Nasturtiums are one of the most generous plants for a Zone 11 garden: bright flowers in orange, red and yellow, round lily-pad leaves, and a peppery flavour that makes them as useful in the kitchen as they are pretty in the garden. They grow fast, flower within two months, and thrive in poor soil where fussy flowers fail — which makes them perfect for a tropical garden.
Nasturtiums are also working plants: they lure aphids away from vegetables and draw in pollinators. The planting calendar hub shows how Zone 11 timing works month by month, and our guide to when to plant calendula in Zone 11 covers another edible flower that shares nasturtiums' easy-going nature.
Zone 11 at a glance
USDA Zone 11 covers the warmest, most tropical parts of the United States — Hawaii, southern Florida, Puerto Rico and the warmest coastal pockets. Winters are warm, with average winter lows of 40 to 50°F, and the growing season never really ends.
Zone 11 is frost-free year-round: there is no average last spring frost and no average first autumn frost. That means you plant by heat and by the wet and dry seasons, not by frost dates. These are USDA zone averages, not exact figures for any one garden — always check your local extension service and the forecast before planting.
| Detail | Zone 11 guidance |
|---|---|
| Average winter low | 40 to 50°F |
| Average last spring frost | Frost-free (no frost dates) |
| Average first autumn frost | Frost-free (no frost dates) |
| Days to germination | 7–14 days |
| Days to maturity | 50–60 days |
| Sowing | direct sow |
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Spacing | 8–12 inches |
| Water needs | moderate |
| Cold tolerance | tender |
When to plant nasturtiums in Zone 11
Plant nasturtiums in Zone 11 in the cooler months, roughly November through February, when mild temperatures let them flower at their best. In the hottest months they grow leggy, flower poorly and attract aphids, so the cool season is your main window. Seed germinates in 7–14 days in warm soil, and plants flower in 50–60 days, so an autumn sowing gives you blooms within two months. In the coolest corners of Zone 11, nasturtiums can flower for many months. Zone 11 is frost-free, so there is no last frost date; check your local extension service and the forecast before sowing.
Starting nasturtiums in Zone 11
Start nasturtiums from seed sown directly where they are to flower — they hate transplanting and grow fast from seed. Soak the seed overnight to speed germination, then sow it about an inch deep. Trailing varieties spill beautifully from baskets and over walls, while bush varieties suit edging and pots. Space plants 8–12 inches apart, and thin seedlings if they crowd. Nasturtiums also grow well in poor soil, so do not enrich the bed — rich soil grows leaves at the expense of flowers. The seed-starting calculator can work out your sowing dates.
Soil, spacing, sun and water
Nasturtiums need full sun and well-drained, poor to average soil with a pH of 6.0–7.5. They are famously unfussy — they flower best in poor soil, and rich soil makes them grow huge leaves with few flowers, so skip the compost and fertiliser. Water needs are moderate: water seedlings regularly until established, then water only in dry spells. Good drainage matters in Zone 11's rainy season, as nasturtiums hate wet feet.
Companion planting
Good companions for nasturtiums include lavender, marigolds, garlic and chives — but nasturtiums' best role is as a companion themselves. They are the classic trap crop: aphids prefer nasturtiums to almost anything else, so plant them near vegetables and the aphids will crowd onto the nasturtiums instead. They also draw in pollinators and their flowers are edible. The companion planting finder can suggest combinations for your whole garden.
Pests and problems
The common pests to watch for with nasturtiums are aphids, slugs and cutworms. Aphids love nasturtiums — that is partly the point, as they lure aphids away from vegetables — but if the infestation is heavy, wash them off with a strong jet of water or pull the worst-affected plant out entirely. Slugs and snails chew seedlings at night in the wet season; protect young plants with a ring of coarse grit. Cabbage white caterpillars can also chew the leaves, so check regularly. If you are unsure what is damaging a plant, the pest identifier helper can narrow it down.
Harvest and storage
Harvest nasturtiums 50–60 days after sowing, when the first flowers open. Pick flowers and young leaves in the morning, when they are fresh, and use them the same day — the flowers have a peppery, watercress-like flavour and brighten salads, while the leaves make a spicy garnish. Pick the seed pods while they are still green and pickle them as a substitute for capers. Deadhead spent blooms to keep plants flowering, and let a few flowers go to seed at the end of the season — nasturtiums self-seed freely in Zone 11.
Nasturtiums as a trap crop
A trap crop is a plant you grow deliberately to attract pests away from the crops you care about, and nasturtiums are the classic example. Aphids prefer nasturtiums to almost any vegetable, so a ring of nasturtiums around a vegetable bed acts as a decoy: the aphids crowd onto the nasturtiums, leaving your beans, squash and brassicas alone. The trick is to check the trap crop regularly — if it becomes heavily infested, pull it out and compost it before the aphids spread, or wash the aphids off with water. It is not a perfect system, but it is free, chemical-free, and it gives you edible flowers at the same time.
Frequently asked questions
When should I plant nasturtiums in Zone 11?
Plant in the cooler months, roughly November through February, when mild temperatures let them flower at their best. Seed germinates in 7–14 days and plants flower in 50–60 days.
Why are my nasturtiums all leaves and no flowers?
Usually soil that is too rich. Nasturtiums flower best in poor soil — skip compost and fertiliser, and give them full sun.
Are nasturtium flowers edible?
Yes — the flowers and young leaves have a peppery, watercress-like flavour and are used in salads. Only eat flowers you have grown yourself without sprays.
What is a trap crop?
A plant grown to attract pests away from other crops. Aphids prefer nasturtiums to most vegetables, so nasturtiums planted near a vegetable bed lure aphids away from your food crops.