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All About Blossom End Rot


All About Blossom End Rot

If you’ve ever grown tomatoes, it’s likely that you’ve had the unfortunate experience of watching your fruit rot on the vine—you may have had the most perfect little tomatoes setting all over, only they start turning brown, eventually to an ulcerous black color—and quite literally, the fruits of your labor are wasted. After experiencing such disappointment, frustration, and defeat, who could blame you if you vowed to never garden again?

Maybe you thought your plants were diseased, or perhaps you were a budding gardener with little experience and thought it was normal. Maybe a neighbor told you that you had “bottom rot” which sounds offensive, and you didn’t bother to look into it.

Well, it turns out that your neighbor was sort-of right. “Blossom End Rot,” also known as BER, is a plant disorder that affects Nightshade crops: eggplants, peppers, and especially tomatoes. Not to be confused with a systemic disease such as Blight, which is fatal to your plant, this common disorder is not transmitted through the air or by a vector…BER occurs naturally when the plant is stressed, and can be corrected if caught early.

Before you throw in the towel and declare yourself to have a black thumb, read on to learn more about what you can do to prevent and treat Blossom End Rot.

Blossom End Rot Overview

Identifying BER

When tomato fruits and buds begin to set, they look like tiny pale green peas, with their signature yellow flowers attached at the bottoms. The flower will eventually shrivel, turn brown, and fall off as the fruit (the tomato) develops. This is known as the “blossom end” of the fruit.

To find out if your plant has BER, simply look at the blossom ends of several fruits. In the early stages, young fruit will appear to have what resembles a dark water stain on the blossom end. If it goes unnoticed, eventually that stain will start pitting and turning brown. If you see some fruit ripening too early, take a close look at the blossom end—chances are it’s advanced BER: the bottom half of the tomato is black and concaved, and the fruit is mushy.

Causes of BER

These three main causes of stress in Nightshades are usually to blame for the development of Blossom End Rot:

  1. Insufficient nutrients
  2. Inconsistent or inadequate watering
  3. Rapid growth of the plant

If you’re thinking to yourself “I followed the EarthBox® instructions and I still got BER,” there are a few factors to take into consideration:

  • If this is a new set-up of an EarthBox® system, the dolomite can take longer to break down for the calcium and magnesium to become readily available to the plant.
  • Are you keeping the water reservoir full? Tomatoes are incredibly thirsty plants, and it’s common for just two indeterminate tomatoes in the EarthBox® gardening system to drink 6-10 gallons of water per day. A constant supply of water is best, otherwise be sure to fill the reservoir in the morning and the evening.
  • Because plants constantly have a healthy supply of nutrients and water when growing in the EarthBox®, rapid growth is nearly unavoidable and, with most crops, a good thing for a large harvest.

Prevention & Treatment for BER

There are a few things EarthBox® gardeners can do to help prevent Blossom End Rot on their tomatoes. This means giving your plants some extra attention, but you should be inspecting your crops daily for disease, insect damage, and evidence of other pests anyway.

  • Don’t Start Over Each Season

You can, and should, reuse your growing medium for 8-10 growing seasons, sometimes longer. There is no reason to discard your growing medium each year when you want to replant. Even if your previous crop was diseased, you may still be able to use it if the disease could not withstand a killing frost (confirm any diseases with a soil sample test from your county extension service). If you enjoy starting fresh each year, simply turn your system out onto a tarp or in a wheelbarrow to break up any roots and add in some fresh growing media. If desired, you can take this opportunity to clean out the water reservoir and inspect the system, then set it up according to the instructions.

  • Always Add Dolomite

Dolomite is mined limestone that contains both calcium and magnesium, which are critical elements for the development of healthy tomatoes. This essential ingredient should not be overlooked if you want a successful tomato crop. Each year that you re-use the same growing medium, you are allowing the residual dolomite to break down and become that much more concentrated and available to your tomato plants—which helps reduce the occurrence of BER.

  • Get an Early Start

If you’re itching to get outside to get a head start on your garden, go ahead! Keep in mind your USDA Hardiness Zone may not be frost-free yet (or it might still be too hot in southern regions), so we don’t recommend actually planting your crops. But preparing your EarthBox® systems early will reward you later on when it’s time to get your plants in—not only will you be thanking yourself for saving time down the road, but adding the dolomite from your Replant Kit a couple months early will allow it to start breaking down, making key nutrients more available when you do put your plants in, thus reducing the plants’ risk of developing Blossom End Rot.

