Forgot to add Dolomite/Lime to my mix

bdobs(8b or 9 SF Bay Area)April 23, 2008

I forgot to add any Dolomite to my potting mix in my EarthTainer when I planted my Tom's,

Should I be worried about blossom end rot?

Would it help to add some to the top and around the plants?


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rnewste(8b NorCal)


I would definitely add in at least a cup of Dolomite Lime ASAP, before your plants begin extending their root system into the potting mix. You can carefully trowel it in outside the immediate plant area down about 3", and it will disperse over time throughout the container.

This is what I bought at SummerWinds:


    Bookmark   April 23, 2008 at 9:10PM
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bdobs(8b or 9 SF Bay Area)

Thanks Raybo
I have the same stuff fom Navalets.
I put in in my other box, I just brain farted on this one

    Bookmark   April 23, 2008 at 9:25PM
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gardenscout(z6 NE RI)

You are probably still going to get BER in the beginning of the season. It's just the way it is.

The lime will mostly just make the ph more tomato friendly, but doesn't cure BER.

    Bookmark   April 24, 2008 at 12:13AM
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sprtsguy76(Santa Clara Ca. 9b)

I'm must be missing something here. Why would you want to add lime? Wouldn't that raise your ph in your boxes. Tomatoes do best in a media with a ph of 6-7. The potting mix I put in my earhtboxes has a ph of 7.5 at best. Is the calcium that important?

    Bookmark   April 24, 2008 at 1:08AM
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jbann23(6 RI)

Calcium, in the form of dolomitic lime is indeed important since it will help get the Ph to the desired range. BER is caused by many stresses to the tomato plant. Overwatering can cause it, disturbing the roots also. Tomatoes do use calcium but adding it doesn't seem to stop BER. Apparently the calcium has to move through the plant easily and stressing the plant interupts that function. So, don't swear too loudly when the first fruits come down with it, might be stressful.

    Bookmark   April 24, 2008 at 7:53AM
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rnewste(8b NorCal)


I had the same "mental problem" of adding Lime. When I measured the pH of the stock potting mix, I got a reading of 6.5, which is supposed to be the "sweet spot" for tomato growth. After adding in Lime, the pH read 6.9. So as jbann says, there must be something else going on here vs. just the pH reading as to the rationale of adding in Lime. The EarthBox folks are adamant in their video that adding in Lime is essential. May be one of those Mysteries of Life....


    Bookmark   April 24, 2008 at 11:15AM
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shelbyguy(z5 IL)

The more peat you use, the more lime you will need. Period, paragraph.

    Bookmark   April 24, 2008 at 1:00PM
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andrea_san_diego(z10 So Cal)

Newbie here seeking your wisdom. Does the addition of dolomite only apply to those using the Earth Tainer? Mine are in potting mix in big containers and raised beds. Also I've been advised to put 2 regular aspirin into the planting hole. Does the aspirin serve the same purpose as the dolomite?



    Bookmark   April 24, 2008 at 1:59PM
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rnewste(8b NorCal)


The "EarthTainer" is simply a generic name I came up with to avoid any conflict with the good folks at the EarthBox Company, who are trying to protect their registered trademark. My design is a modification from "joshos" home made design, and there is nothing different from it pertaining to what to put in the potting mix.

Generally, for any container growing (especially tomatoes) it is recommended that you add Lime. I have read of others who add Epsom Salts instead, or in combination. Never heard of the aspirin additive, but others may help you out here from their own experiences.

I am doing an "A/B" comparison this year in a few of my EarthTainers with Lime on one side, and Epsom Salts added to the other side. Two identical plants, so I will post my personal experience later this year on which worked best.


    Bookmark   April 24, 2008 at 2:57PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Generally, for any container growing (especially tomatoes) it is recommended that you add Lime.

I'm sorry mewste but I have to disagree with this. While I know that Earthbox now recommends adding it (they didn't use to) and while the results of your comparison study will be interesting, I don't think we can claim that "adding lime is generally recommended".

Adding lime to container mix is strictly optional. As far as BER is concerned, it is another of those old wives-tale fixes like eggshells, Tums, etc.

