How to Stop Blossom End Rot on Potted Tomato

Why did rotten brown spots suddenly appear on my tomatoes? It was late June in USDA garden zone 4. The disease resistant tomato plants from my local garden center had doubled in size and I was thrilled when several tomatoes appeared on the stems. They seemed happy in large pots on my sunny driveway until the rotten brown spots appeared. I had blossom end rot! Read on to find out how to correct the problem.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Disease resistant tomato plants
• Sunny location
• water
• mulch
• potting soil
• fertilizer
• self watering pots

1. 
   tomato plants

   Start with disease resistant tomato plants. Your local garden center can help you pick the best quality plants for your USDA gardening zone. This won't prevent blossom end rot, but will help prevent bacterial, viral, and insect related problems.

2. 
   tomato plants

   Keep your new plants warm! Cool soil and cool night temperatures are hard on tomatoes. Wait a couple of weeks after the last frost date before planting; in garden zone 4 tomatoes need to be protected until around June 1. I purchase my plants in May, put them outside on sunny days, and bring them indoors every night. Think about how warm and humid the greenhouse is compared to the spring weather in your yard and really baby those young plants.

3. 
   self watering pot

   Spend the money on self-watering pots, it will be worth it. These can be found on the internet; check the sources linked at the end of this article. Self watering pots have a well below the soil that can hold up to 4 gallons of water. The plant will draw water as needed during hot dry weather. A lack of soil moisture is the number one reason for blossom end rot.

4. 
   tomato plants

   Plant ONE plant in the 30"L X 15"W X 12" high planter. Some companies suggest you can plant up to three, but that has not been my experience. Read the directions to assemble your pot - some have an overflow cap that needs to be removed. Others have the overflow built in. Use a good quality sterilized potting mix.

5. Add time released fertilizer when you plant - choose a product recommended for tomatoes.

6. Mulch the top to keep the roots cool and slow evaporation of soil moisture. You can use shredded paper bags or newspaper, hay or straw, or purchased mulch like cocoa shells. Paper bio degrades and doesn't get moldy. Wood chips can be used, but they can draw nutrients out of the soil as they decompose.

7. 
   blossom end rot on tomatoes

   Uneven watering is the number one reason for blossom end rot. Tomato plants grow extremely fast in the spring and thrive with even soil moisture - not too soggy and not too dry. The fruits are last in line - roots and leaves will draw available soil moisture first leaving the baby tomatoes to suffer if the soil gets dry. Scientifically, the cells are damaged when calcium in the soil can't draw up into the fruit when water stressed. Your newly planted tomato plant has a very small root system and will need watering from the top until established. Even a few dry hours can cause blossom end rot!

8. Remove any blighted tomatoes. Once blossom end rot develops the fruit will rapidly deteriorate. It doesn't spread, but affected fruits will not be edible and you want to re-direct the plant's growing energy into setting new fruits. Don't fret, blossom end rot is often confined to the first crop when young plants have shallow roots and growth is rapid. Once the roots fill the pot there is less risk if you keep your planter watered.

Tips & Warnings

• Keep an eye on the well, self watering planters can't walk over to the hose to get a drink!
• Ask a neighbor to check your plants if you will be away.
• Use clean potting soil every year to prevent harboring tomato disease or pests.
• Place your pots in a sunny position with good air circulation.
• Keep those new plants warm and watered!
• You can plant a companion plant in the planter such as basil, marigold, nasturtium, pepper, or parsley, but remember additional plants will compete for space and moisture.

Resources

• Tomato Grow Box
• Gardener's supply Company
• How to grow tomatoes in a self watering pot
• How to make dairy free tomato soup
• How to make roasted tomatoes in the oven
• How to make cucumber tomato salad

[wannawrkfrmhome]

on 9/11/2009 I had a lot of tomatoes get this!! I used a couple of those Topsy Turvey upside down planters to try to keep them out of reach from the deer! Those things were impossible to keep watered!! They dried out SO fast and none of the tomatoes got very big. They DID keep them safe from the deer though! I will have to look for those pots - they look neat! 5*

[poshadornment]

on 9/1/2009 Good article and well written. Pls note, cocoa shell mulch is EXTREMELY toxic to dogs and other animals who are drawn to the scent which is like chocolate. not something you want to use. it causes convulsions and death if the animal eats it. I know you are really concerned and conscious about your environment, so thought you'd like to know this.

[mvalora]

on 8/19/2009 You know your stuff!

[showpup]

on 8/8/2009 Thanks for sharing this tomato plant information. I have several in my garden but I also have one on my deck in a large pot that I'm quite proud of. 31 little tomatoes so far! 5 stars

[deepthinkin]

on 7/26/2009 Ah! Even watering is the trick! Thank you!!