Beautiful roses, Strawberryhill. Thanks for the info on pine bark, tannin and calcium.

I hadn't realized that pine bark contained tannin.

That's interesting about calcium and cell membranes. Calcium is a micronutrient for roses, good to know how it works for the plant.

Thank you, it's so refreshing to hear your kind words and vast experience of growing hundreds of rose for decades in your zone 5a NY garden.

Mike_Rivers, a retired chemist from MI, stated that he's trying spraying with milk. Milk is high in calcium, so it acts like a foliar spray to strengthen leaves. Milk has salt, which inhibits fungal growth.

Applying gypsum (calcium sulfate) in my pots make a big difference, they are perky, thicker leaves, and less watering.

Looking at the 2 bouquets picked today, Sept 10, at 93 degrees ... I can tell you which one is fertilized with soluble calcium (gypsum). The blooms have firmer petals, more photogenic, and last longer in the vase with added calcium. They are: tiny dark pink Yves Piaget's child, Pink Peace and mauve Wise Portia (both calcium and potassium added).

There are several studies that showed plants can withstand heat and drought better with calcium and potassium.

This post was edited by Strawberryhill on Sat, Oct 5, 13 at 12:01

I found a horticultural abstract entitled, "Applications of Potassium silicate decrease black spot infection in rose Fuschia Meidiland". The conclusion: "The results indicate that using potassium silicate in irrigation water may be a useful component of a disease management system."

Potassium silicate is a pH up, it makes the soil alkaline and imparts silicon to the leaves. Potassium silicate is sold as "Rhino Skin" for $7 at Planet-Natural .. I wonder how they extract that from Rhino Skin?

http://www.planetnatural.com/product/rhino-skin-potassium-silicate/

I googled "Foods highest in silica" and found this info: "one of the best food sources for silica is oats. A breakfast muesli made with raw soaked oats eaten daily supplies lots of silica. (Guess why horses fed with oats are so strong and have such shiny coats?) Without silica there would be no lustre to our hair; we would have brittle nails, rough and itchy skin and no elasticity in our connective tissues."

I got 42 oz, or 2 lb. of oats for $2 at the grocery store. I grounded that up in a coffee grinder, and fertilized Bolero, very pleased with the results ... cheaper than Rhino skin!

Here is a link that might be useful: Horticultural abstract on potassium silicate

This post was edited by Strawberryhill on Sun, Oct 6, 13 at 11:47

Oats is high in manganese ... most deficient in my alkaline clay soil. My clay is tested exceedingly high in magnesium ... magnesium is what makes clay sticky. Here's an excerpt from the below chart on nutritional deficiency, taken from a cannabis site. Note: I don't do drugs, I only grow roses, but the site is helpful in identifying nutritional deficiencies:

"MANGANESE (Mn) Necrotic and yellow spots form on top leaves. Mn deficiency occurs when large amounts of Mg (magnesium) are present in the soil. Foliar feed with any chemical fertilizer containing Mn."

POTASSIUM (K) Affected plants are usually tallest and appear to be most vigorous. Necrotic spots form on lower leaves. Red stems. Leaves appear pale or yellow. Add chemical fertilizer containing K."

Here is a link that might be useful: Nutritional deficiency table

LOL, Straw! Great information source!

No, seriously, it IS a good table. Just laughed when I saw the source. Some of the most useful info. I've found on all sorts of growing things comes from such sites. All the stuff on using cloners, hydroponic gardening, growing supplements--you name it--the pot growing sites are the best.

Hi Bluegirl: I'm glad to hear from you, thanks. I wish I had seen the above info., before killing my rhododendrons with iron sulfate. Later I found an Illinois field study with pine trees, reporting that my area is deficient in manganese (diffused yellowing), rather than iron (well-defined green veins on yellow leaves). Deficiency of manganese often result from compact, poor drainage clay.

What I should had done was to buy $2 worth of wheat bran or rice bran, highest in manganese. See info:

"Wheat bran provides 6.7mg (334% DV) per cup, rice bran provides 16.8mg (838% DV) per cup, and oat bran provides 2.1mg (106% DV) of manganese per cup. "

.... or better yet I should had dug up my acid-plants and fixed my heavy clay with coarse sand and coarse pine barks (pH 4.5), after the acid-fertilizer and the iron sufate failed.

Here's a picture of manganese deficiency in heavy & compact alkaline clay. It's very common in my pH 7.7 clay:

http://www.ipm.iastate.edu/ipm/hortnews/2006/8-23/deficiency.html

Here is a link that might be useful: Top 10 foods highest in manganese

This post was edited by Strawberryhill on Tue, Nov 5, 13 at 17:00