Dianthus (China Pink & Sweet William): Timing, Spacing, Care & Bloom
Quick answer
China pink: start indoors about 8 weeks before last frost (Purdue). Sweet William: start 6–8 weeks before last frost (MSU/UAEX/Purdue); fall sow 6–8 weeks before first frost (UAEX).
Dianthus (China pink & Sweet William) at a glance
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated
Dianthus hub: china pink is Dianthus chinensis; Sweet William is D. barbatus. Neither is carnation (D. caryophyllus).
Safety: NC State poison severity Low for china pink — skin irritation. (NC Dianthus chinensis)

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.
China pink planting timing
Purdue HO-14: Dianthus — start indoors 8 weeks before last frost; frost tolerance after hardening medium. (Purdue HO-14-W) NC: grown primarily as annuals; full sun, afternoon shade in warm climates. (NC china pink) WSU “8–10 weeks sowing to transplant”.
Sweet William
Sweet William (Dianthus barbatus) is a related biennial/short-lived perennial — not china pink and not carnation. MSU: sow seeds 6–8 weeks before the last frost; harden and transplant 6–8 weeks after sowing. (MSU Sweet William) UAEX: indoors 6–8 weeks before the last frost, or sow 6–8 weeks before the first frost. (UAEX dianthus) Purdue Dianthus table supports ~8 weeks before last frost.
Depth and spacing
PSU: china pinks about 6–8 inches. (PSU sowing annual seeds)
Sun, soil and water
Full sun; well-drained soil. Afternoon shade in hot humid summers (NC).
Care and bloom
Deadhead for rebloom. Sweet William often blooms year two if biennial types.
Pests and diseases
Drainage first; avoid wet crowns.
Related: ZIP planner · planting calendars · garden phlox
Frequently asked questions
When do I start china pink?
About 8 weeks before last frost (Purdue).
Sweet William timing?
6–8 weeks before last frost indoors (MSU/UAEX); fall sow 6–8 weeks before first frost (UAEX).
Carnation?
No — different Dianthus species.
Sources
- NC State Extension: NC Dianthus chinensis
- Purdue University: Purdue HO-14-W
- Mississippi State University Extension: MSU Sweet William
- University of Arkansas Cooperative Extension: UAEX dianthus
- Penn State Extension: PSU sowing annual seeds