Growing geraniums in USDA Zone 12 is one of the easiest ways to keep colour in pots and beds for most of the year. Geraniums — the pelargoniums grown as bedding plants — love warmth and sun, and with average winter lows of 50 to 60°F and no frost at all, Zone 12 lets you grow them as a long-lived, almost permanent planting rather than a summer annual. They are at their best in pots and window boxes, where their tidy habit and long flowering season shine.
This guide covers when to plant geraniums in Zone 12, how to start them, and how to keep them flowering rather than going leggy. Geraniums take 70–90 days to maturity, so a planting this month is in flower within three months. Use the Zone 12 planting calendar to see what else to sow alongside them.
Zone 12 at a glance
USDA Zone 12 has average winter lows of 50 to 60°F and is frost-free year-round — there is no last or first frost date to plan around. Plan by heat and by the wet and dry seasons instead: heat lovers grow year-round, while cool-season crops only succeed in the coolest months. These are zone averages, not promises for any one garden, so check your local extension service for your area.
| Detail | Zone 12 guidance |
|---|---|
| Last / first frost | None — Zone 12 is frost-free year-round |
| Average winter low | 50 to 60°F |
| Days to germination | 7–14 days |
| Days to maturity | 70–90 days |
| Sowing | Start indoors, then transplant as sturdy seedlings |
| Transplanting / planting out | Year-round (frost-free); best results in the planting window above |
| Harvest | Harvest 70–90 days after sowing/transplanting; pick regularly |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 12–18 inches |
| Water needs | moderate |
When to plant geraniums in Zone 12
In Zone 12, geraniums can be planted at any time of year because there is no frost — average winter lows are 50 to 60°F and the zone is frost-free, so there is no last or first frost date to plan around. The best results come from planting in the cooler, drier months, roughly October to February, when new plants establish without the stress of the hottest, wettest weather — but a summer planting will still succeed if you water well and give afternoon shade. Because geraniums take 70–90 days to maturity, and because they can live for years in a frost-free climate, think of planting as the start of a multi-year plant rather than a single season. Check your local extension service for the best planting windows in your area.
Starting geraniums in Zone 12
Geraniums are started indoors from seed, then transplanted as sturdy seedlings — or, more commonly, grown from cuttings, which root easily and give you the named variety. Sow seeds shallowly in warm, moist compost; they germinate in 7–14 days. Give seedlings strong light and grow them on until they have several true leaves, then harden off for a week before planting out. For cuttings, take a healthy stem, let the cut end dry for a day, and push it into moist compost — roots usually form within a few weeks. Pinch out the growing tip once or twice while plants are young to encourage branching.
Soil, spacing, sun and water
Geraniums want full sun and well-drained soil with a pH of 6.0–7.0. They are not fussy about soil, but they do need drainage — geraniums hate wet feet, especially in warm conditions, and will rot quickly in waterlogged pots. Space plants 12–18 inches apart in beds, or a little closer in containers where you want a full look quickly. In Zone 12's heat, containers dry out fast, so check pots daily in summer, and feed lightly and regularly — geraniums in pots are hungry and will fade without feeding. The watering calculator will help you work out a watering routine for pots and beds.
Companion planting
Good companions for geraniums include lavender, marigolds, garlic, chives. In containers, geraniums pair well with trailing plants that spill over the edge while the geraniums fill the centre. Marigolds beside geraniums draw pollinators and beneficial insects, and the scented leaves of geraniums are traditionally credited with confusing some pests. Keep geraniums away from plants that need the same space — they resent being crowded and will go leggy if shaded by taller neighbours.
Pests and problems
The common pests and problems to watch for with geraniums are aphids, slugs, cutworms. Aphids cluster on shoot tips and buds and can be knocked off with water; slugs are a year-round problem in a frost-free climate and feed on young plants at night, so protect new plantings. Cutworms can sever young stems at soil level. In Zone 12's humidity, grey mould can follow wet foliage — water at the base, space plants for air flow, and remove faded flowers and yellow leaves promptly.
Harvest and storage
Geraniums flower 70–90 days after planting, and deadheading is what keeps them going: pick off spent blooms regularly, including the seed pod behind the flower, or the plant will stop flowering and set seed instead. Cut stems back by a third when plants get leggy and they will branch and flower again. Geraniums are grown for their flowers and scented leaves, not a harvest — enjoy them in beds, pots and baskets, and take cuttings from your best plants to keep the variety going. In Zone 12 a geranium can live for years, so replace only tired, woody plants.
Making the most of Zone 12
Zone 12 gives geraniums a long season and a warm start, and the reward is months of colour in beds and baskets. Start them indoors or from cuttings, plant out in the cooler months for the best display, feed lightly, deadhead often, and give summer plants afternoon shade. Related reading: Petunias in Zone 12 flower just as freely in the same pots and beds, and October in Zone 12 is a great month to plant out a new display.
Frequently asked questions
When should I plant geraniums in Zone 12?
Any time of year — Zone 12 is frost-free with winter lows of 50 to 60°F, so there is no last or first frost date to plan around. The best results come from planting in the cooler, drier months, roughly October to February. Check your local extension service — these are zone averages, not exact dates for your garden.
Can I grow geraniums all year in Zone 12?
Yes. Geraniums are heat lovers and Zone 12 has no frost, so they can live for years as a multi-year planting. Give summer plants afternoon shade and keep pots watered.
How long do geraniums take to grow in Zone 12?
Seeds germinate in 7–14 days, and the plants flower 70–90 days after planting. Cuttings are faster and give you the named variety.
What soil and spacing do geraniums need in Zone 12?
Geraniums need full sun and soil pH 6.0–7.0, spaced 12–18 inches apart in beds. Drainage is essential — they hate wet feet, especially in pots.