GROW: The Book
My green romas look great but the ones ripening are turning black on the bottom of them!! What is this, why is this!!???
Sounds like blossom end rot. It has many different causes, many blame low calcium. I often get it on the first few tomatoes then it gets better. You could try adding pulverized egg shells or even tums into the soil.
If you've got sufficient nutrients in the soil, this can also be caused by inconsistent soil moisture levels (letting the soil get too dry and then watering a bunch at once). Assuming that's the case, keeping the soil consistently moist should alleviate the problem.
There was a great suggestion by @GardenGrub on another thread, quoted below:
"I posted this elsewhere but I had tomatoes that looked exactly like yours in prior years. This year I'm applying calcium water about every other week. Calcium water is equal parts ground egg shells and vinegar. Let sit 1 hour or more than take 1 TBSP of the liquid and mix with a gallon of water. The calcium water is immediately accessible to plants. No blossom end rot this year for me and my tomatoes started to produce fruit earlier."
I tried it this year. After putting the calcium water on the tomatoes only twice this season, I have seen NO blossom end rot at all.
The tomato plants are dying back from verticillium wilt, which happens every summer, but the actual fruit on the plants is superb.
Thanks again for sharing, @GardenGrub !
Thanks for this. I had this problem too and will try it on the next crop of tomatoes. We built a little greenhouse just for them because they were not doing too well. I've been saving eggshells for the last year 😃
Over the years I stopped trying to fight Tomato Plant Blight or Rot or whatever it is that happens towards the end of summer to my tomatoes!
I've come to the conclusion that after the plant gives to me its bounty and has no more to give, that its time is over. Then I choose to focus on other areas of my garden.