BD #508 can be used for soil or foliar applications, especially when conditions are too wet. It helps discourage fungal disease. One unit of dried herb makes 2 gallons of fresh tea, enough to treat one acre, or 10 gallons of fermented tea.
Fresh Tea Instructions for BD #508 Bring one ounce of horsetail herb to a boil in one quart of water. Allow to cool. Strain and dilute adding 2 gallons of water. Stir vigorously for 20 minutes. Apply using a fine mist spray to the foliar parts of targeted plants.
Fermented Tea Instructions for BD #508 Bring one unit of horsetail herb to boil in one gallon of water and simmer for one hour. Let cool and transfer to a crock or other storage container with a loose fitting lid. Store this in a cool place, e.g. basement, and allow to ferment 10 to 14 days, until the fermented tea has a strong sulphuric aroma. Strain the remaining herb particles out, fill the tea in a glass jug, and store it in a cool dark place until ready to use. It can be stored 6 or more months without losing effectiveness. To use, add 1/2 gallon of fermented tea to 4 1/2 gallons water, stir vigorously for 20 minutes, and use to treat up to 1 1/2 acres. One unit of horsetail can thereby treat up to 3 acres with as powerful effect as can be achieved by the fresh tea recipe on only one acre. Ratio for diluting is one part fermented tea to 9 parts water.
The fermented BD #508 most likely should be applied as a soil spray, whereas the fresh tea version is most likely the form to use as a foliar spray.