Growing nasturtiums in USDA Zone 12 is a fast, generous project: these are heat lovers that thrive in tropical sun, and with average winter lows of 50 to 60°F and no frost at all, Zone 12 lets you grow them year-round. Nasturtiums do double duty in the garden — bright flowers, edible leaves and blooms with a peppery bite, and a reputation as a trap crop that draws aphids away from vegetables. They are also famously unfussy, flowering best in poor soil.
This guide covers when to plant nasturtiums in Zone 12, how to start them, and how to use them as both a flower and a vegetable-garden helper. Nasturtiums take 50–60 days to maturity, so a sowing this month is in flower within two 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 | 50–60 days |
| Sowing | Direct sow where it is to grow |
| Transplanting / planting out | Year-round (frost-free); best results in the planting window above |
| Harvest | Harvest 50–60 days after sowing/transplanting; pick regularly |
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Spacing | 8–12 inches |
| Water needs | moderate |
When to plant nasturtiums in Zone 12
In Zone 12, nasturtiums 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 sowing in the cooler, drier months, roughly October to February, when seedlings establish in gentler conditions — but a summer sowing will still succeed if you keep the seedbed moist. Because nasturtiums take 50–60 days to maturity, sow in succession every few weeks for a continuous display. Check your local extension service for the best planting windows in your area.
Starting nasturtiums in Zone 12
Nasturtiums are direct-sown where they are to grow, because they dislike root disturbance and their seedlings are fragile. Sow the large seeds about an inch deep in warm, moist soil; they germinate in 7–14 days. Soaking the seeds overnight can speed germination, and nicking the seed coat helps too. Thin seedlings to their final spacing once they have a few true leaves. Climbing types need a trellis, fence or string to scramble up, while bush types are happy at the edge of a bed or spilling from a pot.
Soil, spacing, sun and water
Nasturtiums want full sun and are famously unfussy about soil, thriving in a pH of 6.0–7.5 as long as it drains. Do not over-feed them: rich soil produces big leaves and few flowers, while poor soil gives compact plants covered in blooms. Space plants 8–12 inches apart, and give climbing types a support to scramble up. In Zone 12's heat, a light mulch keeps the roots cool and the soil evenly moist, but keep mulch away from the stems. The plant spacing calculator will help you work out how many plants fit your bed.
Companion planting
Good companions for nasturtiums include lavender, marigolds, garlic, chives. Plant them beside tomatoes, cucumbers and squash, where they act as a trap crop: aphids prefer nasturtiums to the vegetables, so the pests gather on the nasturtiums and leave the crops alone. Check the nasturtiums regularly and remove badly infested leaves, and you will have protected the vegetables with a flower. They also draw pollinators to the whole garden.
Pests and problems
The common pests and problems to watch for with nasturtiums are aphids, slugs, cutworms. Aphids are the point, in a sense — nasturtiums are planted to attract them away from other crops — but if the infestation gets heavy, knock them off with water or remove the worst leaves. Slugs feed on young seedlings at night in a frost-free climate, so protect new sowings, and cutworms can sever young stems at soil level. Nasturtiums are generally tough, and a healthy plant in full sun usually outgrows minor damage.
Harvest and storage
Nasturtiums flower 50–60 days after sowing, and the harvest is twofold: flowers and leaves. Pick young leaves and flowers in the morning for salads, where their peppery bite adds flavour and colour — only eat flowers you have grown without sprays. Pick flowers regularly to keep new ones coming, and let a few flowers set seed if you want to collect them: nasturtium seed can be pickled as a caper substitute. In Zone 12 a nasturtium bed can flower for months — pull tired plants and re-sow rather than trying to nurse them back.
Making the most of Zone 12
Zone 12 suits nasturtiums perfectly: warmth, sun, a season that never ends, and soil that does not need to be rich. Sow direct, give them sun and space, do not over-feed, and let them work as a trap crop in the vegetable beds as well as a flower in their own right. Related reading: Calendula in Zone 12 is another edible flower for the same beds, and October in Zone 12 is a great month to start a new bed.
Frequently asked questions
When should I plant nasturtiums 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 sowing 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 nasturtiums all year in Zone 12?
Yes. Nasturtiums are heat lovers and Zone 12 has no frost, so they can be sown and flowered year-round. Sow in succession every few weeks for continuous colour and leaves.
How long do nasturtiums take to grow in Zone 12?
Seeds germinate in 7–14 days, and the plants flower 50–60 days after sowing. Pick leaves and flowers regularly to keep new ones coming.
What soil and spacing do nasturtiums need in Zone 12?
Nasturtiums need full sun and soil pH 6.0–7.5, spaced 8–12 inches apart. They flower best in poor soil — do not over-feed, or you will get leaves at the expense of flowers.