How-to Guide
How to Grow Geraniums (Pelargoniums)
The short answer
Plant geraniums outside after all danger of frost is past and the soil has warmed, in well-drained soil where they get at least 4 hours of direct sun a day (Clemson Extension). Water regularly but let the soil dry between waterings, keep water off the foliage, and deadhead spent blooms to keep flowers coming all season.
Unlike most bedding annuals, geraniums are worth saving: before the first fall frost you can take cuttings, pot up whole plants for a bright window, or store them bare-root in a cool basement and cut them back hard at spring replanting (Clemson and University of Minnesota Extension).
When to Plant
Geraniums are tender. Clemson Extension says to set them out only after all danger of frost is past and the soil has warmed. Planting into cold soil stalls growth, so waiting a week past your average last-frost date costs you nothing.
If you overwintered plants or bought early, harden them off gradually and keep them protected on cold nights until frost risk is truly over.
Sun, Soil, and Water
Give geraniums a minimum of 4 hours of direct sunlight daily; in very hot areas, afternoon shade helps (Clemson Extension). University of Minnesota Extension likewise recommends a sunny spot with well-drained soil, in beds or containers.
Water regularly, allowing the soil to dry between waterings, but never let plants wilt or the leaves will yellow. Keep water off the foliage to limit disease. Corky spots on leaves (edema) are a sign of overwatering.
✔ Clemson's feeding schedule: about 1 pound of 10-20-10 fertilizer per 100 square feet at planting, then a water-soluble feed every 4 to 6 weeks through the season.
Deadheading for Nonstop Bloom
Snap or cut whole spent flower heads off the plant. Clemson Extension is direct about it: removing dead flowers prolongs flowering. Do it every time you water and the plant never wastes energy on seed.
Geraniums in Containers
Geraniums are classic container and window-box plants. Use a large pot with real drainage holes; if a potted geranium wilts frequently between waterings, it has outgrown its pot and should be repotted (Clemson Extension).
Overwintering: Three Ways to Save Them
- 1Cuttings — Take cuttings in fall and grow them on a sunny windowsill over winter — the least space-hungry method.
- 2Pot up whole plants — Dig plants before the first frost, pot them, cut them back, and keep them in a heated, bright spot indoors.
- 3Bare-root storage — The old-fashioned method: store plants bare-root in a cool basement (traditionally hung upside-down), then cut back about two-thirds of the top growth when replanting in spring (Clemson Extension).
Common Problems
- Bacterial leaf spot/blight — leaf spotting and stem rot; remove affected plants and avoid overhead watering.
- Botrytis (gray mold) — shows up in cool, moist conditions; deadhead and improve air flow.
- Edema — corky bumps on leaf undersides from overwatering; ease off the hose.
- Aphids, caterpillars (including budworms), mites, and whiteflies are the usual insect suspects (Clemson Extension).
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Clemson University HGIC — Annual Geranium (Pelargonium) — Plant after all frost danger with warmed soil; minimum 4 hours direct sun; watering, 10-20-10 feeding rate, deadheading, container care, three overwintering methods, and disease/pest list
- University of Minnesota Extension — Growing geraniums as annual flowers in Minnesota — Geraniums grow best in a sunny location with well-drained soil, in gardens and containers; can be overwintered via cuttings, potted plants, or bare-root storage in a cool, dry location