Cut-Flower Succession Sowing Planner
A single sowing of cut flowers gives a flush of blooms, then quality and stem length fall away. Succession sowing, a new batch every few weeks, keeps fresh, long stems coming all season.
Runs in your browser. Nothing you enter is stored.
What this planner does
Choose the date you want the first flowers and how long the variety takes from seed to bloom. The planner counts back to each sowing date, shows when every batch flowers and warns you if gaps would appear between batches.
How to use the cut-flower succession sowing planner
- Optional: pick a flower to fill in typical days to bloom and flowering period.
- Choose the date you want the first stems.
- Enter the days from sowing to first flowers for your variety (from the seed packet) and how many weeks you want flowers.
- Set the gap between sowings and how long one batch keeps producing.
- Copy or print the sowing calendar and add the dates to your diary.
How the calculation works
batches = ceil(weeks of flowers ÷ sowing interval) first flowers of batch n = first bloom date + (n − 1) × interval sow date of batch n = first flowers of batch n − days to bloom batch n flowers until = first flowers + flowering weeks
Each batch is timed backwards from the day you want it in flower. If one batch stops flowering before the next begins, the planner warns you to sow more often.
Worked example
Zinnias that take 75 days to flower, wanted from 1 July for 15 weeks with a sowing every 3 weeks, need 5 sowings: 17 April, 8 May, 29 May, 19 June and 10 July. The batches start flowering on 1 July, 22 July, 12 August, 2 September and 23 September.
Assumptions and limitations
- Days to bloom depend on temperature and day length; early-season sowings often take longer than late ones.
- The planner does not know your frost dates or hemisphere. Check that sowing dates fall in a safe window for direct sowing or transplanting where you live.
- Late batches may be cut short by the first autumn frost or by shortening days.
Frequently asked questions
How often should I succession sow zinnias?
Every 2–4 weeks from your first safe sowing date until about 10–12 weeks before your first autumn frost is a common approach.
Which flowers need succession sowing?
Single-stem flowers such as sunflowers need sowing every 1–2 weeks. Cut-and-come-again flowers like zinnias and cosmos need fewer batches, but later sowings give longer, cleaner stems.
How do I find days to bloom?
Seed packets and catalogues usually list days to maturity or days to flower. Add a week or two for cooler conditions or for transplants that need to settle in.
Does this work in the Southern Hemisphere?
Yes. The planner only counts days between dates, so it works anywhere. Just choose first bloom dates that suit your own season.