🌸 When to Plant Zinnias in Zone 12

Zone 12 is frost-free (Hawaiʻi lowlands, Puerto Rico) — plant zinnias nearly year-round, avoiding peak summer heat.

No frost windows apply in zone 12. Plant zinnias in late winter for a pre-summer harvest and again in late summer — peak heat is the season to avoid, not frost.
Zone 12 frost window
Frost-free
Hawaiʻi lowlands, Puerto Rico
Spacing
10″ / 18″
plants / rows
Maturity
60–70 days
from sowing

Growing zinnias in zone 12

The more you cut, the more they bloom — harvest stems deep and plants branch furiously. Water at the base, not overhead, to keep powdery mildew off late-summer foliage.

Zone 12 covers hawaiʻi lowlands, Puerto Rico — tropical — timing follows wet and dry seasons rather than frost.

Make it local

These windows use zone 12's typical frost dates. For windows computed from your frost dates, run the ZIP code frost lookup and open the planting calendar — it remembers your city. The seed starting scheduler turns the whole seed rack into one printable, date-sorted list.

Frequently asked questions

When should I plant zinnias in zone 12?

Zone 12 is frost-free, so timing flips from frost-avoidance to heat management: plant zinnias nearly year-round, avoiding peak summer heat. Late winter and late summer plantings avoid fruiting during the hottest stretch.

Does zinnias grow well in zone 12?

Yes — heat-loving crops like zinnias thrive in zone 12, often across a far longer window than mainland gardens get. Watch water needs and intense midsummer sun.