Types of calcium for best bloom formation

strawchicago 5a IL(zone 5a)July 26, 2013

Calcium is needed for best bloom formation, and potassium for bigger blooms. My soil is limestone/dolomitic clay, yet my soil test came back barely adequate in calcium, due to calcium-tie-up at high pH.

In hydroponic experiment with fertilizers, the biggest root growth was through high potassium, some phosphorus, and nitrogen through calcium nitrate. If the soil is sandy, more nitrogen is needed through leaching, and calcium nitrate would supply both calcium and nitrogen.

I checked many sites on gypsum whether or not it lowers soil pH. Some sites says "yes", some sites say "no". So I tested it: I put more gypsum (calcium suifate) on some rose bushes before our week-long rain.

The dark-green ones that like alkaline soil: French Romanticas & Meilland DIDN'T LIKE the excess gypsum: leaves became thinner, and droopy. It's very much like the time I put too much sulfur on Sweet Promise ... leaves became thinner, more droopy.

Roses with musk or multiflora parentage that prefer acidic soil, LIKE gypsum. Excellenz von Schubert, a hybrid musk, does well with added gypsum, so does Annie L. McDowell.

U of CA Extension chart in the below link listed 1 ton of gypsum as equivalent to 5.38 ton of sulfur. It also listed 1.09 ton of Ferric Sulfate as equivalent to 5.85 ton of sulfur. See link below:


If your soil is acidic, hold off the gypsum. That stuff is great in California, where the soil & water is alkaline ... but there are better sources of Calcium for acidic soil, according to the info. from EarthCo. booklet, provided FREE with the $20 soil test (gives soil pH, calcium, magnesium, phosphorus, potassium, and organic matter).

Gypsum provides 22% calcium, 17% sulfur, with salt index of 8.1, used to de-salt sodic soil, also to neutralize bicarbonates in alkaline tap water.

Dolomitic Limestone provides 25% calcium and 10% magnesium, salt index 0.8, sandy soil lacks magnesium

Calcitic limestone provides 36% calcium when the rain water (pH 5.6) breaks it down, low salt index 4.7

Colloidal rock phosphate provides 19% calcium and 18% phosphate. Best for acidic soil, cannot be utilized at pH over 7.

Hard rock phosphate provides 48% calcium and 30% phosphate, cannot be utilized at pH over 7.

Bone meal has 11% phosphorus and 24% calcium. Bone meal cannot be utilized if the pH is over 7.

Superphosphate provides 20% calcium, 12% sulfur, and 20% phosphorus, low salt index 7.8

Wood ashes provides 20% calcium, 2% phosphorus, 7% potassium, magnesium, and all trace elements. CAUTION: Wood ash is very alkaline, pH over 10, will burn roots if applied directly to plants.

Wood ash is great for acidic clay, where my Mom put wood ash on top of a thick layer of leaves. Snow and rain (pH 5.6) counteracts the alkalinity of wood ash. Below is a bouquet picked recently in 90 degrees humid weather. I use both gypsum and sulfate of potash for best blooms:

Here is a link that might be useful: on-line-soil test at EarthCo. for calcium & soil pH & others

This post was edited by Strawberryhill on Mon, Nov 18, 13 at 10:31

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jean001a(Portland OR 7b)

Gypsum helps soil with excess sodium.
The rest is a popular myth.

    Bookmark   August 12, 2013 at 1:32AM
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strawchicago 5a IL(zone 5a)

I found several PDF abstracts on how calcium helps plants tolerate heat. One joint study by Kansas University and Rutgers University quoted "exogenous Calcium enhanced heat tolerance in both tall fescue and Kentucky Bluegrass. "

See link below: http://jxb.oxfordjournals.org/content/52/355/341.full.pdf

From a government website on plant nutrients: Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant. It is also thought to counteract the effect of alkali salts and organic acids within a plant. • Sources of calcium are dolomitic lime, gypsum, and superphosphate." See gov. agricultural link below:

Below is Stephen Big Purple as a 2 months own-root bought as a tiny band from Burlington Roses. It's fertilized with gypsum plus MiracleGro Bloom plus NPK 10-52-10 with all trace elements. See how dark-green the leaves are despite my alkaline clay at pH 7.7. Gypsum greened up the leaves, since it helped with uptake of nitrogen, phosphorus, and trace elements.

Here is a link that might be useful: Calcium as essential plant nutrient

This post was edited by Strawberryhill on Sun, Aug 25, 13 at 12:20

    Bookmark   August 24, 2013 at 3:22PM
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strawchicago 5a IL(zone 5a)

In the book "Right roses, right places", Peter Schneider, a rose grower with over 1,000 roses ... mentioned for his acidic sandy/loamy soil, he spread bone meal on top yearly to supply calcium and phosphorus.

Bone meal cannot be utilized when the pH is above 7, that's why for my alkaline clay, pH 7.7, I use gypsum (calcium sulfate). Also phosphorus mobility is a 1, one study reported that granular phosphorus moved only 1" per year. Phosphorus is best in soluble form. Peter Schneider grows roses in NE Ohio, where there's plenty of rain and snow to make bone meal soluble, and move down his loose soil.

My soil is rock-hard alkaline clay ... it was a disaster when I put bone meal on top. It gunked up, can't move down, and burnt surface roots.

    Bookmark   September 15, 2013 at 1:31PM
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strawchicago 5a IL(zone 5a)

Yesterday Oct 19, I put Jude the Obscure in the ground, bought as a tiny band July 30. So it's 3 1/2 months of growth, resulting in a solid 3-gallon root balls. It was fertilized with soluble gypsum and potassium via bananas. Jude's root-ball was solid, but the top growth was poor, thanks to too much potassium via banana peels. Too much potassium drove down nitrogen.

I get better top growth with a balanced ratio of gypsum and potassium. I bought Gene Boerner from Roses Unlimited end of June. I put equal amount of granular gypsum and sulfate of potash on top. Inside the potting soil I mixed Jobes' Organic for tomatoe NPK 2-7-4 with benenficial microbes. See pic. below of Gene Boerner as 1-month growth, picture taken end of July:

    Bookmark   October 20, 2013 at 12:06PM
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strawchicago 5a IL(zone 5a)

I used triple-super-phosphate NPK 0-45-0 in the planting hole of Queen of Sweden and saw no improvement. Bone meal is better than chemical phosphorus because it's has both calcium & phosphorus, plus many trace elements. As you can see in the below link, chemical analysis of bone meal showed measurement in ppm (1 milligram of something per kilogram soil (mg/kg) )

400 iron, 120 magnesium, 50 manganese, 300 sodium, 200 aluminum, 2,000 sulfates, 20 potassium, 100 zinc, and 400 chlorides.

The biggest portions are 23% calcium and 14% phosphorus ... both essential for root growth. Phosphorus mobility is a 1, compared to 10 for nitrogen. Thus phosphorus via bone meal is best in the planting hole, rather than on top. Studies showed that phosphorus applied on top, only move down 1 inches per year.

Drawback of bone meal? It can only be utilized when the pH is below 7. I already burnt plenty of plants when I tested bone meal in my pH 7.7 soil .... didn't work on top, nor in the planting hole.

Here is a link that might be useful: Ingredients in bone meal

This post was edited by Strawberryhill on Fri, Jul 4, 14 at 10:04

    Bookmark   November 18, 2013 at 10:42AM
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