Things You'll Need
Hose, standard or soaker
Miracid is widely used as a way to fertilize acid-loving plants, such as azaleas and rhododendrons. It contains high levels of iron, to guard against deficiencies. Arborvitae doesn't require a fertilizer specified for acid-loving plants, as it does well in both alkaline and acid soil. If your arborvitae is planted among your azaleas, near your blueberries or hydrangeas, go ahead and fertilize it with the Miracid. Fertilize the arborvitae in spring.
Fill a bucket half full with water. Pour in 1 tablespoon of Miracid, then finish filling the bucket with water. Swirl it gently until the crystals are dissolved.
Pour the Miracid solution over the soil, 6 inches from the base of the arborvitae. Circle the plant, pouring the solution slowly as you do so.
Water the soil around the arborvitae, to a depth of 10 inches. Apply the water slowly, such as with a soaker hose or a standard hose set to a trickle.
Although the product’s label suggests applying Miracid every week to two weeks during the growing season, arborvitae does not require a lot of fertilizer. An annual application is sufficient.