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.
Scallions, also sold as green onions or spring onions, are the fastest allium you can grow and one of the most forgiving cool-season crops for Zone 13. They are ready in about two months from seed, they take up almost no space, and they can be cut and allowed to regrow. Their only real demand is cool weather: sow them in the coolest months and they are generous; sow them in summer heat and they bolt before you can use them.
Zone 13 timing for scallions
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 | 7–14 days |
| Days to maturity | 60–70 days |
| Cold tolerance | hardy |
When to sow scallions in Zone 13
Sow scallions in the coolest months, roughly November to February, in small batches every two weeks so you always have a fresh row coming on. Because they mature quickly, a late cool-season sowing still has time to finish, which makes them one of the last cool-season crops worth sowing. Stop sowing once daytime heat builds, and start again when the cool season returns.
Starting scallions: indoors or direct sowing
Scallions are direct-sown: scatter seed thinly in a shallow drill, cover lightly, and keep the seed bed damp until germination. They germinate in about a week to ten days. Thin seedlings to the spacing in the table so each plant has room to thicken, or sow in a band and harvest the thinnings as baby scallions — nothing is wasted. Use the seed spacing calculator to plan your rows before you sow.
Soil, spacing and sun
Scallions needs full sun. Space plants 2–3 inches apart — crowded plants compete for light, water and air, and disease spreads faster between touching leaves in humid tropical air. Scallions are not fussy, but they do best in loose, compost-rich soil that drains well. Work compost into the top few inches before sowing, and keep the bed free of weeds, because young scallions are easily smothered. A light mulch after seedlings are a few inches tall holds moisture without burying them.
Watering scallions in Zone 13
Water needs are moderate, and even moisture keeps scallions crisp and mild. Water lightly but regularly, especially while seed is germinating — a dry seed bed in tropical sun can kill a sowing in a day. Morning watering is best, and a light mulch helps the shallow roots stay cool and damp. Use the watering calculator to work out how much water your bed needs.
Companion plants
Good companions for scallions 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 aphids, slugs and cutworms. Slugs nibble young seedlings on damp nights, so check after rain and keep the bed clear of debris. Aphids can be washed off with water. Because scallions grow fast and are harvested young, serious pest problems are uncommon if you sow in the cool season and harvest on time.
Harvest and storage
Harvest scallions when the stems are pencil-thick, about two months after sowing, by pulling the whole plant or cutting the green tops about an inch above the soil and letting them regrow. Pick in the morning when they are crisp, wash them well, and use them fresh — scallions lose their snap quickly in tropical heat, so pick only what you need for the next day or two.
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 scallions does not follow another Amaryllidaceae 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: Leeks in Zone 13 and the same crop in a cooler zone, Scallions in Zone 11. The December 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 scallions in Zone 13?
Sow scallions 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.
How often should I sow scallions in Zone 13?
Every two weeks through the cool season. Each sowing takes about two months, so a fortnightly rhythm gives you a continuous supply and spreads the risk if one batch bolts or is hit by pests.
Can I regrow scallions from shop-bought ones?
Yes — stand the white root ends in water or plant them straight into moist soil and they will sprout new green tops within days. It is a handy shortcut, but seed-grown plants are sturdier and cheaper in quantity, so use regrowth as a top-up rather than your main crop.
What soil and spacing do scallions need?
It needs full sun, soil pH 6.0–7.0, and spacing of 2–3 inches between plants. Work compost into the bed before planting and test the soil rather than guessing the pH.