How to grow Watercress

Nasturtium officinale

A fast-growing aquatic perennial with peppery leaves. It likes cool, wet conditions, gives a first cut 4–6 weeks after sowing and regrows to be cut again.

Quick facts

Type	Vegetable
Family	Brassicaceae
Light	Full sun
Soil pH	6.5–7.5
Frost	tolerates light frost
Soil for sowing	from 10 °C
Germination	7 days
Sowing to harvest	40 days
Where it grows	Greenhouse, Open ground, At home

When to plant

It tolerates light frost: sow straight into the bed about three weeks before your last spring frost.

In an unheated greenhouse everything moves about three weeks earlier.

The first harvest comes about 40 days after the shoots appear.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	10…18 °C	—
Growth	every 3 days	10…20 °C	balanced (NPK), at the start of the stage
Harvest	every 3 days	10…20 °C	balanced (NPK), at the start of the stage

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	8…18 °C	—
Growth	every 3 days	8…20 °C	balanced (NPK), at the start of the stage
Harvest	every 3 days	8…20 °C	balanced (NPK), at the start of the stage

At home

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	15…22 °C	—
Growth	every 3 days	15…24 °C	balanced (NPK), at the start of the stage
Harvest	every 3 days	15…24 °C	balanced (NPK), at the start of the stage

Growing notes

Light

Full sun or partial shade, as long as the roots stay wet.

Soil

Rich, constantly wet soil, or a pot standing in water; pH 6.5–7.5 is best, but it tolerates a wide range.

Care

Sow on the surface or barely cover the seed and keep it wet. Stand pots in 5–8 cm of water and change the water once or twice a week. It needs little feeding; a complete soluble fertiliser added to the water at the label rate prevents deficiencies. Cut the stems about 4 cm above the base so they regrow, and pick before it flowers, as the flavour fades after flowering and in heat above 29 °C.

Pests and diseases of Watercress

Sources

Figures checked against these sources.