SproutSmart
SproutSmart™ Intelligent Garden Sowing

Cosmos Sensation

Zone 6b Save Garden

Planting Schedule

Add Cosmos Sensation to your garden to build a schedule and get reminders.

Feathery, cloudlike blooms in a riot of warm pinks, rosy reds, and crisp whites open to a silky, petal-soft presence that feels almost luminous in the garden.

Cosmos Sensation carries a lively, upright branching habit and produces abundant flowers with a delicate, airy texture—ideal for long-lasting color and fresh bouquets. Grow it for a breezy summer spectacle that keeps flowering as the days lengthen, turning beds and borders into a painterly swirl of motion.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Cosmos Sensation

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

MilestoneDate
Start IndoorsDirect Sow
Last FrostApr 25th
Transplant / Sow OutdoorsApr 25th
Harvest BeginsJun 24th
Harvest EndsOct 16th

Crop Details

TraitValue
Days to Maturity60
Sun RequirementsFull SunFull sun
Growth HabitUpright
Support NeededNone
Planting DepthSurface
Germination Temp (°F)70
Min Soil Temp (°F)55
Min Night Temp (°F)50
Harden Off (days)7

Frequently Asked Questions

How do I prevent and treat powdery mildew on Cosmos (Cosmos bipinnatus) like 'Sensation'?
Powdery mildew shows up as a white, talc-like coating on leaves and spreads quickly in warm, still air. Start by thinning so plants have airflow, water at the base (not over the foliage), and remove the most affected leaves early. If it keeps spreading, spray a labeled potassium bicarbonate or horticultural sulfur product per the label directions, avoiding application during very hot afternoons.
How often should I water Cosmos (Cosmos bipinnatus) during the main growing phase (after seedlings establish)?
After establishment, keep the soil evenly moist but not soggy—water when the top 1–2 in (2–5 cm) of soil feels dry. During active flowering, this usually means deep watering about 1–2 times per week depending on heat and soil, with more frequent watering in sandy beds. Cosmos tolerates some dryness, but long dry spells can reduce flower production, so aim for consistent moisture during bloom.
When are Cosmos (Cosmos bipinnatus) 'Sensation' ready to harvest for cut flowers?
Harvest when the ray petals are fully expanded and the center disk looks developed but not dried and brown—this is typically around 60 days from sowing/early germination depending on conditions. Cut in the morning, and re-cut stems just above a leaf node to encourage branching and additional blooms. Expect the most productive flush when you harvest regularly, before flowers begin setting seed.

Today's Conditions

Outdoor planting for Cosmos Sensation in Zone 6b typically begins around 2026-04-25. Wait until soil reaches at least 55°F before transplanting Cosmos Sensation.

Garden Alerts

In Zone 6b, the average last spring frost is around April 25. Watch soil temperature before transplanting Cosmos Sensation.

Today's Conditions

Outdoor planting for Cosmos Sensation in Zone 6b typically begins around 2026-04-25. Wait until soil reaches at least 55°F before transplanting Cosmos Sensation.

Garden Alerts

In Zone 6b, the average last spring frost is around April 25. Watch soil temperature before transplanting Cosmos Sensation.

Sowing Tips

Transplant Conditions

Wait until soil reaches 55°F and nights stay above 50°F before moving outdoors. Harden off for 7 days first.

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 Cosmos, it’s usually best to direct-sow after frost or use a very shallow sow indoors and transplant only when nights are reliably warm to avoid stunting.