If you find black spots at the bottom of your tomatoes, you have blossom end rot, and you need to fix the issue!
You waited for your tomato harvest for months; finally, unripe fruits cover your plants. As they ripen, you notice rotten, sunken, black spots on the end of the fruits. Blossom end rot arrived in your garden, an unwelcome visitor, and now, you have to learn how to fix blossom end rot before your entire harvest is ruined.
It’s not difficult to spot blossom end rot. These are yellow or brown water-soaked stains at the bottom of the fruits, where the blossoms used to be. As the tomatoes ripen, this spot turns into a hard or decaying brown or black patch.
Despite what others tell you, blossom end rot is a disgusting disease that infected your plant, nor does it indicate that insects took over your plant.
Blossom end rot affects tomato plants, but it also affects pepper plants, eggplants, summer squash, winter squash, melons, and cucumbers. Members of the nightshade family and gourd family are susceptible to blossom end rot.
Just because it appears in your garden doesn’t mean that all hope is lost! You can fix blossom end rot if you understand why it happens and the steps to stop it on its track.
What is Blossom End Rot?
Blossom end rot is a physiological disorder that causes the disfigurement of the fruit. This isn’t a disease that may spread from plant to plant like a contagious pathogen. It’s also not a soil-borne fungal infection living in the soil, since BER is not caused by bacteria or fungi.
Despite being frustrating, this is a common problem, so you are far from alone!
Home gardeners most often discover blossom end rot during the early part of the growing season. However, it may appear at any time, depending on environmental conditions, such as excessive rain or heat waves.
You may notice a single cracker at the bottom of the fruit that starts small and grows larger over time. Sometimes, BER starts off with two or three lesions, but they are always on the blossom end of the fruit, never on the top.
What Causes Blossom End Rot?
You know what blossom end rot is not; it’s not caused by bacteria, fungi, viruses, pests, or diseases. Despite what you may have read, it’s also not due to not enough calcium; chances are your soil has sufficient calcium available, especially if you added any crushed egg shells before planting or in your compost.
Instead, blossom end rot is a result of inadequate intake of calcium. The plant’s roots should absorb calcium from the soil, spreading it through the stems, leaves, and fruits.
This is why adding more calcium or using calcium supplements to your soil will not solve blossom end rot. Most garden soil contains calcium. If you want to be sure, take a soil test before amending to discover what nutrients your garden needs the most.
What is most important to remember is that amending soil with more calcium sources will not fix blossom end rot, nor will it reduce the possibility of BER happening.
The issue with BER is the lack of movement of the calcium from the soil to your plant. Plants require calcium for cell growth, and plants need ample amounts for developing fruits. This is similar to how humans need calcium for bone growth and development.
The problem is that new leaves compete with newly forming fruit, and they both need calcium. Then, you add stress factors like too much nitrogen, drought, excess moisture, and high heat. All of these factors lead to the reduction (or complete stopping) of calcium reaching the fruits growing on your plants.
What really is the problem that causes blossom end rot?
I’ll get to that in a moment, but I want to make a few things clear.
No matter what websites tell you, it’s impossible to treat blossom end rot by using fungicides, Epsom salt, powdered milk, or homemade sprays for plants. These sound like they might work, but unless they solve the problem with the calcium intake, they will not fix blossom end rot.
In many cases, the issue will fix itself over time, but you can take steps to prevent blossom end rot or reduce the length of time it bothers your plants.
Water is Causing Your Calcium Issue
Calcium comes to your plant through a process called mass flow rather than diffusion, which is how other nutrients arrive to your plant’s roots.
Mass flow is when water carries a dissolved nutrient into the roots, meaning that calcium arrives to your plant via water absorbed by the roots.
So, if there isn’t enough water arriving into your plant, it prevents the plant from getting all of its calcium needs as well. So, your plants will show signs of calcium deficiency, but garden soil typically has plenty of calcium.
Your garden soil can be full of calcium, but if your plant’s roots cannot access it, then you end up with a lack of calcium. It’s also the truth for tomato plants grow in pots, especially if you fill your containers with commercial potting soil and add a balanced fertilizer.
So, the trick is truly making sure your plants can access the calcium already present in the soil. If you exhaust that and nothing changes, then you may actually have a calcium deficiency in your garden soil.
How to Fix Blossom End Rot
In most cases, blossom-end rot is preventable, and consistent soil moisture is the best way to fix blossom end rot. However, sometimes, Mother Nature may mess with your watering schedule. A period of dry weather and failure to change your watering schedule could lead to blossom-end rot for your tomato plants.
