Cosmos · Arequipa, Arequipa, Peru
When to sow cosmos in Arequipa
Main outdoor window
26 Aug - 9 Sep
The window this page is built around.
Timed from last spring frost
19 August
In Arequipa, on your chosen risk.
Ready to pick
4-24 Nov
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Arequipa
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Start indoors
22 Jul - 5 Aug
Four weeks before your last frost, under cover or on a windowsill.
Sow direct
26 Aug - 9 Sep
One week after your last frost.
Plant out
26 Aug - 9 Sep
One week after your last frost.
In flower
4-24 Nov
Cosmos through the year
Against the frost risk in Arequipa
Why these dates
Sow direct around the last frost date. Pinch young plants once to produce a bushier, more productive plant.
Frost-tender at both ends, but flowers freely until the first autumn frost stops it outright.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Cosmos are timed from 4 weeks before that frost for an indoor start, with planting out 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Arequipa.
The median frost-free season here is 288 days, against 70 to 90 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Arequipa
Other flowers to time
Growing cosmos in Arequipa
When should I plant cosmos in Arequipa?
Aim for 26 Aug - 9 Sep in an average year. If you would rather not gamble on the weather, wait until 16-30 Sep - by then frost has finished in nine years out of ten.
When will cosmos be ready to harvest in Arequipa?
Expect to start picking around 4-24 Nov, based on 70 to 90 days to maturity from the planting date calculated for this location.
How much frost will cosmos tolerate?
Frost-tender at both ends, but flowers freely until the first autumn frost stops it outright.