The Best Soil for Pansies

Drainage and Aeration

• The best soils drain well, so there is no standing water after rain or irrigation, but they also retain enough moisture so they do not dry out completely. Soil particles must also be loose enough so they don't compact, which causes poor aeration around the pansy roots. Loam and humus-rich garden soils work best, but heavy clay and sandy beds can be improved with amending. Working compost or peat moss into the soil improves both drainage and aeration in these poor soils. Work in a fresh layer of amendments before planting the pansies each year.

Moisture

• Plants require an even amount of moisture at all times to thrive. While good soil retains moisture longer, watering the pansies regularly ensures the soil bed never dries completely. Once weekly watering is usually sufficient, though in hot weather pansies may require more frequent irrigation. An organic mulch, such as wood chips, helps retain the moisture in the soil. The mulch also adds nutrients to the soil and improves the soil quality as it breaks down and decomposes.

Fertility

• Pansies require minimal fertilization to thrive. Even good loam soils require some additional fertilization to provide all the necessary nutrients to the pansy plants. Use a slow-release fertilizer in garden beds, reapplying it every four weeks while the pansies are actively growing. One tsp. of a balanced 10-10-10 fertilizer per square foot of bed provides enough soil nutrition for the pansies to grow and flower well.

Potting Mixes

• Container plants have slightly different soil needs than bedding plants. Soil in containers is more prone to compaction, so substitute a soilless potting mixture for garden soil. Most soilless mixes contain a combination of peat, compost, vermiculite and perlite. They aren't as heavy as garden soils, provide good drainage and aeration in the limited confines of a pot. Nutrients also wash out of pots more quickly than they do in garden beds due to frequent watering. Fertilize the plants every other week with a soluble balanced fertilizer.