Mixing Epsom Salt with Milorganite for Flower Gardens

Epsom Salt Effectiveness

• Epsom salt, another name for magnesium sulfate, treats magnesium deficiency in plants. Magnesium deficiency shows up as a yellowing between the veins on a plant's leaves. A shortage of magnesium in soil can be to blame, or other factors can inhibit a plant's magnesium uptake. If your flowering plants show signs of magnesium deficiency or a soil test confirms your soil lacks magnesium, then using Epsom salt can help ailing plants. According to University of Washington Extension horticulturist Dr. Linda Chalker-Scott, however, no scientific evidence exists that Epsom salt enhances flowering unless nutrient-deficient flowering plants need a magnesium boost.

Milorganite Benefits

• Widely used in turf management, Milorganite is a slow-release fertilizer created from treated sewage sludge. It is a 5-2-0 fertilizer, which means it contains 5 percent nitrogen, 2 percent phosphorus and zero percent potassium. Because nitrogen promotes leafy growth instead of blooms, Milorganite's nitrogen-heavy balance best suits foliage plants and turf. Sewage sludge originates from living matter, and so Milorganite is considered organic fertilizer. The U.S. Department of Agriculture's Organic Production and Handling Standards, however, prohibit the use of sewage sludge products by organic growers, but Milorganite is approved by the U.S. Environmental Protection Agency for home garden use.

Flower Garden Fertilizers

• Complete fertilizers contain all three main plant nutrients: nitrogen, phosphorus and potassium. The University of Connecticut Cooperative Extension System's Soil Nutrient Analysis Laboratory prescribes complete fertilizers for flower garden use. Because phosphorus promotes blooming, flower garden fertilizers should have phosphorus equal to or higher than their nitrogen content. Fertilize perennial flower gardens' soil in early spring with a second application as summer begins. For example, broadcast a granular 5-10-5 or 5-10-10 fertilizer at a rate of 2 pounds per 100 square feet of soil surface. Wear gloves, protective clothing and eye-wear. Follow your product's instructions, and keep children and pets clear from the area.

Mixes and Matches

• Although Epsom salt and Milorganite can be mixed, consider what you can expect from your expense and work. Unless magnesium deficiency is an issue in garden soil, Epsom salt won't provide a substantial benefit. Too much of it can cause nutrient imbalances and contaminate water that moves through the soil. Milorganite adds nitrogen at a rate more than double its phosphorus. That could lead to lots of foliage growth but few flowers. It also lacks potassium, which is a necessary part of a complete fertilizer that supports overall growth and root development. Flower gardens need proper nutritional balance in order for their flowering plants to reach their full potential. Anything less could limit their bountiful blooms.