Fix Blossom End Rot In Tomatoes

So you’re starting to get excited about the excellent crop of tomatoes that are coming along nicely. You’re feeling a little bit of pride about your green thumb abilities with this year’s tomatoes and then shock horror, you discover your halfway-developed tomato babies (let’s call them teenagers) are going rotten on the bottom (time to stop the analogy I think)! Been there, done that – hate it. Yes, your juvenile tomatoes have blossom end rot. How are we going to fix it? Read on.

What is Blossom End Rot

Blossom end rot usually occurs early in the season and in half-grown fruit. It appears as an ugly brown to yellow spot on the bottom of the fruit that first appears soft and water-soaked and eventually becomes leathery and black. Blossom end rot (BER) is called many different colloquial terms such as tomato rot (that’s an inventive one), tomato blossom rot, and tomato end rot just to name a few.

What Causes Blossom End Rot

BER is caused by there being insufficient calcium available in the tomato fruit as it is developing. The reasons why this situation can occur are more complicated than you may think. It’s not just the obvious issue of there not being enough calcium in the soil. Most soil does actually have adequate calcium in it, so it comes down to a set of other issues about the plant’s ability to transport adequate calcium to the growing fruit in a timely manner. Key to this is the issue of plant stress. BER can occur from plant stress caused from:

  • too much transpiration in very hot weather
  • fast climbing temperatures over a short period of time
  • inconsistent watering
  • water-logged soil from heavy rain or too much watering
  • feeding too much nitrogen during the early growth phase of the plant resulting in too rapid plant growth

How Not To Fix Blossom End Rot

Yes that’s right. Its important to discuss some of the recommended treatments out there that won’t fix BER, and in some cases can even make it worse. The one that is the biggest bug-bear to me is the idea that Epsom Salts can cure Blossom End Rot. It is just nonsense, and in fact, may make the situation worse by the Magnesium in Epsom Salts competing with the calcium the tomato fruits so desperately needs. So don’t believe those nonsense (but often well-meaning) Pinterest pins telling you that the solution to blossom end rot is a dose of Epsom salts. Save the salts for a good soak in the bath after working hard in the garden to fix your blossom end rot. There are many things in the garden that Epsom Salts are good for , but blossom end rot is not one of them.

In addition, you will often see it recommended that calcium be added to the soil as a way to fix blossom end rot. If your soil is lacking in calcium (unlikely) or is tied up due to soil pH issues, adding addition calcium may help for next years crop, but its not going to help much for this year’s problems.

How To Fix Blossom End Rot

For this reason, you often see it recommended that you should add calcium to the soil or replace the calcium in the plant through a foliar application in order to help correct the problem. But it is actually very rare for soil to be lacking in calcium. Instead, there can be a number of other environmental causes of tomato blossom end rot, from uneven watering due to drought, heavy rainfall or an overcaring gardener. Rapid plant growth, especially if given an overabundance of nitrogen early on, as well as fast climbing temperatures, can contribute to blossom end rot in tomatoes and other susceptible fruits, like peppers, squashand eggplant. Blossom end rot occurs not because the soil lacks calcium but because the plant simply cannot take calcium out of the soil at a fast enough rate to keep up with the growth of the plant or because stress causes the plant to be unable to process the calcium the plant does take up.

How to Stop Tomato Blossom Rot

Unfortunately, this disorder cannot be fully “cured,” as you can’t control nature. That said, tomato blossom end rot can be somewhat alleviated or managed to a certain extent by taking steps to improve or avoid conditions that foster its development – at least those more easily controlled by the gardener, like poor soil, watering and fertilizing. Planting tomatoes in a timely matter and in a well-draining soil amended with organic matter will go a long way in giving the plants exactly what they need to develop healthy growth early on, which means that extra dose of fertilizer isn’t necessary. And if you do fertilize tomatoes, opt for one that is lower in nitrogen and only apply at the recommended rates, or cut by half. Providing adequate and even amounts of water for tomato plants is important too. The addition of mulchcan help retain moisture while keeping the soil and plant roots insulated. While it may or may not be effective, and is a highly debated topic, the addition of crushed eggshells, limestone or calcium carbonate in the soil won’t necessarily hurt, but it may not help much either. All in all, the majority of tomato plant varieties will at some point be affected with blossom end rot. But, in most cases, as the season progresses, this condition will normally clear up on its own without any major ill effects. As for the fruit suffering from tomato blossom end rot, these can simply be picked off and discarded or cut the bad parts out of larger, more ripened ones and eat the rest – it won’t harm you.


I’ve been around farming all of my life. Farmers Life Blog is a way I can share my passion for all things farming and gardening and hopefully share some of my knowledge and experience through the process. Shootin' the breeze doesn't have to be confined to the front porch anymore, now there's a whole world to share my deep and abiding love with.

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