Squash blossom end rot is one of those disorders that kind of slaps you in the face. It hurts! One day you are thrilled with the sight of a new squash growing on your plant and the next day you’re greeted with a shriveled, rotted, squishy, squash. I don’t know about you, but there is no room for squishy squash in my garden!

Blossom end rot doesn’t just happen to squash by the way. You can also find this problem creeping up on tomatoes, eggplant, peppers, watermelon and apples. I’m just using squash as an example because that’s what I encountered this morning. The good news about blossom end rot is that it is fixable. Yay! So let’s look at why blossom end rot happens, how it can be prevented and how it can be treated.

What is Blossom End Rot?

Blossom end rot, a physiological disorder not a disease, usually occurs due to one or both of the following two factors. Plants are either allowed to dry out too long between waterings, or plants affected are lacking a sufficient amount of calcium needed to build a stable structure.

Uneven watering. Allowing your garden to dry out too long before watering increase the likelihood of blossom end rot occurring. On the other hand, overwatering can also create problems. Feel your soil, and get on a regular watering schedule, factoring in rainfall. We’ve found most cases of blossom end rot on tomatoes have been caused by plants being allowed to excessively dry out between waterings.

Lack of calcium. When veggie plants lack calcium, their cell structure begins to collapse. The area most affected is usually towards the bottom half of the fruit.

Blossom end rot often presents on a plant’s earliest fruits, possibly before the plant’s root system has been able to really get established. You may first notice a discoloration on the ends of these early fruits that looks kind of like a water stain. As blossom end rot contiunes to develop the discoloration darkens and the fruit becomes misshapen and sunken in.

Treating and Preventing Blossom End Rot

If you’ve found you currently have blossom end rot:

  • Remove the affected vegetables that currently have blossom end rot and begin a regular, consistent watering regime.
  • Treat your plant with a foliar calcium spray, like Fertilome Yield Buster. This can help prevent your next round of squash from developing blossom end rot (as long as you are watering consistently too)
  • Don’t over fertilize. Sometimes we get a little too excited about feeding our plants. Use a low nitrogen fertilizer formula, like FoxFarms Tomato & Vegetable 5-7-3 fertilizer (the “5” is the nitrogen content) and follow the recommendations for application amount and how often to fertilize on the bag. More is not better when it comes to fertilizing. You shouldn’t be trying to force your plants to grow at an unnatural pace.
  • Our heirloom tomato grower, Keith Amelung, advises adding a handful of soft rock phosphate to the holes of vegetables as they are being planted. He doesn’t have issues with blossom end rot so there may be something to this.

One of the quickest remedies, besides watering consistantly, is to treat blossom end rot with a calcium spray.

Good Luck and Good Harvest!

~The Happy Gardener, Lisa Mulroy