Many folks, myself included, successfully grow many things, including tomatoes, in containers without ever adding any lime to the mix. ;)


    Bookmark   April 24, 2008 at 4:21PM
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rnewste(8b NorCal)

Hi Dave,

I DO hope you are right - as I spent $21 buying boxes of Dolomite Lime this year, and I would love to eliminate that expense again next year. Why then are the EarthBox people so insistent on supplying a first year starter kit of Lime in with every EarthBox? If they found it wasn't necessary, they could eliminate a cost of goods sold expense.

Do you make your own mix that may be different from commercial mixes like Miracle Grow or StaGreen? Perhaps for the average gardener who does not have access to blending their own mix as you may have, the instruction to add in Lime may be an insurance policy of sorts. Anyway, I'll be able to tell if adding in Lime or Epsom Salts results in better productivity in my EarthTainers later this year. ...the mystery continues.....


    Bookmark   April 24, 2008 at 4:48PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Earthbox FAQ: "What is Dolomite? Is it used only for tomato plants?

Dolomite, or hydrated lime, can be used for any plant, although it is critical for healthy tomatoes. Tomato plants need a lot of calcium in order to produce healthy fruit; dolomite satisfies this requirement."

Nice, general, non-specific, cover-your-backside statement with no explanation offered. But "lime being critical for healthy tomatoes" is not conventional wisdom - depending on soil pH it can even be hazardous. And their statement reflects the old school of thought that lack of calcium in the soil causes BER. I would also guess that it is a way to raise their prices (which they have). ;)

No, I don't mix my own container mix. I use Pro-Mix BX or Metro Mix 360 to which I add low-dose, timed-release fertilizer and then feed periodically through the season. EB doesn't want you adding additional fertilizers of any kind at any time (per their FAQ) and that too is not conventional wisdom. But I can't see how just lime would compensate for a regular feeding of a balanced supplement.

Hey! if it works for EB which is an artificial enviroment anyway for growing, fine, but let's not assume it is the generally accepted way to go for all situations be they in-ground or containers. ;)


Here is a link that might be useful: Earthbox FAQ

    Bookmark   April 24, 2008 at 5:22PM
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sprtsguy76(Santa Clara Ca. 9b)

Keep us informed on your experiment. I will be watching closley.

I use and organic granular fertilizer (Dr. Earth) and noticed it has some soft rock phospate in it which is one of the best natural sorces of calcium and phosphorus. So I'm not rerally worried about calcium. I wonder if all fertilizers contain some amount of calcium? Does anybody know?

    Bookmark   April 24, 2008 at 6:31PM
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rnewste(8b NorCal)


I am evaluating productivity of 2 organic granular fertilizers (Fox Farms Peace of Mind, and TomatoTone:

Toy your question re: Calcium content, the Fox Farms contains about 5% Calcium:

While the TomatoTone contains 3%:


    Bookmark   April 24, 2008 at 7:19PM
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timmy1(6a ri)

The pH of your potting mix in your earth-tainer is determined more from the pH of your source water. If your source water pH is high, your media pH will slowly climb. Likewise if your water pH is low, the media pH will drop accordingly. The media will generally contain dolomitic limestone to adjust your beginning pH to about 6.5

If you are growing in an inert soilless peat based media like MG potting soil or Pro-Mix etc., you are absolutely growing hydroponic by definition.

With all the required nutrients, balanced pH and proper watering schedule you will have ZERO BER!

    Bookmark   April 24, 2008 at 8:16PM
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trungson(9b San Jose CA)


This is from last year so do you have the A/B testing results now? I'd love if there is any conclusion to be considered.

    Bookmark   May 8, 2009 at 7:25PM
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Last year i did not use dolomite and I had a lot of BER.

Also, last year I used a soil with slow release fertilizer and opted to not add 2-3 cups of fertilizer at the top. All my plants were weak and low producers!

This year I have followed the instructions and so far all plants are bigger then the ones planted in my raised beds.

    Bookmark   March 27, 2011 at 5:46PM
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