Blossom End Rot In Tomatoes – Why Is My Tomato Rotten On Bottom
It’s disappointing to see a tomato in mid-growth with a bruised looking splotch on the blossom part of the fruit. Blossom end rot in tomatoes (BER) is a common problem for gardeners. Its cause lies in a plant’s inability to absorb enough calcium to reach the fruit.
Read on if you’re seeing tomatoes rotting on the bottom and learn how to stop tomato blossom end rot.
Tomato Plants with Blossom Rot
The spot on the fruit where the blossom once was marks the center of blossom end rot. Typically, the problem starts on the first flush of fruits and those that haven’t quite reached their full size. The spot appears watery and yellowish brown at first and will grow until it destroys much of the fruit. Other vegetables like bell peppers, eggplant, and squash can be subject to blossom rot as well.
What blossom end rot is telling you is that the fruit is not receiving enough calcium, even though there may be ample calcium in the soil and the plant’s leaves.
What Causes Blossom End Rot in Tomatoes?
It’s all about the roots and their ability to carry calcium upward. There are several things that will prevent a tomato plant’s roots from uploading calcium to the plant’s fruit. Calcium is transported up from the roots to the fruit by water, so if you’ve had a dry spell or haven’t sufficiently or consistently watered your plants, you may see blossom rot.
If you’ve given your new plants too much fertilizer, they may be growing too quickly, which can prevent the roots from delivering enough calcium fast enough to keep up with the growth. If your plant’s roots are crowded or waterlogged, they may not be able to draw calcium up to the fruit.
Finally, although not as common, your soil may be lacking in calcium. You should do a soil test first and, if this is the problem, adding a bit of lime should help.
How to Stop Tomato Blossom Rot
Try to wait until your soil warms up to 70 degrees F. (21 C.) before planting new tomatoes.
Don’t fluctuate with watering. As your tomatoes grow, make sure they’re getting a full inch (2.5 cm.) of water each week, whether it’s from irrigation or rainfall. If you water too much, your roots may rot and give you the same negative results. Likewise, if the tomato roots get dry or crowded by others, they won’t do their job of carrying up sufficient calcium.
Consistent watering is key. Remember to never ever water from above, but always water tomatoes at ground level. You may want to place some organic mulch around the plants to retain moisture.
Tomato end blossom rot will usually affect the first round or two of fruits. Although blossom end rot can leave the plant vulnerable to disease, it is not a contagious condition and won’t travel among the fruits, so unless you find you have a severe calcium deficiency, there’s no need for sprays or fungicides. Removing the affected fruit and continuing with a consistent watering schedule may clear the problem for the fruits that follow.
If you do find your soil is truly lacking in calcium, you can add a bit of lime or gypsum to the soil or use a foliar spray to help the leaves take up calcium. If you have an otherwise lovely tomato that’s rotten on the bottom, cut the rotted part away and eat the rest.
Looking for additional tips on growing perfect tomatoes? Download our FREE Tomato Growing Guide and learn how to grow delicious tomatoes.
How to Prevent Blossom End Rot
Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
You’ve been carefully nurturing your tomato plants all summer and finally they are setting fruit. But, wait. What’s that soft black spot on the bottoms of your tomatoes? You’ve got blossom end rot.
Does Epsom Salt Help Blossom End Rot?
Although commonly recommended as a “cure-all” for tomato plant, Epsom salt is not a good choice for stopping blossom end rot. It might even make the problem worse.
Epsom salt is magnesium sulfate. It contains no calcium. Magnesium and calcium ions vie for the same spots in the soil and plants, so extra magnesium may make exacerbate a calcium deficiency. It's better to use the options above to make calcium more available.
Note – a little extra magnesium at blossom time can help with fruit set. Just don't go overboard.
How Can I Fix Blossom End Rot??
There is nothing more irritating or disheartening than to see that your lovely ripe veggies/fruits are rotting from the bottom.
It is a pain to see so many days of hard work, patience and persistence go in vain.
While there is nothing that you can do with those that have already been inflicted with blossom end rot, you can prevent it from spreading in other fruits/veggies as well.
Try some of these preventive measures to get started:
1. Check the pH Level of Your Soil
It’s best to check the pH level of your soil before planting. There are gadgets present which can instantly check the level of your soil.