1. Remove All Affected Tomatoes
The first thing you have to do is remove all of the affected tomatoes. Your tomatoes cannot be saved, and there is no way to make those fruits better. You can save the plant, and that is your focus.
It is safe to put affected fruit with blossom end rot into your compost. These fruits aren’t infected with a disease or pests, so they won’t damage your compost pile.
2. Reduce Nitrogen Application
The next step is to make sure you don’t add more nitrogen to your garden soil. Nitrogen is a vital nutrient your plants require for proper growth, but excess nitrogen is detrimental. Excessive nitrogen, especially when combined with excessive temperatures, leads to your plants growing rapidly before the other compounds have time to catch up and give more calcium to the fruits.
Fertilizing tomato plants properly is essential. I’ll discuss this a bit further below, but a balanced, all-purpose vegetable fertilizer will provide your plants with the nutrients needed without being excessive.
3. Water Your Plants Consistently
One of the most important things to do to fix blossom end rot is to water your tomato plants consistently. Skimping on watering in the early growing season is one of the leading causes of blossom end rot.
Blossom end rot is most consistently linked to moisture in the soil, so inconsistent watering is most often the true root of the issue.
Calcium moves through the plant with ample moisture, so underwatering or suffering through periods of drought leads to a calcium deficiency in your plants. The plants are unable to circulate the nutrients throughout the entire plant.
Tomato plants need to be watered deeply, but you also want to avoid waterlogging the soil. These plants have long roots that benefit from consistent watering. If you provide your plants with one to two inches of water per week, that is often sufficient, unless you are facing high temperatures or a heat wave.
However, tomatoes grown in containers need to be watered more than plants in the ground. The water leeches out faster.
4. Apply Mulch to Reduce Water Loss
We all have busy lives, so watering every day may not be an option for your family. Our water pressure makes a drip irrigation system out of the question for not. That’s where an organic mulch comes in clutch.
Applying mulch around your tomato plants (and other plants) holds the moisture into the soil. So, surround your plants with two to four inches of organic mulch, such as:
- Grass Clippings
- Wood Chips
- Pine Needles (this could add more acid to your soil ph)
Organic mulch offers other benefits for your garden besides retaining moisture. It also prevents weeds, keeps soil temperatures regulated, and adds more nutrients to the soil over time. Mulch also prevents water from splashing onto the leaves, and that decreases fungal diseases.
5. Keep Your Garden Soil pH at 6.5
The right soil pH helps with calcium uptake into your plant. 6.5 is an ideal pH level because it allows other essential nutrients to become more readily available for your plants to use.
6. Avoid Disturbing the Plants’ Roots
Another thing you can do to prevent blossom end rots is to avoid disturbing the plant’s roots. Deep cultivation of the soil near the plants after the fruit sets is a problem.
If you need to get rid of weeds, do so by pulling them by hand or using a hoe to scrape the weeds away lightly. Mulch helps to suppress unwanted weeds and seedlings from growing.
Disturbing the soil, especially when the weather is hot and dry. It affects the plant and its ability to draw up moisture.
7. Use Fertilizer Appropriately
If you have tried other tips to fix blossom end rot, you will want to make sure you completed a soil test. Head to your local extension office; they offer comprehensive soil tests that will look at if you have a lack of calcium and other nutrient deficiencies in your soil.
At this point, it is safe to use a calcium supplement if you know your soil lacks this nutrient. There are several ways to add calcium to soil; you can read my full guide below, detailing all of the ways to improve low calcium levels.
A few suggestions include:
- Apply lime to the soil, such as this Garden Lime by Jobe’s Organics.
- Add eggshells to your soil when planting, and make sure to put eggshells regularly into your compost bin.
- Try a foliar spray to give the leaves and plants a direct boost of calcium, such as Bonide Rot-Stop.
- Add calcium carbonate, such as oyster shells, to your garden beds.
Related: 9 Simple Ways to Add Calcium to Soil
Can You Eat a Tomato with Blossom End Rot?
If you have dozens of ripe tomatoes with blossom end rot, you may wonder if it’s safe to eat those tomatoes still.
The answer is yes, you can simply cut away the rotted parts of the tomato and use the rest. However, you may find that the tomato fruits have an unappealing texture and less flavor than you anticipated.
These tomatoes aren’t good for food preservation; you generally won’t want to can with these fruits.
Does Epsom Salt Stop Blossom End Rot?
No, adding Epsom salt to your soil will not fix blossom end rot. However, it can lead to a worsening of the problem.
Remember, BER happens due to inconsistent watering and a lack of calcium; Epsom salt is not a source of calcium. Instead, it contains magnesium sulfate, and magnesium battles against calcium ions in the plant’s root system.