Geranium Care and Problems

Location and Light

• Geraniums grow well in borders, beds, containers and hanging baskets. Plant or place geraniums where they receive six to eight hours of sun each day. Few or no blooms is often a symptom of insufficient sunlight. Geraniums in the Deep South, however, may need partial shade as a shield from the harsh afternoon sun and heat. As houseplants, geraniums need sufficient light. A sunny, south-facing window that receives eight hours of bright sunlight is an ideal location for geraniums. Fluorescent lighting provides supplemental light if a suitable indoor location isn't available.

Soil and Water

• Plant geraniums in soil that is medium to light with good drainage. Heavy clay soils benefit from the addition of organic matter, perlite or peat. Geraniums do best with a soil pH that is slightly acidic to neutral. After transplanting to the garden or container, water the geranium thoroughly and keep it watered well until it is established. Afterward, allow the soil to slightly dry out before watering again. Too much water causes root rot. However, don't allow the plant to wilt. Cycles of wilting and heavy watering stunt plant growth and cause the plant to lose its leaves.

Fertilizer Requirements

• Fertilize geraniums regularly but lightly. Heavy feeding of nitrogen cause excessive foliage growth but few flowers. Use a fertilizer solution that is 5-10-5 or equivalent. Indoor geranium plants do not much fertilizing. Use 5-10-5 fertilizers once during the growing cycle only.

Geranium Insects

• Aphids, whiteflies, caterpillars, mites, and slugs and snails are the main insects that attack geraniums. Geranium plants that are stressed due to improper growing conditions are most susceptible. Aphids, whiteflies and mites cause mottled and yellowing leaves by sucking the plant juices from the leaves. Spraying with an insecticidal soap rids the plant of all three pests. Caterpillars, slugs and snails are flower and foliage eaters that chew gaping holes into the plant. Deter slugs and snails by wrapping pots with copper string or placing copper edging around borders and beds. The copper creates an unpleasant chemical reaction on the pests' underbellies. To control caterpillars, apply BTK, Bacillus thuringiensi variety kurstaki; after ingesting it, the caterpillar becomes paralyzed, stops feeding and falls to the ground.

Geranium Diseases

• Leaf spot and blight often occur on geraniums from various types of fungi and bacteria. Spots ranging in different shapes, sizes and colors occur on the leaves, stems and shoots. Avoid leaf spot and blight by improving air circulation and water drainage. Remove and destroy infected plant parts and remove garden debris that may harbor the disease. Use Bacillus subtilis, a bacterium that kills harmful bacteria and fungicide.