Marigold · Brussels, Brussels Capital, Belgium
When to sow marigolds in Brussels
Main outdoor window
20 Apr - 4 May
The window this page is built around.
Timed from last spring frost
13 April
In Brussels, on your chosen risk.
Ready to pick
9-29 Jun
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 Brussels
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
2-16 Mar
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
20 Apr - 4 May
One week after your last frost.
Plant out
20 Apr - 4 May
One week after your last frost.
In flower
9-29 Jun
Marigolds through the year
Against the frost risk in Brussels
Why these dates
Six weeks indoors produces flowering plants at transplant time. Direct sowing works but flowers three weeks later.
Killed by frost at both ends of the season, with no tolerance at any growth stage.
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. Marigolds are timed from 6 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 Brussels.
The median frost-free season here is 216 days, against 50 to 70 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Brussels
Other flowers to time
Growing marigolds in Brussels
When should I plant marigolds in Brussels?
Aim for 20 Apr - 4 May in an average year. If you would rather not gamble on the weather, wait until 30 Apr - 14 May - by then frost has finished in nine years out of ten.
When will marigolds be ready to harvest in Brussels?
Expect to start picking around 9-29 Jun, based on 50 to 70 days to maturity from the planting date calculated for this location.
How much frost will marigolds tolerate?
Killed by frost at both ends of the season, with no tolerance at any growth stage.