Updated date:

How to Prevent Blossom-End Rot in Tomatoes (2 Easy Methods)

Lynn has been a professional organic farmer for the last 35 years and runs a 210-acre farm in Western Colorado with her husband.

It's heartbreaking to grow a tomato plant only to have the fruit rot before it's even been picked. Luckily, blossom-end rot is an easy problem to fix.

It's heartbreaking to grow a tomato plant only to have the fruit rot before it's even been picked. Luckily, blossom-end rot is an easy problem to fix.

Help! My Tomatoes Are Rotting on the Vine!

Tomatoes are the #1 garden vegetable, and for good reason—most everyone loves them. But it's no fun to grow them if the ends start to rot while the tomatoes are still hanging on the vine. It is so heartbreaking to grow a tomato plant only to have the fruit rot on the vine before it's even ready to pick.

We used to have a terrible time with blossom-end rot until we started using a foliar calcium spray. Now we hardly ever see blossom-end rot on our tomatoes, and if we do, we just up the calcium and the problem goes away. No more rotten tomatoes! But there's another easy way to prevent this issue. In this article, I'll describe both methods.

2 Easy Ways to Prevent Blossom-End Rot

Depending on the pH of your soil, there are a couple of different methods for preventing your tomatoes from rotting. (If you haven't done so already, here's how to check your soil's pH with baking soda and white vinegar.)

1. Add Epsom Salt to the Soil

Some people use Epsom salts, 1 tablespoon per plant in the soil, to cure this problem. Calcium and magnesium have a direct relationship in the soil, so adding magnesium can free up the calcium locked up in the soil.

If your soil pH is below 6.5, Epsom salts should work for you. Our water runs with a pH of around 8, so we are not able to get the calcium unbound from the other elements in the soil.

2. Use Foliar Calcium Spray

If your soil pH is too above 6.5, you'll need to get the calcium into the plant through the leaves. Luckily, it's very easy and effective. When we switched to a foliar spray of calcium, the blossom-end rot problem went away.

You can't fix a tomato that has rotted cells or dead cells, but you can prevent it from happening on the next tomatoes that are starting to form. We also use the foliar spray to keep the lettuce tips from burning, another problem that happens when the calcium is locked up in the soil.

If you want to try a foliar calcium spray on your tomato plant, you'll find many companies online that make the stuff. You can also find it in most garden shops. I recommend looking for an organic one.

DIY Calcium Spray Recipe

If you don't feel like buying calcium spray, you can also make your own at home.

  1. Bring the shells from 20 eggs to a boil in one gallon of water.
  2. Remove from heat.
  3. Let mixture sit for 24 hours.
  4. Strain the liquid and add it to a sprayer.
  5. Spray it on your plant once per week.

Note: Do not mix any other nutrients or pesticides in the mix. The calcium will bind with anything that you put in the sprayer, so if you mix anything else in, the calcium won't be absorbed by the plant.

When to Use Foliar Calcium Spray

The leaves on your tomato plants will be receptive to absorbing the calcium when the air temperature is above 70˚F (21˚C). Spray the calcium on once a week when temperatures are in that range. If your tomatoes are still getting blossom end rot, then spray twice a week.

A good tomato is well worth the time and effort it takes to grow!

A good tomato is well worth the time and effort it takes to grow!

Good Luck With Your Tomatoes!

Tomatoes may take a few extra steps to get a bountiful harvest, but they are so worth it. So get your calcium and give your plants a weekly spray. And now that you've got your blossom-end rot under control, check out my tips for getting the highest yield and best flavor from your tomatoes!

May your garden be easy, fun, productive, and always organic.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Lynn Gillespie

Related Articles