When to plant Watercress in Cambridge

Nasturtium officinale

A hardy perennial leafy vegetable for containers of compost kept constantly wet with clean water. It grows best in cool conditions and light shade. Keep home-grown edible watercress separate from natural ponds and streams where water may be contaminated by livestock or wildlife.

20 cm · Partial Shade · High Water

Add to garden

Calibrated to Cambridge · last frost ≈ 7 May

Sow indoors April to May, plant out May to July, harvest May to December. Frost risk October to May.
Activity	January	February	March	April	May	June	July	August	September	October	November	December
Sow indoors	No	No	No	Yes	Yes	No	No	No	No	No	No	No
Plant out	No	No	No	No	Yes	Yes	Yes	No	No	No	No	No
Harvest	No	No	No	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Growing guide

What to do through the growing season

01
Sow Seeds
2 Apr to 14 May Optional · repeat every 3 weeks
Sow seeds around 2nd April - 14th May on the surface of moist compost in small pots or modules, then press them in lightly rather than burying them. Keep the compost constantly damp while they germinate, and sow a fresh batch every 21 days for a steady supply.
02
Thin Seedlings
30 Apr to 18 Jun Dates as each sowing reaches this stage
When seedlings are large enough to handle, from 30th April, thin them so the strongest plants have room to spread. Keep the soil wet at all times, because even brief drying checks growth.
03
Transplant
7 May to 9 Jul
Move seedlings to their final container around 7th May - 9th July, spacing them apart in wet compost standing in shallow clean water. Water in thoroughly, keep the compost constantly wet, and refresh the standing water regularly. Do not use untreated water from streams or livestock ponds for edible leaves.
04
Feed Plants
7 May to 19 Oct Dates as each sowing reaches this stage Optional · repeat every 2 weeks
From 7th May, give a very light liquid feed every 14 days only if growth slows. Avoid strong feeding that makes leaves coarse, remove weeds promptly, and keep the container topped up with clean water.
05
Harvest Leaves
21 May to 24 Dec Dates as each sowing reaches this stage
Start cutting from 21st May when plants are well rooted and the shoots are leafy. Pick little and often through to 24th December, taking the outer stems first and leaving the centre to regrow.