SproutSmart
SproutSmart™ Intelligent Garden Sowing

Sensation Purity

Cosmos
Zone 11b Save Garden

Planting Schedule

Add Sensation Purity to your garden to build a schedule and get reminders.
Botanical illustration of Sensation Purity
70d to harvest

Feathery, airy blooms arrive in a steady crescendo, painting the garden with a luminous clarity that feels almost weightless in the breeze. Sensation Purity’s petals hold their color with a clean, crisp presence—silky to the eye, light-catching at every angle—making it a standout for long-lasting floral display. Grow it for a pollinator-forward border that brings continuous color from early summer into fall, with flowers that look as fresh as they feel.

Crop Dates

Growing note: In frost-free Zone 11b, grow this cool-season crop during the cooler dry season (October–February).
MilestoneDate
Start Indoors—
ClimateFrost-Free Climate
Transplant / Sow OutdoorsOct 1st
Harvest BeginsDec 10th
Harvest EndsFeb 28th

Crop Details

TraitValue
Days to Maturity70
Sun RequirementsFull SunFull sun
Growth HabitUpright
Support NeededNone
Planting DepthNormal
Germination Temp (°F)70
Min Soil Temp (°F)50
Min Night Temp (°F)40
Harden Off (days)7

Today's Conditions

Outdoor planting for Sensation Purity in Zone 11b typically begins around 2026-10-01. Wait until soil reaches at least 50°F before transplanting Sensation Purity.

Garden Alerts

In frost-free Zone 11b, grow this cool-season crop during the cooler dry season (October–February).

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Frequently Asked Questions

What pest or disease is most likely on Cosmos bipinnatus (Cosmos) and how do I treat it?
Watch for powdery mildew, especially when plants are crowded and nights are cool and humid. Improve airflow by thinning to about 8–12 in (20–30 cm) between plants, then spray with a labeled horticultural sulfur product as soon as white mildew patches appear. If you spot heavy leaf damage, remove affected leaves to reduce spread rather than waiting for it to “burn off.”
How often should I water Cosmos bipinnatus during the main growing phase?
During active growth and before peak flowering, keep the soil evenly moist but not soggy—water when the top 1 in (2–3 cm) dries. Expect roughly 1–2 times per week in typical warm weather, with deeper watering that wets the root zone, since Cosmos is drought-tolerant once established. In containers, check more frequently and don’t let them dry out completely between waterings.
Botanical illustration of Sensation Purity

Feathery, airy blooms arrive in a steady crescendo, painting the garden with a luminous clarity that feels almost weightless in the breeze. Sensation Purity’s petals hold their color with a clean, crisp presence—silky to the eye, light-catching at every angle—making it a standout for long-lasting floral display. Grow it for a pollinator-forward border that brings continuous color from early summer into fall, with flowers that look as fresh as they feel.

Today's Conditions

Outdoor planting for Sensation Purity in Zone 11b typically begins around 2026-10-01. Wait until soil reaches at least 50°F before transplanting Sensation Purity.

Garden Alerts

In frost-free Zone 11b, 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 50°F for reliable germination and early growth.

Direct Sow Preferred

Sensitive roots — does not transplant well. If starting indoors, use biodegradable pots and disturb roots as little as possible when moving outdoors.

Expert Note

For best pure-looking blooms, grow in full sun with light-to-moderate feeding (too much nitrogen makes tall, leafy plants with fewer flowers).