You should try the following simple DIY method (shown below) that you can do using simple household items that can be found in any home.
Remember, the perfect soil pH level is 6.5.
DIY Vinegar and Baking Soda Test:
This DIY soil pH test is very simple and gives you the result right away and in a visual manner so it’s easy to identify the pH of the soil. Get a cup full of the soil from different places in your garden.
Get 2 separate containers and put 2 spoonfuls of the soil in each container. Add ½ cup vinegar in one container. If the soil starts to fizz then you have an alkaline soil with pH between 7 and 8.
If it doesn’t fizz then take the second cup and add some distilled water until the soil in the cup becomes muddy.
After that add ½ cup of baking soda. If it fizzes then your soil is acidic with pH between 5 to 6. If both containers have no reaction then that means that your soil is neutral, which is good news.
Some tips for Adjusting pH Levels
Now that you have found the pH level of your soil, you can adjust the calcium according to the test by putting some crushed eggshells in the soil.
You should use eggshells, as they have high calcium content. Also, add lime to raise the pH levels of your soil.
You should till some lime into the soil at a depth of about 6 to 8 inches in order to provide an effective change.
Other recommended materials include gypsum and bone meal. Do it only if the tests are positive and it would be best to consult an expert before taking any action.
Another recommended product to correct calcium deficiency for tomatoes is Southern STOP Blossom-End Rot of Tomatoes.
2. Avoid Using Too Many Fertilizers
As I stated above that too much nitrogen is also responsible for blossom end rot, so don’t use too much fertilizer on your soil, especially those that have high amounts of nitrogen in them.
That’s not to say that you should cut out the use of fertilizers completely, just use them less often and try to use ones where nitrogen content is less but phosphorus content is high.
At this point, the best treatment for your plants is some good old compost or mulch.
You may also check out Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer Poly Bag which helps for m ore abundant crops and more nutritious and tasty vegetables.
If you want to know more about ideas on how to create homemade fertilizers, check out 5 Of The World’s Best Homemade Vegetable Garden Fertilizers.
3. Use Mulch
It would be best if you surround the soil around your plant with some mulch to conserve the moisture in the soil. It also provides your plant with some nutrients.
4. Keep Track Of Your Watering Routine
The dry season needs more water. Make sure that the soil is moist to a depth of 6 inches.
Check out this durable and expandable garden hose. This flexible and hard wearing hose is perfect for watering plants in your garden.
5. Good Drainage
When watering, remember to provide the plant with some good drainage as too much water can have the opposite effect.
It means that the roots will not be able to get the proper calcium intake with all the water in the soil.
An awesome alternative that can be used indoors for under potted plants is this GOLDEN MOON Artificial Grass Turf Tile Interlocking Self-draining Mat. Highly recommended!
6. Don’t Let your Soil Dry Out
In times of drought, it is best to set up a uniform supply of water using an irrigation system.
This system used in conjunction with mulch traps the moisture and ensures that the roots of the plants don’t die out.
Do not water the leaves since it increases the possibility of disorder on fruits and vegetables.
A down-to-earth, complete manual for achieving great gardening results with your own rich, organic soil can be found here: Building Soil: A Down-to-Earth Approach by Elizabeth Murphy.
If you are a beginner and you need tips and ideas on vegetable gardening, check out 27 Tips for Beginner Vegetable Gardeners.
7. Fortify your Crops at Planting
Fortifying your crop at planting is another way of ensuring that your crop remains healthy and does not suffer from blossom end rot.
You can do this in various ways such as using garden lime or adding 2-3 calcium antacid and even Tums tablet to the planting hole.
This will give your plant a calcium boost right from the beginning.
Make every month a gardening month with The Year-Round Vegetable Gardener: by Niki Jabbour's proven techniques for year-round growing and harvesting.
8. Commercial Products
You can find products to help you fight blossom end rot in gardening stores. Follow the directions on the label, but these products are not a permanent fix.
It will only save the remaining crops that have not been infected. This is when you use the methods mentioned above.
A cheap and recommended product to use is Calcium Nitrate 15.5-0-0 Fertilizer.
9. Home-made Solution
If you see signs of blossom end rot appearing on your crops, you can try to hold it at bay with this home-made solution.