  • Use the Right Fertilizer

Using the EarthBox® Replant Kit each season is not just convenient, but it provides the right amount of balanced plant food, in addition to the dolomite and new mulch cover (which helps conserve water for those thirsty plants!). Any plant that yields fruit—tomatoes, peppers, zucchini, eggplant, cucumbers—should be given fertilizer that contains a higher amount of phosphorus (P) and potassium (K). Fertilizer high in nitrogen (N) yields a lot of foliar growth, which is required for growing healthy leaves to help shade growing fruit from the sun, but is better suited for growing herbs and leafy green vegetables. Phosphorus helps boost blossom and fruit development, and potassium helps the overall health and functions of the plant. Likewise, overfertilizing or using a blend that is too strong can be counterproductive and also cause BER.

  • Consider Using a Supplement

Dr. Gary R. Bachman, a Horticulturist and long-time user of the EarthBox® container gardening systems at his Heritage Cottage Urban Nano Farm, discovered years ago that adding calcium nitrate to the EarthBox® water reservoir could significantly reduce the occurrence of Blossom End Rot, as well as improve the health of the plant. Calcium nitrate, or "The Snack" as he calls it, dissolves quickly in water and provides tomato, pepper, eggplant, and squash plants with an extra boost of readily available calcium. To use, add one teaspoon of calcium nitrate down the water fill tube each week. We sell this supplement, which we call the EarthBox Tomato & Veggie Boost.

  • Treat Tomatoes Right Away

In the event your plants still develop BER, don’t fret. There is a quick, inexpensive remedy that usually corrects the disorder within a few days. The earlier you identify Blossom End Rot, the more likely this will help. Carefully remove and discard any affected fruit. At dusk, carefully tip the system towards the overflow drain and let any water out. Mix ¼ cup of Mrs. Wages Pickling Lime with one gallon of water, and add it to the reservoir. The next morning, resume watering as usual and start a weekly treatment of calcium nitrate. It can take several days for this treatment to work, so you might still see some affected fruit. This should decrease over a period of 1-2 weeks. Don’t use this treatment more than one time, as the buildup of too much hydrated lime can cause the roots of your plants to burn.

  • Plant the Right Type of Tomatoes

Some tomatoes, such as paste tomatoes, are more prone to developing BER. Before growing, do a little research and look for varieties, like cherry tomatoes, that are unlikely to develop this disorder.

  • Provide Shade for Your Tomatoes

If you've tried everything and are still having problems, take temperatures into consideration. It's true that tomatoes are warm weather crops and need consistently warm-hot weather to grow big and healthy, but even they have their limits when it comes to direct sun and heat. When tomato plants are stressed from heat or insufficient watering, they tend to pull all their available nutrients–including calcium and magnesium–into their stems and leaves away from the fruit so they can keep growing. Do your plants a favor and move them to a shaded area when it's blazing hot outside, or set up a retractable shade cloth that can be used to give them a little break.

Tell us in the comments: What remedies do you use to grow an abundance of tomatoes?

M ↓   Markdown
K
Kate Pinner
0 points
3 years ago

Someone suggested that pouring a cup of bleach over the potting mix or into the reservoir at the end of the growing season might be beneficial. Any thoughts on this?

T
Terry Browning
0 points
3 years ago

I have a soil recipe I use in my boxes for tomatoes. This includes, equal parts of peat moss, topsoil and potting mix. Also, I mix blood meal and bone meal with iron, gypsum, plant tone and a 8-8-8 fertilizer. Lastly the dolomite with liquid cal. Thanks for the watering tip.

L
Lee Lewis
0 points
3 years ago

Just a warning -- that "cure" for BER using pickling lime almost killed all my earthbox plants last year. The VERY next day they were wilted and sickly. I'm surprised they even bounced back. I followed the directions exactly. Perhaps that recipe is too strong. I was growing Brandy Boy. Finally, it did NOTHING to stop BER, however I did not try to calcium nitrate.

E
EarthBox®
0 points
3 years ago

Hello Lee, thank you for your feedback and we're sorry to hear you almost lost your crop. We would love to learn more about the problem you experienced, so we encourage you to please call or email our Consumer Service Team so we can try to understand a bit more about this issue you experienced. We can be reached Mon.-Fri. 8:30a-4:30p ET at 1-800-4GARDEN if you would like to speak with someone in our office. Thank you!

M
Marylyn Pirtle
0 points
3 years ago

Too late for us this year. Better Boy, Zebra, and sweet peppers all have BER. Only Sun Golds have been harvested. Better luck next year, now that we know.

E
EarthBox®
0 points
3 years ago

Aww...that's too bad, Marylyn. We hope you try again next season and have better success with your tomatoes the second time around!

K
Karen Marks
0 points
3 years ago

Hi! Am loving the earth boxes, but my tomatoes have BER. If I put clean egg shells in the water reservoir, would that help?

