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Tomatoes: Blossom End Rot

I think just about every gardener in the Rogue Valley has battled with blossom end rot on their tomatoes at one time or another. It’s really irritating to find those water-soaked spots on the ends of the fruits that you’ve nurtured through frosts and heat and hornworm attacks.

Preventing blossom end rot in tomatoes-slide0
Open Stock Resources
Avoiding blossom end rot
Open Stock Resources

That spot at the blossom end of your tomatoes is the classic sign of blossom-end rot. This fairly common problem is not truly a disease, but a calcium deficiency with the plant. It can occur in a wide variety of garden favorites, from peppers to squash, and even cucurbits like cucumbers melons.

Blossom-end rot is common when the growing season starts out wet and grows drier when fruit is setting. Damage appears when fruits are about half their full size. The rotten areas appear and turn dark brown fairly quickly. These areas will begin to rot, so fruits should be removed and discarded.

There are a number of elements that can cause issues with a plant’s ability to assimilate correct amounts of calcium for good fruit development. These include: soil that is too wet or too dry, too much nitrogen, damage to the root system, soil pH that is out of kilter, cold soil and chemical imbalances in your soil – primarily too much salt. If you are using a product like Miracle Grow, you could be adding unwanted salts into your soil as residue.

Consistent moisture through the growing season is vital to avoiding this most annoying of maladies. When the weather is dry, water thoroughly twice weekly to a depth of at least 6 inches.

Some additional keys to avoiding blossom end rot are:

  1. Make sure your soil is warm before you plant.
  2. Soil pH should be 6.5 or thereabouts.
  3. Use balanced organic fertilizers lower in available nitrogen and higher in available phosphorous.
  4. Mulch to maintain soil moisture and keep down the weeds.
  5. Keep a garden journal; some varieties are more susceptible than others.

There is one other element that the old-timers tell me is a sure-fire way to stop and/or prevent blossom end rot. This would be several applications of Epsom salt.

To utilize Epsom salt as a preventative, get it worked into the soil before you plant. Use about a pound of Epsom Salt to a 4’ x 8’ area; about the size of a standard raised bed. The Epsom Salt will then be easy-to-utilize source of calcium and magnesium for your plants.

Epsom Salt also encourages strong root systems and growth as well as strong development for all of your garden veggies. Consider working it into the soil along with your compost before you plant your beds. A side dressing of Epsom Salt a couple of times during the growing season will keep your plants healthy and strong. Be careful not to allow the Epsom Salt to touch the leaves or stems of your plants.

If blossom end rot attacks your tomato plants, you can totally stop it and your plants can still go on to produce healthy tomatoes. At the first signs of blossom end rot, pluck all of the fruits exhibiting symptoms and get rid of them. Water the tomato plant with an Epsom Salt mixture of ½ a cup in a gallon of water once weekly. Apply the entire gallon around the base of the plant. The Epsom Salt mixture will be instantly available to the root system to start correcting the issue, and stop future fruits from being destroyed by blossom end rot.

Good luck with your tomatoes this year. Now get out there and plant something!