Nasturtiums are one of the most useful flowers for a Zone 13 garden: fast, generous and edible. Their round leaves and bright flowers in red, orange and yellow spill over pots, climb fences and fill gaps in beds, and both flowers and leaves can be eaten, with a peppery bite. With winter lows above 60°F and no frost at all, there is no cold to kill them — plant by heat and the wet and dry seasons instead.
Like cosmos, nasturtiums flower best in lean soil: rich soil and heavy feeding produce lush leaves and few flowers. Sow direct where they are to grow, thin to the final spacing, and let them scramble. This guide covers when to plant nasturtiums in Zone 13, with the soil, spacing, sun, water and care they need. Use the Zone 13 planting calendar to see what else to sow alongside it.
Zone 13 at a glance
USDA Zone 13 has average winter lows of above 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 13 guidance |
|---|---|
| Last / first frost | None — Zone 13 is frost-free year-round |
| Average winter low | above 60°F |
| Days to germination | 7–14 days |
| Days to maturity | 50–60 days |
| Sowing | Direct sow |
| Transplanting / planting out | Year-round (frost-free); best results in the planting window above |
| Harvest | Flowers 50–60 days after sowing/planting; pick regularly |
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Spacing | 8–12 inches |
| Water needs | moderate |
When to plant nasturtiums in Zone 13
In Zone 13, nasturtiums can be planted at any time of year because there is no frost — average winter lows are above 60°F and the zone is frost-free, so there is no last or first frost date to plan around. The best display comes from plants sown in the cooler months, roughly November to February, when nights are mildest and plants establish strongly, but a hot-season sowing will still flower well. Nasturtiums take 50–60 days to maturity, so work back from when you want flowers. Check your local extension service for the best planting windows in your area. Frost dates are zone averages — check your local extension service before you commit to a date.
Because nasturtiums self-seed freely in a frost-free climate, one planting can lead to volunteers for seasons to come — let a few flowers go to seed at the end of the display and seedlings will appear on their own. Keep a note of your sowing date and first flowers; after one season you will know exactly which weeks suit nasturtiums best in your own garden. Succession sow every few weeks through the cool season for a continuous display.
Starting nasturtiums in Zone 13
Nasturtiums are direct sown in Zone 13 — they dislike transplanting and do best sown where they are to grow. Soak the large seeds overnight if you like, then sow them in the bed, cover lightly, and keep the soil moist until seedlings appear — seeds germinate in 7–14 days. Thin seedlings to the final spacing once they are big enough to handle. If you must start indoors, use individual pots and transplant very young, before the roots fill the pot.
Give climbing types a fence, trellis or obelisk to scramble over, and let trailing types spill from pots and raised beds. Bush types stay compact and suit the front of a border. Nasturtiums need no coddling — warm soil, sun and a little water are enough to get them going, and they will cover bare soil fast, which also helps keep weeds down.
Soil, spacing, sun and water
Nasturtiums want full sun and lean, well-drained soil with a pH of 6.0–7.5. Do not dig in rich compost or feed heavily before planting: nasturtiums flower best in poor soil, and rich soil produces leaves at the expense of blooms. Space plants 8–12 inches apart, since crowded plants stay damp and invite disease. Mulch lightly to keep soil moisture even, but keep mulch away from the stems.
Nasturtiums need moderate water: water deeply and less often rather than lightly every day, water at the base in the morning so leaves dry before night, and check the soil a finger's depth down, watering when it feels dry there. Once established, nasturtiums are more drought-tolerant than most flowers, so do not overwater — soggy soil is worse for them than a dry spell. The watering calculator can help you work out a routine that keeps nasturtiums moist without waterlogging them.
Companion planting
Good companions for nasturtiums include lavender, marigolds, garlic and chives. Lavender and marigolds draw pollinators and beneficial insects to the bed, while garlic and chives are traditional companions said to deter aphids. The companion planting finder can suggest combinations for your whole bed. Nasturtiums themselves are famous companions: they act as a trap crop, drawing aphids away from other plants, and they sit well with tomatoes, cucumbers and squash in a mixed bed.