Just add 2-3 calcium carbonate antacid tablets to about a quart of pure water and 8 ounces of milk.
Mix it well and then irrigate your plants regularly with this solution. It will help prevent other fruits and veggies from damage.
While this is not a foolproof solution, but it may stop blossom end rot from spreading further and ruining other crops too.
Organic Pest Control by John Parker is an exceptional book full of suggestions, recipes and project instructions for doing away with the pests that attack your garden.
10. Test your Soil
Get your soil tested each spring before planting. This is a great way to avoid the trouble of having a blossom end rot.
Check out this innovative and inexpensive soil test kit here: Luster Leaf Rapitest Soil Test Kit.
How To Keep Tomato Plants Healthy From Blossom Rot & Blight
There is one major practice that helps eliminate both tomato blight and blossom end rot, and that is crop rotation.
The Importance of Crop Rotation
Tomatoes are one of the most susceptible vegetable plants when it comes to soil-borne disease. In addition, they are also heavy feeders of the nutrients that are in the soil. One of which is calcium, which when depleted, is the cause of blossom end rot.
By planting over and over again in same location, the soil begins to lose valuable nutrients such as calcium. And at the same time, it is also more likely to become infected with the spores that cause blight.
But by rotating plants each year, you instantly minimize the potential for both issues. A new space in the soil means less chance blight spores are present. And more importantly, less chance the soil has been depleted of calcium from previous years crops.
Moving vegetable crops around to a new location in the garden is one of the best ways to fend of disease and pest issues.
For best results, never grow tomatoes in the same space for a minimum of 3 years. For potted tomatoes, the soil should be changed out every year. This gives your plants the best chance of success right from the start!
With that in mind, here is a look at additional ways to help keep your tomato plants healthy, and eliminate both blossom end rot and blight:
Preventing Blossom End Rot
Of the two issues, blossom end rot is a bit easier to manage. As mentioned above, it is not caused by disease, but a deficiency of calcium in the soil.
In addition to crop rotation, adding a bit of calcium and additional nutrients at planting time is usually enough to solve the issue.
Blossom end rot is caused by a lack of calcium in the soil.
When planting, always mix in a shovel or two of compost in the planting hole of each plant. Compost is by nature loaded with a host of nutrients that help plants grow strong.
But to really boost the calcium, add in 3 to 4 crushed eggs shells in the planting hole as well. See : Planting Egg Shells With Tomatoes As the shells break down in the soil, they help to release calcium to the tomato plants roots.
Finally, mixing in a 1/4 to a 1/2 cup of worm castings in the hole will really build in the nutrients that tomatoes need to thrive! Product Link : Worm Castings
Eliminating blight is a bit more tricky, and really involves a few more steps to keep your tomato plants safe and healthy. Beyond rotation, which again is THE biggest key, there are a few additional methods that help to keep your plants safe.
Keep tomato plants healthy by mulching and trimming up leaves to help eliminate spores from splashing up onto plants.
As plants grow, keep the bottom of each plant trimmed up to at least 6″ above the soil line.
This allows light and circulation into the plant, and makes it harder for spores to splash up to infect leaves. Good air circulation is also a big key in preventing mold on plants as well, and will go a long way to keeping your tomato plants healthy.
Always prune back any foliage that shows signs of blight or disease right away. Be sure to keep any of these infected or diseased branches out of the compost pile.
Every time it rains or the garden is watered, spores can splash up and find a home on leaves. But by mulching, you reduce or even eliminate that problem entirely. A few inches of straw, shredded leaves or grass clipping around plants goes a long way in solving the issue.
Crop rotation and mulch both are big keys to keep plants healthy from blight and blossom rot.
As a final tip, be sure to clear out your tomato plants (and all vegetable plants) at the end of each growing season. Allowing old plants to over-winter is inviting disease and insect problems to take hold in the garden soil.
Pull up your plants, roots and all, as soon as they are done producing. We do not compost our tomato plants.
There is simply too much chance to pass on disease. We actually burn ours in the fire pit to kill off any spores, bacteria or insects, and then add the ashes to the pile.
Here is to keeping your tomato plants healthy this year! Happy Gardening – Jim and Mary.