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Blossom End Rot On Peppers

Blossom end rot can be disheartening to see in your garden. You’ve worked all season long to take care of your plants, only to see the fruits turning brown and mushy on the ends.

Thankfully, you can take some measures to help your plants recover and produce healthy fruits going forward. Dealing with blossom end rot on pepper plants starts with understanding the root cause.

Blossom End Rot Bell Pepper
Blossom end rot on bell pepper.

What Causes Blossom End Rot?

Dark spots on the bottom or sides of peppers are caused by blossom end rot. This condition develops due to a calcium imbalance in the plant. Despite the name, it is not actually rot, but rather a result of the plant’s inability to produce healthy skin on the fruits.

When calcium in your plants cannot effectively reach the developing fruits, tomatoes and peppers cannot form a healthy skin, leading to blossom end rot. These dark brown, black, or gray patches usually form at the bottom of the fruits. It is most common in the early season when weather is cooler and moisture fluctuations are high.

Blossom End Rot Pepper Pod
Blossom end rot on sweet pepper.

Blossom end rot begins at the blossom side (or the bottom) of the fruit because that is where newer skin forms as the vegetables grow. Despite the problem being a calcium deficiency in the plant, your soil probably doesn’t need more calcium.

It is more likely that your plant is having trouble accessing and providing calcium to the developing fruit on a constant basis. This makes the solution to the problem a bit more tricky. However, the sooner you start taking action the more likely it is that your plants will recover.


How To Prevent Blossom End Rot

The best way to deal with blossom end rot is to do your best to prevent it from starting. There are many helpful studies and guides explaining the best way to get rid of the issue, but if you follow these guidelines, you will have the best chance of keeping it from ever happening.

  1. Don’t overwater. The most common cause of blossom end rot is overwatering. It is exciting to get outside and tend to your garden, I know! But watering too much is not good, especially where drainage is poor. If you soak your plants, especially just after a drought, they can become stressed by the excess moisture and develop blossom end rot. Over-watering can also cause cracking in tomatoes. Keep your soil moist but well-drained.
  2. Don’t underwater. Okay, I know, this is annoying. However, one of the best ways to keep your plants from stressing is to water evenly. Never allow your peppers or tomatoes to become overly dried out. Try using mulch on the surface of the soil to help reduce evaporation and to promote an even soil moisture. Use a moisture level reader if you have a larger garden, as some areas can become more dry than others.
  3. Use the right fertilizer. Using a fertilizer that contains the proper balance of nutrients will save you a lot of headaches. Be sure to read the ingredients in your fertilizer before buying to make sure it has a good balance of essential nutrients, including calcium and magnesium.
  4. Prune excess foliage. Calcium moves through your plants in one direction – from the roots, through the xylem, and to the leaves and fruits. It cannot move in the other direction (through the phloem). When it is hot, or the relative humidity is low, the leaves demand more of the available water for transpiration. This means that much of the calcium coming up through the roots will bypass the developing fruits, and will be lost to transpiration. To reduce this, you can prune away excess foliage (older leaves, leaf branches on tomatoes) periodically. This forces more of the calcium-containing water to travel to the fruits.
  5. Add a handful of bone meal. If you are growing in containers, I recommend adding supplemental calcium at the time of transplanting. Work some bone meal into the planting hole just before transplanting. This will slowly break down over the course of the year, releasing calcium to your potted peppers..
  6. Test for pH. If you have a raised bed or in-ground garden, it is worthwhile to test your soil pH every 1-2 years. Depending on what you plan to grow, you can use soil additives to ensure optimal nutrient levels. A mail-in soil test is ideal for accurate results, and will also tell you the calcium and magnesium content in your soil for added certainty. Generally, peppers and tomatoes grow best in slightly acidic soil (between 6.0-7.0). You can increase pH with lime or limestone, and decrease pH with sulfur. Be sure to wait 3 months after using additives, and test pH again before adding more.
  7. Choose better varieties. Through crossbreeding, peppers and tomatoes have been hybridized to avoid common issues during growth. Some have increased resistance to water stress, and are thus less likely to develop blossom end rot. Read through the description of your plant varieties before choosing which to grow in your garden.
Blossom end rot on banana pepper
Blossom end rot on banana pepper.

Over time, your gardening routine will become second nature. These techniques will be your best bet to avoid blossom end rot on pepper plants and tomatoes.

However, following these measures will also help prevent a host of other common pepper issues, and will lead to overall healthier plants.


Blossom End Rot Treatment

When you notice your peppers or tomatoes starting to form dark spots on their bottom ends, you should take action as soon as possible. The longer you wait to fix a blossom end rot issue, the less likely that you will end up with a healthy harvest during this growing season.

Blossom End Rot Pimiento Pepper
Blossom end rot on pimiento pepper.

However, it is possible to restore your plants to good health. In order to cure blossom end rot, you must ensure the plants are taking in the nutrients in the soil. Try these tips:

1. Prune excess foliage

As we have established, blossom end rot has more to do with calcium delivery than its availability in the soil. So, rather than add calcium to your soil, we have to make it available to the fruits as they develop.

