🌸 Nasturtium

Sowing window (UK)	April to May
Minimum soil temperature	10°C at seed depth
Sowing depth	2 cm
Spacing	30 cm apart
Days to germination	10 days
Days to harvest	60 days
Sowing method	Direct sow outdoors
Frost hardy	No
Sun	full-sun
Watering	low
Plant family	Tropaeolaceae

When should I sow Nasturtium in the UK?

In the UK, sow Nasturtium from April to May. It is normally sown direct outdoors. Wait until the soil has reached 10°C at seed depth rather than going by the calendar - nasturtium will sit and rot in cold ground.

What soil temperature does Nasturtium need to germinate?

Nasturtium needs a minimum soil temperature of 10°C at seed depth to germinate reliably. Below that, germination is slow and patchy, and seed is more likely to rot than sprout. Measure at around 5cm down, in the morning, rather than trusting air temperature.

How deep and how far apart should I sow Nasturtium?

For Nasturtium, sow it 2cm deep and space plants 30cm apart.

How long does Nasturtium take to grow?

Nasturtium takes roughly 60 days from sowing to harvest. Seed usually germinates in about 10 days.

Is Nasturtium frost hardy?

No. Nasturtium is not frost hardy. Do not put it outside until the risk of frost has passed in your area, and be ready to fleece it if a late frost is forecast.

Sowing data cross-checked against RHS growing guides and UK seed-merchant catalogues. Soil temperatures are the minimum for reliable germination, measured at seed depth.