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Blossom End Rot On Pepper and Tomato Plants

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 means understanding the cause and planning ahead.

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

What Causes Black Bottom on Peppers?

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

When the calcium in your plant is inaccessible during fruit production, the tomatoes and peppers cannot effectively produce new skin. This causes dark brown, black or gray patches, usually at the blossom end of each fruit. 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 over-water. It is common for casual gardeners to over-water their plants. It is exciting to get outside and tend to your garden, I know! But watering too much can be catastrophic in a number of ways. If you soak your plants, 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 under-water. 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 avoid soil 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. Also, once your plant is producing fruits, try to reduce the amount of nitrogen. This element encourages more leafy growth, and can cause decreased yields.
  4. Prune excess foliage. Calcium moves through your plants in one direction – from the roots through the xylem 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 the 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 crushed eggshells. Though calcium-deficient soil is unlikely the cause, you it can’t hurt to ensure that there is enough. If you are planting in the ground, work some finely-crushed eggshells into the soil before planting each year. Eggshells contain calcium and can help ensure that your soil is rich in this vital element, helping prevent blossom end rot.
  6. Test for pH. If you have a raised bed or in-ground garden, it is worthwhile to test your soil pH before planting every 1-2 years. Depending on what you plan to grow, you can use soil additives to ensure optimal nutrient levels. Use a cheap meter to test your pH level, and reference this guide to find out the optimal soil pH level for a variety of common plants. Generally, peppers and tomatoes grow best in slightly acidic soil (betweel 6-7). 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 hardy plant varieties. Through plant breeding, 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.

Over time, your gardening routine will become second nature. These methods 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 healthier plants.


How To Cure Blossom End Rot

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

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

Prune excess foliage

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

One method to try is pruning excess leafy growth from peppers and tomatoes. Foliage is demanding for transpiring water under stressful conditions. Excess heat and low humidity mean higher transpiration.

Tip: This technique is also helpful in providing good aeration for your plants, reducing the likelihood of some disease.

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

Keep soil moisture even

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

  • Increase organic content of soil. Compost or other organic material adds good bacteria to the soil, which can help reduce wide fluctuations in moisture content. Don’t add too much, just amend at the beginning of each season to keep the soil alive and healthy.
  • Mulch at base of plants. Add a thick layer of mulch (straw or grass clippings) around the bottom of your plants to decrease soil evaporation and to keep roots cool during a heatwave.
Mulched pepper plant
Thick straw mulch layer around base of pepper plant.

Help plants take in more calcium

Blossom end rot is caused by a lack of calcium in the plants, but that does not necessarily mean that your soil doesn’t have the calcium required. The issue with adding calcium is that the soil may not need calcium, but rather the plants need help using the calcium.

In order to help remedy this, follow our steps for preventing blossom end rot on an ongoing basis. This includes things like consistent watering and rotating your crops.


Can You Eat Tomatoes or Peppers with Blossom End Rot?

While fruits with blossom end rot may appear to be ruined, it is safe to cut away the affected areas of the fruit and eat the rest. Blossom end rot is not a bacterial issue, and thus does not render your peppers and tomatoes inedible.

It is always good practice to inspect your fruits for any other signs of spoiling. If you see any fuzzy mold or insect damage, it may be best to avoid eating. However, blossom end rot alone does not mean you have to throw away your veggies!

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I hope this helps you take care of your blossom end rot on pepper plants at home. By keeping your soil healthy and following these guidelines, you’ll save yourself a lot of stress. Happy gardening!


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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.

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.