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Sea Shells Mix

Family: Asteraceae Annual flowering plant
Zone 6b Save Garden

Planting Schedule

Add Sea Shells Mix to your garden to build a schedule and get reminders.

Feathery, seashell-swirled blooms rise like confetti on airy stems, opening into luminous, daisy-like faces that shimmer in the sun.

The petals are satisfyingly crisp and lightly ruffled, holding their shape with a graceful, wind-kissed texture—ideal for bouquets that look fresh and abundant from the first day. Sea Shells Mix is a pollinator favorite with a vivid, mixed palette, perfect for gardeners who want a long season of color and movement in the flower bed.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Sea Shells Mix

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 DepthNormal
Germination Temp (°F)75
Min Soil Temp (°F)55
Min Night Temp (°F)45
Harden Off (days)Not Required

Frequently Asked Questions

What pest or disease is most likely on Cosmos bipinnatus, and how do I control it?
Cosmos bipinnatus commonly suffers from powdery mildew (white, dusty growth) and occasional aphid outbreaks, especially in warm, humid weather or crowded plantings. Improve airflow by spacing plants and watering at soil level; remove heavily infected leaves early. For aphids, spray plants with a strong jet of water or treat with insecticidal soap, and avoid nitrogen-heavy feeding that can trigger soft, aphid-friendly growth.
How often should I water Cosmos bipinnatus during the main growing phase?
During active growth, water deeply when the top 1 inch of soil feels dry, then let excess water drain—cosmos dislikes staying soggy. Aim for roughly 1 inch of water per week total (from rainfall plus irrigation) during typical conditions, increasing slightly during hot spells and reducing in cool, wet weather. Consistent moisture supports steady flowering, but overwatering encourages mildew.
How can I tell when Cosmos bipinnatus is ready to harvest?
Harvest for cut flowers when the blooms are fully open and the petals are crisp, not limp; new buds should continue forming for about 60 days after sowing. If harvesting for seed, let the flower heads dry on the plant until the seeds are brown and firm, then cut and finish drying indoors before storing. Deadheading spent flowers regularly will keep cosmos flowering longer.

Today's Conditions

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

Garden Alerts

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

Today's Conditions

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

Garden Alerts

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

Sowing Tips

Transplant Conditions

Wait until soil reaches 55°F and nights stay above 45°F before moving outdoors.

Expert Note

For best cosmos stems for bouquets, sow after frost and keep seedlings lightly thinned for airy growth and long straight stems.