Zone 13 is the hottest USDA zone and the only one that is frost-free year-round, with average winter lows above 60°F. There is no last spring frost and no first autumn frost to plan around, so in Zone 13 you plant by heat and by the wet and dry seasons, not by frost. The limits on what grows are heat, humidity, rain and pests rather than cold. All numbers below are published ranges, not promises for your garden: check your local extension service before you plant.
Arugula is the fastest salad green you can grow: seed to salad in about a month, with a peppery flavour that no shop-bought bag can match. In Zone 13 that speed is essential, because arugula bolts faster than almost any other green once heat arrives. Sow it in the coolest months, give it a little shade, pick it young, and it is one of the most rewarding crops in the tropical garden.
Zone 13 timing for arugula
The table below is the whole plan in one place.
| Step | Zone 13 timing |
|---|---|
| Average winter low | Above 60°F |
| Last spring frost | None — frost-free year-round |
| First autumn frost | None — frost-free year-round |
| Best planting window | Coolest months only, roughly November to February |
| Start indoors | Not needed — sow direct where plants will grow |
| Direct sow outdoors | Sow direct the coolest months, roughly November to February |
| Days to germination | 7–10 days |
| Days to maturity | 30–45 days |
| Cold tolerance | hardy |
When to sow arugula in Zone 13
Sow arugula in the coolest months, roughly November to February, in small batches every two weeks. It matures in about four to six weeks, so succession sowing is easy and worthwhile. Stop sowing as soon as the weather warms — in hot weather arugula can bolt within days of germinating, and the leaves turn bitter almost overnight.
Starting arugula: indoors or direct sowing
Arugula is direct-sown: scatter seed thinly, cover very lightly, and keep the seed bed damp until germination, which takes about a week. Thin seedlings to the spacing in the table, and eat the thinnings. Sow in a spot that gets morning sun and afternoon shade, which buys you an extra week or two before bolting. Use the seed spacing calculator to plan your rows before you sow.
Soil, spacing and sun
Arugula needs full sun. Space plants 6–8 inches apart — crowded plants compete for light, water and air, and disease spreads faster between touching leaves in humid tropical air. Arugula is not demanding, but it does best in loose, compost-rich soil that holds moisture. Work compost into the bed before sowing and keep the soil damp — dry soil makes leaves hot and tough. A light mulch after seedlings are up helps, but keep it away from the tiny stems.
Watering arugula in Zone 13
Water needs are moderate, but arugula is shallow-rooted and dries out fast in tropical sun. Water lightly and often, preferably in the morning, and do not let the bed dry out between waterings. Even moisture keeps the leaves mild; drought makes them fiercely peppery and tough.
Companion plants
Good companions for arugula include marigolds, basil, onions, lettuce. These are the companions listed for this crop in standard horticultural references: they share similar needs, and some, like marigolds, are traditionally planted to help confuse or deter pests. Plant companions in the same bed or nearby, not in a separate corner of the garden, so they actually share the space. Avoid planting heavy feeders that will compete for the same nutrients in the same spot.
Common pests and problems
The pests to watch for are cabbage worms, aphids, flea beetles and slugs. Flea beetles are the main problem, peppering leaves with tiny holes — row cover over the bed from sowing onwards is the most reliable fix. Slugs nibble seedlings on damp nights, so keep the bed tidy and check after rain.
Harvest and storage
Pick arugula young, starting about a month after sowing, by cutting outer leaves and letting the centre regrow. Pick in the morning when leaves are crisp and mild, and use them the same day. Once the plant sends up a flower stalk, the leaves turn bitter — harvest what is left and sow a fresh batch. Use the harvest date calculator to work out a harvest window from your sowing date.
Succession and rotation in Zone 13
Succession sowing works in Zone 13, but only inside the cool season: sow a small batch every two to three weeks while the weather stays mild, so the harvest stretches out instead of arriving all at once. Once heat builds, stop sowing — a late batch will bolt before it is worth picking. Rotate crops so arugula does not follow another Brassicaceae family crop in the same bed next season. Keep notes on what you sowed and when: in a climate with no frost dates, your own records are the most useful planting guide you will have for the next cool season.
Related Zone 13 guides
More Zone 13 guides: Mustard Greens in Zone 13 and the same crop in a cooler zone, Arugula in Zone 11. The January in Zone 13 guide shows what else to plant in that month, and the planting calendar hub brings all the Zone 13 guides together.
Frequently asked questions
When should I plant arugula in Zone 13?
Sow arugula in the coolest months, roughly November to February. Zone 13 is frost-free with winter lows above 60°F, so there is no last or first frost date to work from — plant by the cool season, not by frost. Check your local extension service for the best sowing weeks in your area.
Why is my arugula so bitter?
Usually heat, drought or age. Arugula grown in the cool season with even water is mild and nutty; the same plant in hot, dry weather turns fiercely peppery. Pick leaves young, water evenly, and give plants afternoon shade.
How do I keep arugula going longer in Zone 13?
Sow small batches every two weeks through the cool season, give plants afternoon shade, water little and often, and harvest young. There is no way to keep arugula going through tropical summer — plan for a cool-season-only crop and enjoy it while it lasts.
What soil and spacing do arugula need?
It needs full sun, soil pH 6.0–7.0, and spacing of 6–8 inches between plants. Work compost into the bed before planting and test the soil rather than guessing the pH.