Great ideas! Gonebananas, thumbs up for experimenting, please let us know the result. I have been pondering the solutions to my alkaline soil, with iron chlorosis my biggest concern.

The horse manure I got for my roses had lime (calcium carbonate) and pH of over 8. Stables use lime to deodorize their stalls. Lime is a potent fungicide and I don't have any black spots nor botrytis on my roses - that I like. However, lime also raises pH, with phosphorus got tied up in calcium, and my roses' blooms decreased. Horse manure is high in phosphorus but the lime makes it unavailable.

My question is: does lime (calcium carbonate) moves with water, or does it stays where applied? Nitrogen moves withh water, but phosphorus and potassium stay put where applied (from EarthCo. booklet). Can I still keep the horse manure as mulch to prevent roses' fungal diseases, but use an ACID SOLUBLE fertilizer to break down the phosphorus in my fertile clay soil?

My garden pH of 7.7 give tons of blooms, except for roses. Alkaline clay soil is fertile with lots of phosphorus for plants thriving in the pH of 7.5 to 8.5 zone, such as Begonis, Callendula, Clemantis, Foxglove, Marigold, and Geraniums.

It's the picky roses that do best at pH 6.5 that I have to fix the soil. I need help with this: Is lime soluble and moves with water like nitrogen, or does it stay put where's applied like phosphorus and potassium? Many thanks for any info.

My question is: does lime (calcium carbonate) moves with water, or does it stays where applied? Nitrogen moves withh water, but phosphorus and potassium stay put where applied (from EarthCo. booklet).

In most cases, calcium and magnesium are relatively stable - more so than potassium, in fact. This has to do with the strength of their (positive) charge and how strongly they attach to the (negative) charge of soil particles.

Hi fortyonenorth: I'm happy to hear your verdict on lime ... which means I'll mulch my roses with horse manure so I won't have to spray my roses with chemical fungicides. I tried to dissolve calcium carbonate in water with no luck. I checked on Ferrous Sulfate and found it's soluble in water. Does that mean I can be lazy, that is, sprinkle 1 teaspoon of soluble fertilizer around roses and water them in? It's a hassle to dissolve soluble fertilizer (with iron) in a bucket to water roses. I would like to hear more verdicts to enable the-lazy-gardener syndrome. Thank you.

Calcium carbonate is not very soluble straight-out in water but becomes much more soluble below the ground surface where dissolved carbon dioxide is greatly enriched from organic-matter decomposition and root respiration. The dissolved CO2 chemically reacts with the calcium carbonate thus greatly increasing its dissolution.

I am not sure how readily the complexed phosphorus is released once the carbonate is gone.

Thank you, goonebananas for the info. I checked on ferrous sulfate and found the below info.

"Consider an iron sulfate drench if pH is not coming down below 6. If uptake of ammonium is not lowering media-pH quickly enough (a realistic target is 0.5 pH units within a week), a drench of iron sulfate (also called ferrous sulfate or FeSO4) can be applied to lower media-pH within a day or two. Iron sulfate can be purchased from agricultural suppliers.
Iron sulfate is moderately acidic and has the benefit of adding iron (20.8 percent by weight). The material is highly soluble at water pH below 6.0, and it can be applied as a drench at 2 pounds/100 gallons (2.4 g/L)."

Other info. given by the below link: "The recommended application rate for an iron drench is 5 ounces per 100 gallons of either Iron-EDDHA (several brands including Sprint 138 are available from many nursery suppliers), which provides 22.5 ppm iron, or Iron-DTPA (for example, Sprint 330), which provides 37.5 ppm iron). The letters EDDHA or DTPA are important because the iron form affects solubility at high pH (Figure 3). Iron forms decrease in solubility above pH 7 in the order from EDDHA (best) > DTPA > EDTA > sulfate (worst)."

That sounds confusing, so I'll order Neptune fish soluble fertilizer with Iron of 101 ppm.

Here is a link that might be useful: High pH problems and drenching with iron in green house

In many feed and seed stores, ferrous (iron II) sulfate is sold as "copperas." I have encountered otherwise good stores that were unaware that they even sell ferrous sulfate but had it on their shelves in this other name. Make SURE you are NOT getting any copper compound. Copper sulfate is also sold in these stores and would be near-instant death to your plant's roots if applied anywhere near the rates used for iron.

Is there a difference between ferrous (iron II) sulfate and iron sulfate?

Hi gonebananas: thanks for the info. about ferrous sulfate at the feed store, where I'll get alfalfa meal. I checked the price, it's very good at $5 for 1 lb. versus Neptune Fish Emulsion quite expensive and it attracts animals. I finally find info. that's easy to follow:

"If your soil is not naturally acidic, mix in 1/2 to 3/4 peat moss with the planting soil. At the same time, mix in thoroughly 6oz. (12 teaspoons) of Ferrous Sulfate to a 3' x 3' area for each plant. If you want to change PH 6.5 to PH 5.5, apply 12 oz. In a 3' x 3' area around the plant and water well. Keep plants well watered"

My question: Can ferrous sulfate be mixed with vinegar (to lower my water at pH of 8 down to 6, where ferrous sulfate dissolves) - then use this solution to water rhododendrons and azaleas? Thank you in advance.

More good info. on iron sulfate: In horticulture it is used for treating iron chlorosis. Although not as rapid-acting as iron chelate, its effects are longer-lasting. It can be mixed with compost and dug into to the soil to create a store which can last for years.

The above sounds good, but does iron sulfate need a pH of below 6 to be dissolved?

Fortyone north asked the question about the difference between the 2 terms. Here's the answer I found, "Iron forms two types of sulfates, Ferrous sulfate FeSO4 and Ferric sulfate Fe2(SO4)3 , Ferrous sulfate is easily soluble in normal water and Ferric sulfate may be dissolved in water by adding a little amount of sulpuric acid."

I'll look for ferrous sulfate as gonebananas suggested, dissolve this in water with some used lemon rinds, then water my 2 particular rhododendrons to see if that will fix the cholorosis (planted in EarthGro topsoil, pH of 8 - and I forgot to put in peat moss this year!)