E
EarthBox®
0 points
3 years ago

Hi Karen, if you want to use eggshells in an EarthBox, we recommend that you dehydrate them and then grind them into a fine powder. They can then be added to the soil alongside the dolomite. We do not recommend that eggshells be put into the water reservoir as they do not break down quick enough to supplement the soil in any meaningful way. We offer a calcium nitrate packet that can be added to the water reservoir weekly that does help prevent BER. You can purchase that as part of our Tomato Replant Kit - https://earthbox.com/earthbox-accessories/earthbox-tomato-replant-kit

K
Karen Urbani
0 points
3 years ago

Any other ways to treat BER? My two tomatoes have morphed into an octopus of branches covering the patio and I can't possibly dump the earthbox. Also, any alternatives to Pickling Lime? Doubt I can find this during the Pandemic. And should I fertilize with again/regularly since I am growing many more tomatoes than expected?

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Anonymous
0 points
2 years ago

I started adding a liquid concentrate of Calcium/Magnesium (10ml) once a week down the water tube and I only had a few tomatoes with BER from my 6 boxes. I also installed your watering system this past year and had the best harvest I have every had. The constant water paid off.

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Anonymous
0 points
23 months ago

Hi, I’ve planted Armenian cukes for the past two years in my earthboxes, two plants side by side. Numerous flowers appear but never any fruit. They are outside so pollinators have access. We even rent mason and leaf cutter bees every year to help. Any thoughts on how I can get fruit to develop?

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Anonymous
0 points
4 months ago

As a master gardener, I was taught that nightshade crops, particularly tomatoes, need to be rotated and not planted in the same soil year after year. Are you saying that this is not necessary with the Earthbox system, and that the same soil is safe to plant nightshade crops for up to 10 seasons?

E
EarthBox®
0 points
4 months ago

That's correct. You should be reusing the soil season after season unless you have a confirmed plant disease like blight.

B
Barbara Petzen
0 points
3 years ago

I've heard that dropping a Tums into the watering tube occasionally can also help prevent BER. Would love to know what your advice is on this, and if others have had success with this cheap and easy method?

G
gary bachman
0 points
3 years ago

Barbara, you would need to add something like 275 Tums to equal just setting up using the correct amount of dolomite

K
Kathy Sieling
0 points
3 years ago

On my better boy tomatoes, looks like one or two small tomatoes are developing blossom end rot, the others are not. Planning n adding calcium to the boxes today, but should I pluck off the small ones that appear to be developing blossom end rot?

E
EarthBox®
0 points
3 years ago

Hi Kathy, Any tomatoes that have Blossom End Rot (BER) should be picked and discarded as soon as possible. Picking off the affected tomatoes as soon as possible will allow the plant to put energy into producing more flowers and fruit. Be sure to add 1 teaspoon of Calcium Nitrate to the water reservoir one time each week to help prevent BER.

K
Kathy Sieling
0 points
3 years ago

Where do purchase calcium nitrate and all I could find is Bonide Rot Stop.

E
EarthBox®
0 points
3 years ago

Your local garden center should have some, or you can also buy it from us by calling 800-442-7336.

S
Sharon Babbitt
0 points
3 years ago

I have used the earth box planting mixture.. Bought the refertilizer packs... I followed instructions to a tee.. but my zucchini have big leaves and my zucchini get about 2-3 inches long and rot off... not sure what is happening. Can you tell me what is wrong?

E
EarthBox®
0 points
3 years ago

Hello Sharon, thank you for your question. The problem you are describing with your zucchini plant is lack of fertilization. Basically, your female squash flowers (the ones with the tiny zucchini fruits behind the blossom) are not being pollinated. The fruit will only grow so much and then it begins to rot if the flower did not receive pollen from the male flowers (the flowers without the fruit and with just a straight stem behind the blossom). You can pick the male flowers and manually pollinate the females if you do not have any bees, butterflies, or other pollinators in your area, which will allow the tiny fruits to "set" and mature into full-size.

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Anonymous
0 points
19 months ago

Don't you mean "lack of pollination" rather than "lack of fertilization"?

L
Laura Fulton
0 points
3 years ago

How do I apply rot stop (Calcium 9.2% solution to earth box container to prevent blossom end rot. My plants are small now. Two in one earth box. Thank you

E
EarthBox®
0 points
3 years ago

Hi Laura, Bonide Rot Stop is a foliar spray. Directions on their label state to "apply to the point of run-off onto the foliage and fruit during periods of rapid growth or following excessive rain fall." We advise you apply this in the evenings when temperatures are lower to avoid foliage burn. They do not recommend using this regularly, as it can cause leaves to burn if used more often than every 7 days.

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Anonymous
0 points
8 months ago

I had a bad time with BER a few years back and started adding calcium nitrate once a week. Since then I’ve started adding it before it starts and so far so good. I was reading and noticed that I should reuse the soil every year, I haven’t been doing this but I’m really glad I don’t have to empty the boxes and buy new soil every year 😮. This year I got mixed up and have been adding it to tomatoes and squash, not peppers. Now I have quite a few peppers to remove.. 😐. I’m at the age where I have to learn things over lol Julien Bowles

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