into my home greenhouse in due course... no BER. My son's greenhouse on his plot does not get home compost and this year has BER. But another factor could be the more eratic watering in his greenhouse.

MW