Effective Cures for Blossom End Rot on Tomatoes and Other Vegetables

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Robby

Many commercial growers and home gardeners often confront the issue of Blossom End Rot (BER) in their tomato, pepper, and eggplant. The BER is a physiological disorder caused by a localized calcium deficiency in the blossom-end of the fruit. It is a physiological disorder and is not caused by fungi, bacteria, or any other living disease microorganisms. Also, BER could also be seen on non-solanaceous crops such as pumpkins, squash, and watermelons.

Symptoms of BER first appear as light-tan, water-soaked lesions, usually on the distal end of the fruit but in the case of peppers, on the side of the fruit as well (Figure 1 and Figure 2). The lesions then enlarge and become black and could become leathery. In tomato, as BER advances, fruits might develop internal black lesions. Growers should not confuse between BER and sunscald as both symptoms could look alike. With respect to sunscald, it typically appears on the side of the fruit that is exposed to the sun, while blossom end rot can occur on unexposed fruit surfaces, and always at the blossom end.

Blossom end rot is a frustrating disorder that can plague tomatoes, peppers, eggplants, and other fruiting vegetables. This condition causes the bottom of the fruit to become discolored and sunken. While unsightly, blossom end rot does not actually involve any rot organisms like fungi or bacteria. Instead, it is caused by a calcium deficiency in the plant.

Calcium is vital for the proper formation of cell walls in fruits. When calcium levels are insufficient during fruit development, the cells break down, leading to the characteristic lesions of blossom end rot. Though you cannot reverse the damage on affected fruit, preventing further issues is possible through proper cultural practices and soil amendments.

What Causes Blossom End Rot?

There are a few key reasons why your plants may not be getting enough calcium:

  • Inconsistent watering – Erratic watering causes fluctuations in soil moisture which reduces calcium uptake. This is the most common cause of blossom end rot.

  • Low soil calcium – Continual crops grown in the same soil can deplete calcium over time. Have your soil tested to determine if this is the case

  • Improper pH – A pH below 65 or above 7.5 will limit calcium availability Test soil pH and amend as needed.

  • Root damage – Cultivating too close to plants, transplant shock, and other root injuries affect nutrient absorption. Handle plants carefully.

  • Over-fertilization – Too much nitrogen stimulates rapid growth, increasing the demand for calcium. Use a balanced fertilizer program.

Effective Treatments to Cure Blossom End Rot

While you cannot reverse blossom end rot once it develops on a fruit, you can take steps to prevent it from affecting more produce. Here are the most effective treatments:

1. Consistent Soil Moisture

Erratic watering is the number one cause of blossom end rot. Tomato plants and other vegetables need about 1-2 inches of water per week. Use drip irrigation, mulch, or other methods to maintain optimal soil moisture.

2. Add Organic Calcium Sources

If soil tests confirm low calcium levels, add calcium amendments such as:

  • Crushed eggshells
  • Bone meal
  • Calcium nitrate
  • Lime
  • Gypsum

Work amendments into the soil before planting. Re-test soil pH after adding calcium to keep it in the ideal vegetable growing range.

3. Choose Calcium-Rich Fertilizers

Instead of typical nitrogen-phosphorus-potassium formulas, look for tomato fertilizers that also contain calcium. Apply according to label directions during fruiting.

4. Use Preventative Foliar Sprays

Applying calcium directly to plant leaves provides rapid absorption. Spray a calcium solution weekly once fruits start to develop.

  • Calcium chloride – 1 tbsp per gallon of water
  • Calcium nitrate – 1-2 tbsp per gallon of water

5. Allow Fruits to Fully Ripen

Immature green fruits are more prone to blossom end rot. Leave fruits on the vine longer to allow them to fully ripen and strengthen cell walls.

6. Consider Variety Selection

Some tomato varieties are more susceptible to blossom end rot than others. Talk to your local nursery about resistant options to try in the future.

7. Check Soil pH

Have your soil tested to determine pH. Vegetables grow best in slightly acidic conditions, between 6.5-7.0. If pH is off, amend soil with lime (to raise) or sulfur (to lower).

When to Treat Blossom End Rot

Be proactive to nip calcium issues in the bud. Take these steps:

  • Before planting – Test and amend soil as needed. Incorporate calcium sources and set up irrigation.

  • During growth – Avoid root damage from cultivation. Maintain even soil moisture.

  • Early fruit set – Begin weekly foliar calcium sprays. Apply calcium-rich fertilizer.

  • Throughout season – Monitor soil moisture and re-apply calcium spray after heavy rains.