One method to try is pruning excess leafy growth from your pepper and tomato plants. Foliage is demanding for transpiring water under hot and dry conditions. Excess heat and low humidity mean more water loss via the leaves.

Tip: This technique is also helpful in providing good aeration for your plants (especially tomatoes), reducing the likelihood of some diseases.

By pruning some of the foliage from your plants on a regular basis, the overall number of leaves is reduced, and thus more of the water can be used to produce healthy fruits.

2. Keep soil moisture even (don’t overwater)

Soil moisture levels can dictate the overall health of your plants. If your plants go on a roller coaster ride of being extremely dried out, to soaked, and back to dry again, they will be stressed. Here are a few methods to achieve more even soil moisture:

  • Increase organic matter in the soil. Compost and other rotted organic materials add good bacteria to the soil, which can help reduce wide fluctuations in moisture content. Don’t add too much, just amend the soil at the beginning of each season to keep the soil alive and healthy. This can also help improve drainage for clay-heavy soils.
  • Mulch at base of plants. Add a thick layer of mulch (shredded leaves, straw, or dried grass clippings) around the bottom of your plants to decrease soil evaporation and to keep roots cool during a heatwave.
  • Water only when needed. Get into the habit of checking the soil before you water. If you feel moisture an inch or two below the surface, your plants likely don’t need a drink. On the other side, don’t wait for your plants to droop their leaves before watering. Keep the soil consistently moist.
Mulched pepper plant
Thick straw mulch layer around base of pepper plant.

3. Remove affected fruits immediately

Once you spot a pepper that has blossom end rot, remove it from the plant. Since the pepper is already compromised, there is no reason to let the plant continue wasting its energy to finish growing the fruit.

After removing peppers with BER, the plant will send its energy towards the other fruits. It will also have more bandwidth to grow new flowers and additional fruits, leading to a better overall harvest of healthy peppers.

4. Help plants absorb calcium

Blossom end rot is caused by a lack of calcium reaching the developing fruits, but that does not necessarily mean that your soil needs added calcium. The issue with adding calcium is that too much can also be a bad thing.

In order to help remedy this, follow our steps for preventing blossom end rot (above) on an ongoing basis. This includes things like consistent watering, planting stronger varieties, and fertilizing as needed.


Can You Eat Peppers with Blossom End Rot?

While fruits with blossom end rot may appear to be ruined, it is usually safe to cut away the affected areas of the fruit and eat the rest. However, blossom end rot can invite the growth of mold where the fruits are damaged, so look closely for signs of mold.

If you see any fuzzy mold, especially in any color other than white, it may be best to avoid eating the fruits entirely. However, blossom end rot alone does not mean you have to throw away your veggies.


I hope this helps you take care of your blossom end rot on pepper plants. By keeping your soil healthy and following our tips, you’ll save yourself a lot of stress.

Calvin Thumbnail

Calvin

One of the original Pepper Geeks! When Calvin isn’t gardening or learning more about peppers and botany, he might be traveling new places or playing some music.

HSHS

Wednesday 16th of August 2023

When people say "water evenly" does that mean even over space or time? I.E. should soil be the same moisture around all the roots, top to bottom, or should the plant to get a predictable amount of water over a steady schedule? (In terms of avoiding blossom end rot.)

Omar Abdoun

Tuesday 17th of August 2021

Hey I really love your channel- it’s been really useful in learning how to grow pepper plants. I was wondering if you had any advice troubleshooting the blossom end rot I’ve been getting primarily on a giant Marconi pepper plant We have planted in a 3 gallon pot. From what I can tell it is pretty prolific and I have at least 10-12 big peppers on the plant at a given time (I’ve been picking any that get BER in hopes that the energy and nutrients are better spent on the healthy peppers). Here’s what I’ve tried so far: I added sea bird guano to the soil at the beginning of the season. I’ve also been fertilizing with miracle grow tomato and vegetable fertilizer according their instructions. I had a bit of an overwatering problem at the beginning of the season so I scaled back the watering. Once I started getting peppers every single one has gotten BER. I fertilized with tums in water to add calcium a few times in case there was a calcium deficiency and that didn’t do anything. Increased the water slightly and that didn’t do anything either. So far I’ve picked about 10 peppers from this plant and every single one had BER. I have 12 more on the plant now and almost every one has BER as well. Do you guys have any tips on where I can go from here? I’m in zone 7b for reference. Thanks a lot in advance!!

peppergeek

Wednesday 18th of August 2021

Hm, well I doubt your soil requires calcium at this point, so no need to try calmag or anything like that. I am guess it is still a watering issue - do you have your plants mulched? Use straw or woodchips to keep water retained for longer in the soil and avoid quickly drying out after watering. Try to avoid the extremes of very wet and very dry days. Only water when necessary! If it is cool and cloudy, don't water as often as when it is hot and sunny. Hope this helps.