Watercress Microgreen Seeds

Watercress is a fine-seeded specialty microgreen with tender green foliage and a fresh peppery flavour. It requires no pre-soaking and benefits from consistent moisture throughout establishment.

What You Need

• Watercress Microgreen Seeds
• A shallow tray with drainage holes
• A solid lower tray for bottom watering
• Fine seed-raising mix, coco coir or another suitable fine growing medium
• Clean drinking-quality water
• Fine mist sprayer
• A second tray or suitable germination cover
• Bright natural light or suitable grow lights
• Clean scissors or a sharp harvesting knife

Seed Rate

For a standard 25 × 50cm microgreen tray, use approximately:

2–3g dry seed per tray

Watercress seed is exceptionally fine, with several thousand seeds per gram.

Spread the seed thinly and evenly and avoid concentrated patches.

Pre-Soak

No pre-soaking required.

Sow Watercress seed dry.

True Watercress seed is not mucilaginous, so it does not form the thick gelatinous coating associated with crops such as basil or garden cress.

Step-by-Step Instructions

1. Clean and thoroughly rinse trays, covers and growing tools.
2. Add approximately 2–3cm of fine seed-raising mix, coco coir or another suitable growing medium.
3. Moisten the medium thoroughly and allow excess water to drain.
4. Spread approximately 2–3g of dry seed evenly across the surface.
5. Gently press the seed into contact with the moist medium.
6. Keep the seed at or very close to the surface. Do not bury deeply.
7. Mist gently using clean drinking-quality water.
8. Cover briefly during early establishment.
9. Check the tray daily and maintain consistent surface moisture.
10. Remove the cover once germination is established.
11. Provide bright indirect natural light or suitable grow lights.
12. Maintain good airflow.
13. Bottom water once roots are established.
14. Continue growing until the desired cotyledon or early true-leaf stage.

Covered Establishment

Use approximately:

3–5 days

of covered establishment as a starting point.

Heavy weighting is unnecessary.

Remove the cover once seedlings are germinating and establishing rather than keeping successfully emerged Watercress in prolonged darkness.

For more information, see Microgreen Blackout Explained.

Germination

Expect germination in approximately:

5–10 days

Some emergence may occur earlier, while cooler conditions can extend germination.

Watercress seed is extremely small, so steady surface moisture is particularly important.

Temperature

Aim for approximately:

16–20°C

Watercress naturally favours cool to moderate conditions.

Avoid excessive heat and stagnant humidity.

Light & True-Leaf Development

Once uncovered, provide bright indirect natural light or suitable grow lights.

The crop begins with small green cotyledons before developing increasingly recognisable rounded Watercress leaves.

Allowing the first true leaves to begin developing provides:

• a more characteristic Watercress appearance;
• a more substantial culinary crop; and
• stronger peppery flavour.

Watering

Watercress prefers consistent moisture, but a microgreen tray should still have good drainage.

During germination:

• keep the surface evenly moist;
• mist gently when required;
• avoid flooding the fine seed; and
• do not allow repeated drying.

Once roots establish, bottom watering is preferable.

For detailed guidance, see How to Water Microgreens: Misting vs Bottom Watering.

Keep the medium consistently moist without allowing stagnant water to remain beneath the tray for extended periods.

Harvest & Storage

For a developed microgreen crop, harvest approximately:

14–21 days from sowing

Watercress may be harvested earlier at the cotyledon stage. Use crop development rather than the calendar alone as the final guide.

A developed crop is generally ready when:

• foliage is fresh and green;
• cotyledons are fully open;
• early rounded true leaves are beginning to develop;
• shoots are approximately 4–7cm tall;
• stems remain tender; and
• the characteristic peppery flavour is evident.

Cut cleanly just above the growing medium using clean scissors or a sharp harvesting knife.

For more information, see How to Harvest & Store Microgreens.

Refrigerate promptly in a clean container. If washed before refrigeration, drain and dry thoroughly first.

Watercress vs Garden Cress

True Watercress is Nasturtium officinale.

It should not be confused with Garden Cress, which is Lepidium sativum.

Watercress:

• has very fine, non-mucilaginous seed;
• prefers consistently moist conditions;
• develops rounded green foliage;
• has a fresh peppery flavour; and
• generally grows more slowly when taken to the true-leaf stage.

Use growing instructions written specifically for Watercress rather than assuming all crops sold as “cress” behave the same way.

Growing as Baby Leaf

For baby-leaf production:

1. Sow considerably less densely than for microgreens.
2. Allow individual plants more room.
3. Maintain consistent moisture.
4. Provide good light.
5. Continue growing through several true leaves.
6. Harvest tender shoots progressively.

Growing Watercress to Maturity

Watercress is a perennial aquatic or semi-aquatic culinary plant.

For mature growing:

1. Surface sow or cover the seed only very lightly.
2. Maintain consistent moisture throughout germination.
3. Grow established plants in very moist soil, self-watering containers or an appropriate controlled water-growing system.
4. Provide full sun to partial shade.
5. Maintain a clean water source.
6. Harvest young leafy shoots progressively.

Mature Watercress can tolerate a continually wet root zone once established, but this should not be confused with leaving an indoor microgreen tray stagnant and waterlogged.

For dedicated mature growing, see Watercress Herb Seeds.

Root Hairs vs Mould

Fine white root hairs can occasionally be mistaken for mould.

Root hairs generally:

• grow directly from individual roots;
• appear relatively evenly; and
• become less noticeable immediately after watering.

Mould is more likely to:

• spread irregularly between seedlings;
• form web-like growth;
• persist after watering; or
• occur alongside slime, discolouration or unpleasant smells.

If you are uncertain, see Mould vs Root Hairs on Sprouts & Microgreens.

Discard crops showing obvious spoilage.

Clean Growing / Food Safety

Use clean trays, fresh growing medium, drinking-quality water and clean harvesting equipment.

Watercress has a natural association with aquatic environments, but indoor microgreen production should use clean drinking-quality water, not untreated creek, pond or stream water.

Maintain good drainage and airflow and discard crops showing mould, slime, decay, abnormal discolouration or unpleasant smells.

Seed Storage

Store unused Watercress seed sealed in a cool, dry and dark place away from heat, moisture and direct sunlight.

For longer-term storage, refrigeration can help maintain viability. Keep refrigerated seed sealed while it returns to room temperature before opening to reduce condensation.