Use nasturtiums as a living ground cover around taller vegetables and flowers: they shade the soil, suppress weeds and attract pollinators, all while looking beautiful. Avoid planting nasturtiums where they will be heavily fed or watered for the sake of hungrier neighbours, since rich conditions spoil their flowering. A mixed sunny bed of nasturtiums, cosmos and marigolds makes a bright, pollinator-friendly display for months.
Pests and problems
The common pests and problems to watch for with nasturtiums are aphids, slugs and cutworms. Aphids love nasturtiums — which is exactly why gardeners use them as a trap crop — so expect colonies on shoot tips and wash them off with a strong jet of water, or leave them to draw aphids away from your other plants. Slugs chew ragged holes in leaves and young shoots, especially in damp weather, so look under pots and mulch in the morning. Cutworms can sever young stems at soil level, so protect fresh seedlings with a simple collar pushed into the soil around each stem.
In Zone 13's year-round warmth, pests never get a winter break, so check plants weekly rather than waiting for damage to show. Good air flow helps: space plants properly, avoid overhead watering late in the day, and remove spent flowers and damaged leaves promptly. Nasturtiums are generally trouble-free, and their biggest problem is usually too much food and water rather than any pest — if plants are lush and leafy with few flowers, stop feeding and let the soil dry a little between waterings.
Harvest and storage
Nasturtiums flower 50–60 days after sowing, and picking keeps them coming. Deadhead spent flowers every few days, and cut stems for the vase in the cool of the morning, choosing blooms that have just opened. Both flowers and young leaves are edible, with a peppery, watercress-like bite — pick them in the morning, wash well, and use them fresh in salads. Only eat flowers from plants you have grown yourself without sprays.
For the vase, cut stems in the morning, strip the lower leaves, and put stems straight into cool water. Let a few flowers go to seed at the end of the display if you want volunteers next season — nasturtiums self-seed freely in a frost-free climate, and seedlings will appear on their own in the bed. The round green seed pods can be pickled as a caper substitute. Pull out spent plants once they are finished and compost them.
Making the most of Zone 13
Zone 13's advantage is time: with no frost, you can grow nasturtiums for far longer than a single summer season. The trick is to sow direct in lean soil, pick flowers and leaves regularly, and keep a simple notebook of what you sowed and when it flowered — after one season you will have a record far more useful than any general guide. Related reading: cosmos share the same sunny, easy habits, and January in Zone 13 is a great month to plant. Marigolds in Zone 13 flower over the same long season and make good neighbours. Related reading: Cosmos in Zone 13 share the same habits, and January in Zone 13 is a great month to plant. For a planting plan tailored to your postcode, try the planting calendar by zip.
Frequently asked questions
When should I plant nasturtiums in Zone 13?
Nasturtiums can be planted year-round in frost-free Zone 13, but the best display comes from sowing in the cooler months, roughly November to February. Average winter lows are above 60°F, so there is no last frost date to count back from. Check your local extension service — these are zone averages, not exact dates for your garden.
How long do nasturtiums take to grow in Zone 13?
Seeds germinate in 7–14 days, and plants flower 50–60 days after sowing. In Zone 13, succession sow every few weeks through the cool season for a continuous display.
Can I grow nasturtiums all year in Zone 13?
Yes — Zone 13 is frost-free, so nasturtiums can be sown year-round, and they self-seed freely. Flowering is heaviest in the cooler months, and plants may slow in the hottest weeks, so plan your main display for the cool season.
What soil and spacing do nasturtiums need in Zone 13?
Nasturtiums need full sun and soil pH 6.0–7.5, spaced 8–12 inches apart. They flower best in lean soil, so do not feed heavily — rich soil produces leaves at the expense of blooms. Test your soil through your local extension service.
Are nasturtium flowers edible?
Yes — both flowers and young leaves are edible, with a peppery bite, and are often used in salads. Only eat flowers from plants you have grown yourself without sprays, wash them well, and pick them in the morning.