Nasturtium · Pretoria, Gauteng, South Africa
When to sow nasturtiums in Pretoria
Main outdoor window
31 Jul - 14 Aug
The window this page is built around.
Timed from last spring frost
24 July
In Pretoria, on your chosen risk.
Ready to pick
19 Sep - 4 Oct
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 Pretoria
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.
Sow direct
31 Jul - 14 Aug
One week after your last frost.
In flower
19 Sep - 4 Oct
Nasturtiums through the year
Against the frost risk in Pretoria
Why these dates
Direct sow after last frost. The large seed germinates readily and transplanting is unnecessary.
Frost-tender throughout. Often the first plant in the garden to signal that a frost occurred overnight.
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. Nasturtiums are timed for direct sowing 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Pretoria.
The median frost-free season here is 322 days, against 50 to 65 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Pretoria
Other flowers to time
Growing nasturtiums in Pretoria
When should I plant nasturtiums in Pretoria?
Aim for 31 Jul - 14 Aug in an average year. If you would rather not gamble on the weather, wait until 17-31 Aug - by then frost has finished in nine years out of ten.
When will nasturtiums be ready to harvest in Pretoria?
Expect to start picking around 19 Sep - 4 Oct, based on 50 to 65 days to maturity from the planting date calculated for this location.
How much frost will nasturtiums tolerate?
Frost-tender throughout. Often the first plant in the garden to signal that a frost occurred overnight.