Watercresses in Penisa'r Waun

Nasturtium officinale

Watercress
Watercress · Nasturtium officinale

Watercress is a hardy perennial leafy crop that grows best in shallow running water or very wet soil. In the UK it’s usually grown outdoors in a pond basket, streamside bed, or container kept constantly wet, and it gives the best leaves in cool weather.

20 cm · Partial Shade · High Water

Add to garden

Calibrated to Penisa'r Waun · last frost ≈ 18 Apr

Sow February to May, plant out April to May, harvest May to November. Frost risk November to April.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
SowNoYesYesYesYesNoNoNoNoNoNoNo
Plant outNoNoNoYesYesNoNoNoNoNoNoNo
HarvestNoNoNoNoYesYesYesYesYesYesYesNo

Growing guide

Step-by-step instructions for growing Watercress

  1. 01

    Sow Seeds

    16 Feb to 19 May every 3 weeks

    Sow seeds around 16th February - 19th May on the surface of very moist compost, 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.

  2. 02

    Thin Seedlings

    17 Apr to 24 Apr

    When seedlings are large enough to handle, from 17th April, thin them so the strongest plants have room to spread. Keep the soil wet at all times, because even brief drying checks growth.

  3. 03

    Transplant

    4 Apr to 16 May

    Move seedlings to their final spot around 4th April - 16th May, spacing them well apart in mud-like soil or a shallow run of water. Water in thoroughly straight after planting and keep the roots submerged or constantly wet.

  4. 04

    Feed Plants

    25 Apr to 12 Nov every 2 weeks

    From 25th April, give a very light liquid feed every 14 days if growth slows, but avoid strong feeding that makes the leaves coarse. Keep the bed weed-free and topped up with water.

  5. 05

    Harvest Leaves

    22 May to 12 Nov

    Start cutting from 22nd May when plants are well rooted and the shoots are leafy. Pick little and often through to 12th November, taking the outer stems first and leaving the centre to regrow.

Companion plants

Tap a plant to see why it works (or doesn't) with Watercress.

Good companions

Plants to avoid

Why companion planting matters

Companion planting can deter pests, improve pollination, and make better use of space. Some plants confuse pests or attract beneficial insects; others improve soil or offer shade to neighbours that need it.

Watercress guides by town

See how Watercress timing shifts in other towns with different frost dates.