Persephone wrote:
OK, I got some sulfur today - was going to email him to see if it
was the right kind, but Stephen, I hope you're seeing this?
Product is called "Sulfur Dust", by Lilly Miller. 90% sulfur, 10%
inert ingredients.
What's confusing to me is that it's sold as a fungicide/insecticide.
"For use on roses, grapes, citrus fruits, berries,nuts, vegetables,
flowers, shrubs, trees. Controls powdery mildew, rust, scab, mites."
Doesn't say anything about acidifying the soil. Only mention of
flowers is dusting or spraying foliage.
They said I could return it if it wasn't the right thing.
Yes, this sulfur is just fine. It may be a WP (Wetable Powder), but in
any case it is powdered sulfur.
So -- can I in fact mix this with the soil of the azalea?
You have to sprinkle it on top of the soil. If you mix it in to the soil
you destroy the shallow roots of the azalea.
It is best to push back the mulch and then sprinkle it on the soil, then
put the mulch back. Obviously you need to have the soil tested and
determine the pH of the soil before you use it. The dosage is:
Present pH = 8 use 5.5 pounds per 100 sq. feet
Present pH = 7.5 use 4.5 pounds per 100 sq. feet
Present pH = 7 use 3.5 pounds per 100 sq. feet
Present pH = 6.5 use 2.5 pounds per 100 sq. feet
Present pH = 6 use 1.0 pound per 100 sq. feet
To convert to 1 square foot, divide by 100. So for every pound on the
chart use 4.5 grams per square foot.
A teaspoon of 90% sulfur contains about 3.5 grams of sulfur.
A tablespoon of 90% sulfur contains about 11 grams of sulfur. So:
Present pH = 8 use 2 tablespoons of 90% sulfur per sq. feet
Present pH = 7.5 use 1 tablespoon & 2 teaspoons of 90% sulfur per sq.
feet
Present pH = 7 use 1 tablespoon & 1 teaspoon of 90% sulfur per sq. feet
Present pH = 6.5 use 1 tablespoons of 90% sulfur per sq. feet
Present pH = 6 use 1 teaspoon of 90% sulfur per sq. feet
Or spray its foliage?
There are chelated iron foliage sprays that can be used temporarily
until the soil pH gets corrected. It takes time for powdered sulfur to
adjust the pH. The sulfur is treating the soil, not the azalea. The
reason you are treating the soil is because an alkaline soil will not
give the azalea the proper nutrients.
The chelated iron foliage spray is a temporary way to get the correct
nutrients to the azalea until the soil gets where it should be.
I know many on this NG are hostile to Miracle-Gro-type products, but
they do make an acid fertilizer which I've never used. Is this
something to consider?
Miracid/Miracle-Gro Water Soluble Azalea Camellia Rhododendron Plant
Food is a water soluble, nitrogen-rich powder and that is a very poor
choice for outdoor azaleas. It is OK for azalea house plants and green
house azaleas.
Miracle Grow does have a dry slow release azalea food:
Miracle-Gro Shake 'n Feed Continuous Release Azalea, Camellia,
Rhododendron Plant Food is a better choice for outdoor azaleas, but it
is plastic coated chemicals.
The best choice is HollyTone. It is mostly organic natural materials
that cater to the modest requirements of azaleas.
Now is not a good time to fertilize except with a chelated iron foliage
spray.
Some chelated iron foliage sprays a
Bonide Liquid Iron
Lilly Miller IronSafe
--
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Visit my Rhododendron and Azalea web pages at:
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Cheers, Steve Henning in Reading, PA USA Zone 6