Sunday, June 21, 2009

Kick Blossom-End Rot's Ass!


Blossom-end rot is physiological condition caused by calcium deficiency in the blossom end of the fruit. It occurs most notably in tomatoes, but also occurs in peppers, squash, watermelon and any other fruiting vegetable. It is characterized by the decay of fruits at their blossom end; appearing as a dry brown spot about the size of a dime, that may blacken and sink in as it grows to about the size of a half dollar. This disorder is most severe following extremes of over or under-watering.

There are steps that can be taken to greatly reduce this condition:

  1. Lime soils to a pH of 6.5 to 6.7 before planting. Gardens not limed within the past 2-3 years will need 2 cups of lime per plant. The lime should be worked in to a depth of 12 inches.
  2. Fertilize properly. Applying too much fertilizer at a time can result in blossom-end rot. Following soil test recommendations is the best way to ensure proper fertilization. Terracycle makes a Tomato Plant Food based in worm poop that has a calcium boost. I have found it to be very effective.
  3. Mulch plants. Use straw, pine straw, decomposed sawdust, plastic or newspapers. Mulches conserve moisture and reduces blossom-end rot.
  4. Water when necessary. Tomato plants need 1-1.5 inches of water per week during fruiting. Extreme fluctuations in soil moisture can increase blossom-end rot.
  5. Spray calcium. Plants may be sprayed with a calcium solution at the rate of 4 level Tbs of calcium nitrate or calcium chloride per gallon of water. The spray should be applied 2-3 times per week, beginning when the second fruit clusters bloom. Several foliar sprays containing calcium are available and all work well for tomatoes. Calcium chloride is only suggested for tomatoes.
  6. Quick fixes. Foliar application of a weak Epsom Salt (magnesium) solution can effect calcium uptake. Other suggestions include powdered milk, crushed egg shell tea, bone meal tea, Tums tablets, etc., but prevention is the key. Removing affected fruit is also recommended to reduce stress on the plant. "Gardens Alive" sells a product called Rot-StopT Spray that can be applied to plants weekly to supplement calcium reserves and prevent rotting.
Now let's go and kick some ass!

20 comments:

islandgardener said...

I had this one time only with my San Marzano tomatoes -- and you know I grow quite a few. It was weird. And, with yellow squash, but not with zucchini, grown the same year in the same plot.

I was wondering...the geese have finished laying eggs for the season (they only lay half a year, unlike chickens), and I have crushed oyster shells which I give them to boost their calcium to keeps shells hard. I wonder if I sprinkle just a bit around each, would it be a good preventative???

Alexandria Sewell said...

islandgardener, I have heard of using crushed oyster shells to provide calcium before, but it needs a way to get down to the roots. So, perhaps if you worked it into the soil a bit around the roots.

Josie said...

ohhh well timed post. we are dealing with some tomatoes with blossom rot- thanks for the info.

Alexandria Sewell said...

Thanks Josie and you're welcome. I'm glad someone could use the information.

Tatyana said...

Hi Alexandria and thank you for this post! Very good information!

Alexandria Sewell said...

Thanks for dropping by the blog again, Taty. I'm an information fiend. More to come!

AR said...

Just to pipe up on the San Marzanos, paste varieties (Roma, plum) seem the most susceptible. I lost every single paste tomato last year (Big Mama hybrid), but all the other varieties were fine. I followed the same watering schedule on all of them.

Your tips are very helpful. I find just watering regularly (or when soil gets dry) works well for me.

Alexandria Sewell said...

Thanks for the added info, AR. I hadn't though of certain varieties being more susceptible than others.

K Dilley said...

Such a great user friendly post, thanks!

Alexandria Sewell said...

K Dilley, thank you for the compliment! I try to make all of my posts with lots of information user-friendly.

JGH said...

I really appreciate these tips, because I have been afflicted with this syndrome in the past - so far none this year but it's still early. Now I feel prepared!

Patrick said...

I had this a couple years ago and added a calcium supplement to the soil the next spring. I also water twice a week as a rule, now. Consistency is apparently helpful. Blossom end rot is sooooo dissapointing!

Alexandria Sewell said...

JGH, I'm glad that the tips were helpful. I've been lucky so far this year, too. However, the calcium in my tomato fertilizer makes me feel pretty prepared as my crops further in development.

Alexandria Sewell said...

Patrick, it sounds like you've learned from experience. I would hate to have babied my tomatoes so long just to have them succumb to something preventable. I water at least twice a week, depending on rainfall.

Bucolic Bushwick said...

This is great info, thanks for sharing.

Alexandria Sewell said...

Bucolic, no problem. Thanks for stopping by.

sharp green pencil said...

Hi there Alexandria.. thanks for your comment on the blog. I too love the crows.. and your carnivorous plants are great! I saw some wonderful ones in London when was back. I have no garden but maybe I can encourage one on the balcony here in Orlando!

Alexandria Sewell said...

sharp green pencil, thanks for stopping by my blog and checking out the short list of carnivorous plants in my collection. I would DEFINITELY encourage you to try some gardening on your balcony. You will be surprised at what you can grow in containers in a small space.

joey said...

Thanks for sharing this informative info ...

Alexandria Sewell said...

My pleasure, Joey. I hope you got something out of it. Thanks for stopping by my blog.

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