I noticed BER on a few tomatoes on 3 of my 26 plants today. Eight of these plants were transplanted into 20 gallon fabric pots with a peat-based potting mix about 6 weeks ago. They are now ~4 feet tall. All three affected plants are in these 20g pots. The rest of my tomato plants are in raised beds or 5G self-irrigating containers (all of which appear just fine so far). This is my first garden. I am in zone 6b.

What I thought was interesting is that the affected tomatoes are all on the second truss. The tomatoes on the first truss are fine as are the ones on the 3rd+ trusses. Not all tomatoes on the 2nd truss are affected either. At least for now. Two of the three affected plants are very vigorous growers (Cuore di Bue and Costoluto Fiorentino); the other is not quite as vigorous, but is growing well (Pineapple). There is only 1 affected tomato on the Cuore di Bue and Pineapple plants and 3 on the Costoluto. At least, as far as I can tell as the BER is currently not that noticeable except on the tomato on the Cuore di Bue plant.

All of my pots were amended with dolomite lime, bone meal and slow release granular fertilizer. I also fertilize with a low dose of soluble fertilizer every 10-14 days. I do not believe there is a lack of calcium in the pots. All pots are mulched with 2-3" of shredded pine bark.

I strongly suspect the BER is due to a watering issue as I hand water the pots.

What I was curious about is, since the BER is only affecting the 2nd truss on the plants, does that suggest that around the time the tomatoes on this truss were developing the watering was too inconsistent? and if I keep to my current routine it should be ok since all the other tomatoes seem fine? I am trying to decide what I need to do if anything.

A few weeks back I switched to watering for 30 seconds per pot from 20 seconds per pot. The 30 seconds is enough to thoroughly soak the potting mix and have some water come out the sides of the fabric pots. I increased primarily due to the current weather having highs between 80 and 90F with little rain. I figured 30 seconds from my sprayer is about 7.5L/2 gallons of water (yes, I experimented to determine this). I have all the pots on large plastic collection trays and sometimes there is a bit of excess water, but that is typically gone within the next few hours. It seems like a lot of water given the 1"/sq.ft recommendation (that is about 10 seconds of water from my sprayer). Currently I water every 2-3 days depending on rain/temps. This week it is every 2 days. I water directly onto the mulch in the evenings.

I am just not sure what I should do. Do I continue with 30 seconds of watering? do I switch to 10 seconds and water every day? am I over watering? am I overreacting (probably yes!)?

There is just too much confusing information for new gardeners. I consistently read/hear "water DEEP" and "less frequent"; while at the same time "water consistently and regularly" to avoid BER. Those contradict each other. People also recommend irrigation systems quite often. Those timed systems must also water every day? so that would not be considered 'deep' watering that so many people suggest. Although, perhaps the 'deep' watering is more for in-ground gardens and less applicable to raised beds and pots?

Appreciate and suggestions/comments. Thanks!