Soil and Bed Preparation for Growing Dahlias (Page 2)

Dahlias prefer soil that has a pH of 6.50 continued…

The pH can also be lowered using chemicals that result in two amendments to the soil. Two examples, Ammonium Sulfate and Iron Sulfate follow: Ammonium Sulfate 21N; 24S — When put in the soil ammonium sulfate releases nitrogen (21%) and sulfur (24%). Thus the soil gets fertilized and at the same time the pH is lowered. This would be a good choice if the pH needed to be lowered at the same time as a nitrogen fertilizer was needed.Before using these dual function chemicals, calculations to determine the respective amounts of each substance that one will receive should be done. For example, if the pH of a very heavy clay soil was eight and the intent was to lower the pH to seven, 25 lbs. of sulfur would be needed for every 1,000 square feet. To get 25 lbs. of sulfur from this particular ammonium sulfate approximately 100 lbs. of ammonium sulfate would be required. The amount of sulfur in 100 lbs. of this ammonium sulfate is 24% x 100 lbs. = 24 lbs. At the same time, however, 21 lbs of nitrogen would be produced for every 1,000 square feet of soil (21% x 100 lbs of ammonium nitrate). That would be about three times a normal application of nitrogen. Will dual purpose chemicals of this sort are useful, attempting to use them in place of single purpose chemicals will result in serious problems.Note the two pictures on the right. The same chemical can come in different colors as well as different forms (powders, granules, liquids). Keep them well marked when removing them from their original container.	Ammonium Sulfate — 21% N — 24% S
	Ammonium Sulfate — 21% N — 24% S
Iron Sulfate – 31% Fe — When put in the soil releases iron (31%) and some unspecified amount of Sulfur. Any attempt to use this iron sulfate to reduce the pH, would result in toxic levels of iron in the soil.Note the two pictures on the right. Two similar chemicals but looking quite different. Fertilizers and other agricultural chemicals can not necessarily be identified by their color or form.Iron Sulfate-Copperas is said to be faster acting than Iron Sulfate 31.	Iron Sulfate — 31% Fe min.
	Iron Sulfate-Copperas — 21% Fe min.

Dahlias prefer soil that has a pH of 6.50 continued…

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