I’ve been having a blossom end rot problem with my Summer Squash. After reading a bit about the disease, I found a couple of solutions to try.
Vegetables will begin to grow and look fine, but then the ends will turn brown and rot the fruit like in my image below.
First, overwatering is a concern. Because it tends to be very hot here, I do water my garden every morning. Plants in pots outdoors, like my Persian Lime Tree, need lots of water.
The problem with too much water on the yellow squash, or zucchini which is similar, is that calcium leaches out of the soil and the plant can’t get enough to grow the squash correctly.
So adding calcium can help. I decided to try adding eggshells, but store bought organic calcium may be the better way to go. It’s not cheap, but this problem can affect many types of vegetables so the bag would probably come in handy.
I have read that one way to add calcium to garden dirt is by adding crushed, dried eggshells.
A mortar and pestle can be used to crush the shells to make a fine powder. This can be added to the soil. However, I also found this page at the Garden Myths site which claims that eggshells basically do very little to enhance soil. They say that grinding the shells to powder and adding to acidic soil is your best shot for this idea to work. They claim that eggshells remain intact for long periods of time and do not break down to add nutrients to the soil.
In the end, what the suffering plants probably need is additional calcium (in whatever form you choose to use) and possibly less water. Read more about Blossom End Rot at the Gardeners site.