Tomato Patch: Tale of two Big Mamas

Kent & his Big Mama tomatoes

Big Mama has failed me again this year.  Like last year, her paste-type fruit is affected by blossom-end rot in disastrous numbers.

If you aren’t sure what blossom-end rot (BER) is, here’s a description from the Plant Diagnostics tab at the University of Maryland Extension’s Home and Garden Information Center: “Blossom-end rot is a common nutritional disorder of tomato, pepper, eggplant, pumpkin, squash and watermelon that is caused by a shortage of calcium in enlarging fruits. Calcium is taken up constantly by plant roots as a dissolved nutrient and travels first to the growing points—new leaves and shoots. Fruits may experience a shortage of calcium if water becomes less available to plant roots (drought).

“This nutritional disorder typically occurs when plants are growing rapidly and the first fruits are developing,” the resource continues. “As fruit cells breakdown due to a lack of calcium, dark blemishes appear on the blossom-end of affected fruits. These may enlarge until the entire bottom of the fruit becomes dark, shrunken and leathery. Factors that encourage BER include low soil pH and low levels of calcium, inconsistent watering, shallow watering or droughty conditions, and excessive use of nitrogen fertilizers. Symptoms are rarely seen in cherry tomatoes and are most often seen in large plum or paste-type tomato cultivars and long pepper fruits.”

My Big Mama tomatoes

When the disease devastated my Big Mama tomatoes last year, Kent Phillips, another Howard County Master Gardener who had given me the plant, surprised me by saying his Big Mamas were producing well and without the disease.  I threw away my diseased tomatoes.  Kent harvested his.

This year I gave Big Mama a second chance and did my best to treat her “right.”  I started a plant from seed Kent gave me.  I made sure the plant had enough calcium when I transplanted it.  I didn’t over fertilize.  I drip irrigated.

Alas, blossom-end rot struck again.  On Friday I picked all of Big Mama’s fruit affected by BER: 30 tomatoes from small green fruits with black ends to larger ones beginning to show pink or red but clearly diseased.  Good fruit: 7. I had lost more than 80% to the disease.

Again I wondered how Kent’s Big Mamas were doing.  I emailed him: “Hi, Kent. I did a fruit count of my Big Mama today: 30 with BER and 7 without, Aghhhh! Tell me again that yours are going well and without BER!”

“Mine are fine,” Kent replied.  “I have 6 plants in and a little bit, maybe 5% of the fruit show some BER. I’m sure that most of the BER is from drought stress since most of it is showing up on the smaller fruits toward the top of the plant.  Obviously, as the plant gets larger, it requires more water.  I’ll have to increase my irrigation of my tomato row from one inch of water per week to two inches.  As for the pH of my soil, it is 7.0 and the calcium level is high at 6654 parts per million.”

My Amish Paste tomatoes don’t have BER

Last winter I had soil samples tested by the University of Delaware Soil Testing Laboratory, and the results for my garden are similar to those of Kent’s.  The pH of the two samples averaged 7.0.  Calcium levels also tested very high, averaging 217 on the 100 index-value scale used by that laboratory.

Do you see the puzzle?  Seeds for Kent’s and my plants came from the same packet.  Both our transplants grew well, and we both drip irrigated regularly, though he has a better system.  Soil tests indicate our plants have sufficient nutrients, pH is the same, and calcium levels are very high.  But Kent has near-zero loss, and I have 80% loss.

I won’t be planting Big Mamas again.  Last winter I researched the idea that sometimes is mentioned in tomato literature, that there are varieties that seem resistant to BER.  I couldn’t find a simple list of resistant varieties, but by tallying observations of other gardeners, I decided to try Amish Paste, a well-known heirloom variety.  I have seven plants growing about 12 feet from the afflicted Big Mama plant.  Not one Amish Paste fruit shows signs of BER.

I welcome your Comment about the blossom-end rot puzzle. Maybe your Comment will help me solve Big Mama’s BER problem.

If you want additional information about BER, CLICK HERE to go to the Plant Diagnostics tab at the University of Maryland Extension website.  Then click on “Discolored All or in Part” and “Blossom End Rot.”

3 Comments on “Tomato Patch: Tale of two Big Mamas

  1. interesting puzzle there. The only possibility you haven't ruled out to explain the difference between Kent's Big Mamas and yours is drainage. Maybe despite the fact that you water similarly his garden has better water retention than yours? In which case your plants could be suffering drought while his are still comfortably moist. Just a thought, hope it helps.


  2. I think Kent's drip-irrigation system is better than mine. His garden is flat, and mine is a series of raised beds on the top of a hillside, so I may have slightly more drainage. My soil has been amended over the years with good leaf/horse-manure compost. Yes, his garden may have a slight advantage. Maybe more water would have helped. You suggestion is oh so logical and I wish I had a way to find the definitive answer to this frustrating problem. Thanks for commenting.


  3. Try adding epson salt and lime. Mine had BER but my daughter added epson salt and hers did not. I prepared containers with the same soil (two year old composted cow manure and hay 50/50 with river sand) and started her plants with mine from seed. I drip irrigate and she hand waters but both had ample moisture.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: