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

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

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.

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:

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

Nutrients lock-up can be from many factors:

1. Too much magnesium like my heavy clay, very alkaline soil which shoots up the pH and makes concrete out of my clay.

1. Tap water high in salt, plus UNSTABLE calcium hydroxide (used to sanitize tap), which makes concrete out of clay. Calcium hydroxide binds with potassium, phosphorus, and magnesium into insoluble compounds.

1. Gypsum with calcium sulfate is used to de-salt saline soil. But gypsum has one drawback: 17% sulfur, which will push soil pH down, plus roses which like it alkaline HATE that stuff.

1. If the pH is too low, such as acidic soil plus tons of acidic rain, there's nutrients lock-up due to excess aluminum (toxic to roots, excess at low pH), plus calcium & potassium are less available at low pH.

Thus testing your soil pH with red-cabbage juice is the 1st step. My soil is greenish-dark-blue (pH over 8), with amended soil it's medium-blue (pH 7.7).

http://forums.gardenweb.com/discussions/2132487/cheapest-way-to-test-soil-ph-using-red-cabbage?n=26

http://forums.gardenweb.com/discussions/2134007/red-cabbage-ph-test-of-blood-meal-corn-meal-compost-etc?n=25

Straw: Maintaining correct soil pH is turning out to be one of the fundamental aspects in rose growing. Everything goes wrong if the soil pH is not appropriate. Red cabbage is not available to me locally. What kind of pH meters work the best?

Khalid: good question, I once spent 4 hours researching on the best pH meter to buy. Then I found even the $200 needs re-calibration in known-solutions for it to be accurate. Even that is not correct on coffee ground. When folks stick a pH meter in coffee ground for 5 min, they declare it's acidic. But if they let it soak long enough, it will be neutral. Coffee grounds is a buffer, it neutralizes a medium, given time.

Litmus test, based on a solution is much more accurate, since it allows pro-longed soaking to allow water, be it acidic rain, or alkaline tap water to interact with soil elements.

Litmus paper to test a solution can be bought from fish-tank place for $5. Soak a tiny sample of soil with acidic rain water, let it soak for 20 min, then test with a litmus paper. If soil sample is soaked in alkaline tap water, the solution will be more alkaline.

Too bad that red beet can only be used between pH 10-13, versus red cabbage used from pH 1 to 12. . Below link shows how to use red-beet vs. red-cabbage juice, using a blender and strainer to strain the juice:

https://www.erowid.org/archive/rhodium/chemistry/equipment/ph-indicator.html

*** From Straw: I used to red-cabbage test up to 10 samples at a time, but I don't pH-test much anymore, unless it's a new additive. Roses are different from each other. Some rose' roots secret lots of acid (Dr. Huey-rootstock, and Centifolia) .. that will make leaves dark-green & thinner and prone to fungal attacks.

Some own-root roses are so wimpy that they don't secret acid, and leaves are pales (esp. those with multiflora parentage) .. these need sulfur (as in gypsum, sulfate of potash, or decayed organic matter). Even when the pH is perfect like potting soil at 6.5, prolonged rain can leach out minerals, and calcium & potassium & trace elements need to be supplied regardless of pH level.

Looking at roses' leaves and understand nutritional deficiencies is far-better. pH of a soil changes constantly: with acidic rain (pH 5.6), it becomes more acidic. With alkaline tap water like my at pH 9, soil becomes alkaline instantly .. just one-tap-watering is enough to cause pale leaves in my roses.

In my garden, rain leaches out nitrogen, potassium, and calcium & trace elements like iron & copper .. so roses' leaves become thinner and paler after acidic rain.

Nice work done by graduate student Alex Barron. The below article shows how limestone, iron, and copper is corroded by rain.

http://www.madsci.org/posts/archives/2001-01/978816088.Es.r.html

" Acid deposition can corrode bronze (which is mostly copper), iron, steel (which is mostly iron), and copper much more quickly than under natural conditions ... Some researchers in Britain did exactly that, in what was called the National Materials Exposure Program. They placed many different types of metals and rocks (which are also vulnerable to damage) outdoors .... they found that “mild steel” was corroded the most, followed by galvanized steel, copper and then aluminum, which was hardly affected. Some rocks, like limestone (which dissolves in acid), are damaged more quickly – huge amounts of damage to sculptures and buildings have occurred throughout areas affected by acid rain." Alex Barron.

I bring up this thread since the pic. of Gene Boerner in a pot (scroll up and you'll see) is the best growth I had ever done for 1-month-own-root, thanks to slightly acidic potting soil to release the trace minerals in bone meal.

I used Jobe's Organic NPK 2-7-4 (with bone meal & chicken manure), plus a special bacteria to break down potting soil into humus. I also put 1 cup of gypsum in the soil for best-root-growth. That growth was much better than mixing Tomato Tone NPK 4-3-6 (chicken manure & bone-meal) into potting soil.

Bone meal is better than chemical phosphorus because it's has both calcium & phosphorus, plus many trace elements. Chemical analysis of bone meal showed measurement in ppm, with 14% phosphorus and 23% calcium, plus many trace-elements, see below:

http://www.ingredients101.com/bone.htm

400 iron, 120 magnesium, 50 manganese, 300 sodium, 200 aluminum, 2,000 sulfates, 20 potassium, 100 zinc, 400 chlorides & plus many trace elements.

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 GRANULAR phosphorus applied on top, only move down 1 inch per year.

I don't use bone meal for roses in my pH 7.7 alkaline clay, bone meal needs slightly acidic pH (like potting soil plus rain-water) to release its nutrients.

NOTE: bone meal doesn't work for alkaline region like CA with alkaline tap water .. CA folks complained that Jobe's NPK 2-7-4 is lousy, but MG-soluble worked better (has acid).

This current year I ran out of Tomato Tone (with bone meal & chicken manure) and put some cheap Eco-scrap (dry-meat-fertilizer) into pots .. my 10 own-root roses come down with tons of nutrient-deficiencies from manganese, to zinc, boron, and copper .. but it's a good learning experience.

Below is my 1st year of own-root roses in pots. That's when I didn't put NPK 2-7-4 with bone-meal & chicken manure (high in boron, copper, and zinc) and roses had lots of problems: pale, blackspots. etc.

Straw: chicken manure seems to have a good combination of minerals in it but it's high salt content makes it too strong for the roses at times and they burst into un-natural growth and diseases. I am nowadays using chicken manure (along with river soil) as a layer in my compost. After having composted for 2-3 months along with kitchen waste (mostly peels of vegetable & fruits), it becomes something more useful in my view. Have you tried chicken manure in your compost?

best regards

Khalid: Fantastic tip !! Since last year I planned that for my 3 compost piles, but Menards stopped selling this giant bag of chicken manure for $8 .. will have to get that from a far-away feed-store. Walmart sells this tiny bag of chicken manure, not enough for my 3 compost piles.

My other option is to get FREE horse manure to layer with compost, but the horse manure is mostly sawdust & woodchips blended with small percentage of actual manure. It's a real-pain to load that horse-manure into my car, so I get FREE grass clippings (nicely bagged) from my neighbors for my compost pile.

Straw: It seems while you have availability of so many useful (and usefully prepared) items like azomite, kelp etc and many other organic fertilizers but many other things are not available to you in natural form. We have easy availability of pure manures here like cow dung (seasoned) and chicken waste. A friend of mine has a poultry farm and I get bags of seasoned chicken manure free of cost. I think even now 4-5 bags are still lying with me (20 kg bag). So far this compost is doing well for my roses and I guess I will keep using chicken manure in the compost and not directly in the roses beds / pots. I would like to see it for another 6 months how it works.

best regards

Has anyone ever tried soaking egg shells in rain water for calcium? I used to just bury my shells around the bushes and let them decompose naturally, but perhaps soaking them in acidic rainwater would make the calcium more quickly available. Thoughts or experiences?

My egg-shells in a shady & soaking wet (with rain) pile took 2 years to decompose. there's some site that said to use vinegar to dissolve egg-shell .. never try that before. I no longer put egg-shell into my compost .. takes too long to de-compose.

Yet more interesting info. I bought some alfalfa hay earlier in the season, but was afraid to use it when I noticed it said hay/grass. I was worried about grass seed in my beds. Maybe I'll try it in a small section and put the rest in my compost pile and over my greass.

I got some Plaintain weeds sprouting from the alfalfa hay, it's annoying until I saw the bunnies eating the plaintain weed. Alfalfa hay is cheap & slow to decay and buffers both rain and hot sun.

I tried grass clippings (free from the neighbors) but that doesn't work as well as alfalfa hay .. it's too acidic and grass doesn't have "growth-stimulating hormone". I have a raised tomato bed which I put 1 entire bag of 40 lb. alfalfa meal in 2012 .. plus 1 bag of 40 lb. gypsum over the last 2 years. Calcium plus alfalfa = aggressive growth & lots of leaves.

The tomatoes are green & lots of new growth, pic. taken Sept 16, 2016 in my zone 5a:

See above link that the major nutrients: nitrogen, potassium, phosphorus, and calcium are LESS AVAILABLE below pH 6. Rain is acidic at pH 4.5 in my Chicagoland. Liming helps to bring the pH to neutral for nutrients to be available. See below the map of rain pH across USA:

bump up for reference before our rainy fall (starts in mid-Sept.) here.

Fast tips: if your soil is compact clay with less rain, use gypsum.

If your soil is loamy & fluffy plus less rain then it has enough calcium.

If your soil is compact clay but high rain like mine, use agricultural lime (pelletized lime) with 100% calcium with 86% slow-released calcium carbonate & NO MAGNESIUM. Compact clay is already high in magnesium which glues soil together into clumps.

If your soil is loamy & fluffy but with high-rain, then use Garden lime/dolomite lime (has 12% magnesium and 22% calcium), the magnesium is to "glue" soil together, and the calcium is to raise the pH to offset acidic rain. Rain leaches out calcium.

Just when I thought I never use a 50lb of lime! Wonder if that is why rose growers in our area often lose them over our rainy, rainy winter? And I have enough gypsum for my cluster roots.