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Curbing Blossom End Rot

A healthy Calliope eggplant puts on new fruit after blossom end rot damaged fruit were removed.

Blossom end rot can be an incredibly frustrating challenge for any vegetable gardener.  There is something particularly upsetting about watching a perfectly healthy-looking plant produce damaged and rotten fruits!  Fortunately, blossom end rot can be avoided and, once in process can often be overcome.  Blossom end rot can occur on a range of fruits, but is most commonly seen on tomatoes, peppers and eggplant.  

If you are a vigilant gardener (as you should be), keeping a watchful eye on your crops through their development, you will notice the advent of blossom end rot as soft, bruised areas on (or near) the bottom tip of your fruit.  This dark, squishy area will develop into a black, crusty scar at the bottom of the fruit, eventually leading to a shriveled and moldy mess.  

Blossom end rot is the result of a lack of calcium in the fruit tissue.  This calcium deficiency can be caused by a lack of calcium in the soil or by the plant’s inability to effectively absorb calcium from the soil.  Here are a few simple ways to prevent and/or reduce the impact of blossom end rot in the garden (most of these things you should be doing anyways!):

  1. Check the pH of your soil.  Proper pH range for most fruiting vegetables is between 6.3 and 6.9.  Maintaining the proper pH will help crops absorb nutrients from the soil.

  2. Maintain even watering cycles through the season.  Most often, blossom end rot is a result of water stress which disrupts the plant’s ability to draw calcium up from the soil.  Keeping the soil adequately and consistently moist can eliminate this problem.

  3. Add bone meal to your soil.  Bone meal, known primarily for its supply of phosphorus, but also supplies calcium.  Bone meal feeding supplements are a long-used tool to prevent blossom end rot in long-season fruiting crops.

  4. Add dolomitic lime. Dolomite lime supplies both magnesium and calcium to the soil (in addition to adjusting soil pH).  If used in high doses or too frequently, it can lead to nutrient imbalances in the soil, but it can also be highly effective in supplying fruiting crops with adequate calcium to support healthy fruit production.

If you plan to add organic amendments like bone meal and dolomite lime to the soil every season, be sure to take soil samples regularly to guard against nutrient imbalances and over fertilization (which can lead to their own set of crop health issues).  

Blossom end rot on tomatoes: 

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