SproutSmart
SproutSmart™ Intelligent Garden Sowing

Imperial

Broccoli
Zone 13b Save Garden

Planting Schedule

Add Imperial to your garden to build a schedule and get reminders.
Botanical illustration of Imperial
68d to harvest

Velvety, deep-blue green curds form a tight, regal dome on sturdy stems—lush to the eye and richly flavored in the garden. Imperial delivers a dense, fine-textured head with a pleasing snap, plus dependable side shoots for extended harvest. Ideal for roasting, steaming, and turning into creamy sauces, this is a standout broccoli for gardeners who want bold color and consistently satisfying texture from one planting.

Crop Dates

Growing note: In frost-free Zone 13b, grow this cool-season crop during the cooler dry season (October–February).
MilestoneDate
Start Indoors—
ClimateFrost-Free Climate
Transplant / Sow OutdoorsOct 1st
Harvest BeginsDec 8th
Harvest EndsFeb 28th

Crop Details

TraitValue
Days to Maturity68
Sun RequirementsFull SunFull sun
Growth HabitRosette
Support NeededNone
Planting DepthNormal
Germination Temp (°F)45
Min Soil Temp (°F)40
Min Night Temp (°F)32
Harden Off (days)6

Today's Conditions

Outdoor planting for Imperial in Zone 13b typically begins around 2026-10-01. Wait until soil reaches at least 40°F before transplanting Imperial.

Garden Alerts

In frost-free Zone 13b, grow this cool-season crop during the cooler dry season (October–February).

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Frequently Asked Questions

How often should I water during the main growing phase for Brassica oleracea var. italica, and what soil moisture level should I keep?
During head (curd) formation, keep soil consistently evenly moist—aim for the top 1 inch to stay damp, not soggy. Water deeply about 2–3 times per week depending on heat and rainfall, and reduce frequency only if the soil is staying wet longer than a day. Uneven watering can lead to loose, stressed curds and increased susceptibility to diseases.
How can I tell when Brassica oleracea var. italica (“imperial”) is ready to harvest?
Harvest when the curd is firm and tightly budded, with the individual florets still compact—before the surface starts to separate and yellow. Typical timing is around 68 days from transplanting/seedling establishment; in practice, harvest at the first clear window of tightness rather than waiting for size alone. Cut the main head with 6–8 in (15–20 cm) of stem, and keep an eye out for smaller side shoots that can be harvested after the main cut.
Botanical illustration of Imperial

Velvety, deep-blue green curds form a tight, regal dome on sturdy stems—lush to the eye and richly flavored in the garden. Imperial delivers a dense, fine-textured head with a pleasing snap, plus dependable side shoots for extended harvest. Ideal for roasting, steaming, and turning into creamy sauces, this is a standout broccoli for gardeners who want bold color and consistently satisfying texture from one planting.

Today's Conditions

Outdoor planting for Imperial in Zone 13b typically begins around 2026-10-01. Wait until soil reaches at least 40°F before transplanting Imperial.

Garden Alerts

In frost-free Zone 13b, grow this cool-season crop during the cooler dry season (October–February).

Sowing Tips

Soil Temperature

Direct sow or transplant when soil at planting depth holds 40°F for reliable germination and early growth.

Expert Note

For the tightest heads, keep temperatures consistently cool early (avoid letting seedlings sit in warm soil) and water evenly to prevent stress-driven loose heads.