Catching deficiencies early gives you the best chance of preventing blossom end rot all season long. While you may lose some early fruit, your efforts will pay off in bountiful, beautiful harvests.

Home Remedies for Blossom End Rot

Gardeners have come up with various home remedies to provide an immediate calcium boost when blossom end rot strikes:

  • Antacid tablets – Crush calcium-based antacids and dissolve in water. Pour around plant roots.

  • Milk – Spray a 1:1 milk and water solution onto affected plants. The calcium in milk offers rapid relief.

  • Wood ashes – Sprinkling wood ash provides potassium and calcium. Use in moderation to avoid salt buildup.

  • Bone meal – Work bone meal into soil around plants. It provides a readily available calcium source.

  • Borax – Mix 1 tsp borax with 1 gallon of water and spray plants. Use this remedy occasionally.

These quick home treatments may help rescue plants after symptoms appear. However, correcting underlying issues with soil pH, fertility, and watering will provide the best results.

When to Remove Affected Fruit

Blossom end rot only affects the flower-end tip of the fruit. If the damaged area is minor, you can trim it away and eat the remainder of the tomato or pepper. However, severely affected fruit or those with lesions covering more than 25% of their surface should be removed and discarded.

Removing damaged fruit:

  • Prevents rot organisms from moving in

  • Allows the plant to direct energy towards new healthy fruit

  • Reduces sources of disease inoculum

Promptly picking off and throwing out severely affected fruits limits further issues. Just be sure to follow cultural prevention methods to address the underlying calcium deficiency.

Does Blossom End Rot Affect Food Safety?

While blossom end rot damages fruit quality and productivity, it does not make the produce unsafe to eat. The affected tissue is limited to the flower-end of the fruit, leaving the remaining upper portion edible.

The lesions do not involve any pathogenic fungus or bacteria. Simply trim off any discolored areas on mildly affected fruit. The remainder can be eaten fresh or cooked into sauces with full confidence of safety.

cures for blossom end rot

What causes Blossom End Rot Image

In the case of BER, due to lack of calcium, fruit tissue at the blossom end collapses,

turning dark in color. Calcium moves into the plant from the soil with water. Since the blossom end of the fruit is the farthest where calcium accumulation takes place, larger fruits and longer fruits seem to be most susceptible. In fruits, calcium deficiency during early rapid cell division phase carries over as the fruit expands and leads to BER symptoms in fully formed fruit (Figure 3). Research results suggest that signs of blossom end rot on fruits become visible two weeks after the calcium deficiency has occurred.

Calcium is taken up by the plant as a divalent cation (Ca+2). Calcium present on soil particles first moves into soil solution and then taken up by plant roots by diffusion and mass flow. Within the plant root calcium moves into the xylem (water conducting vessels). For calcium to be continuously absorbed and for its movement through the xylem, there need to be continuous movement of water into and up through the plant. It also requires a continuous supply of calcium from the soil. Most soils in Iowa have sufficient calcium through liming applications to support proper plant growth, however we still observe BER. The primary reason we still observe BER is because of inadequate movement of calcium into plants. Factors that influence root and plant growth can significantly impact calcium movement. Some of the examples include improper irrigation, factors affecting root growth such as saturated soils (low oxygen limits root function), root pathogens, soil compaction, soil temperature and soil pH. Calcium availability decreases when soil pH starts trending below 6.0. High root zone temperatures, especially when we use black plastic mulch can also limit root growth and Calcium uptake. There is also an internal competition for calcium within the plant. Since transpiration occurs through leaves, generally there is more calcium there as compared to fruits, which have a much lower transpiration rate.

Timing and proper amount of water should be provided to plants to ensure a continued supply of calcium. Longer irrigation intervals reduce water uptake and may lead to wilting of plants that can severely restrict calcium uptake.

How To Stop Blossom End Rot On Tomatoes |5 Simple Tips|

FAQ

How to quickly fix blossom end rot?

How to Fix Blossom End Rot. Unfortunately, once a tomato develops blossom end rot, you can’t reverse it. However, the problem isn’t contagious and won’t spread to other plants or fruit. Just remove the damaged tomatoes as soon as you detect a problem.

What can I spray on tomatoes for blossom end rot?

Rot-Stop can be used both indoors and outdoors on listed plants.
  • Correct calcium deficiency to control blossom end rot on tomatoes with Rot-Stop tomato blossom end rot ready-to-use spray from Bonide.
  • Garden fertilizer uses nutritional calcium derived from calcium chloride as the main active ingredient.

What is the chemical treatment for blossom end rot?

How To Prevent & Control Blossom End Rot: Maintain soil pH around 6.5. Use sulfur or lime to lower and raise soil pH respectively.

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