Celery Microgreen Seeds

Celery is a slow-growing specialty microgreen with exceptionally fine seed. Unlike many common microgreens, celery should remain near the surface and receive light during germination rather than being placed under a prolonged opaque blackout cover.

If you are new to specialty crops, the OzSprout How to Grow Microgreens at Home guide explains the general tray-growing process.

What You Need

• Celery Microgreen Seeds – Tall Utah
• A shallow microgreen tray with drainage holes
• A solid lower tray for bottom watering
• Fine seed-raising mix, coco coir or another fine microgreen growing medium
• Clean drinking-quality water
• Fine mist sprayer
• Optional clear humidity dome or transparent cover
• Bright natural light or suitable grow lights
• Clean scissors or a sharp harvesting knife

Seed Rate

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

3–5g dry seed per tray

Celery seed is extremely small, with approximately 2,000–3,000 seeds per gram.

Spread it as evenly as possible across the surface and avoid thick patches. A few grams already provide a very high number of seedlings.

Pre-Soak

No pre-soaking required.

Celery seed is easier to distribute evenly when sown dry.

Step-by-Step Instructions

1. Clean your equipment. Wash and thoroughly rinse the growing tray, lower tray, humidity cover and tools.
2. Prepare the growing medium. Add approximately 2–3cm of fine seed-raising mix, coco coir or another suitable fine growing medium.
3. Moisten thoroughly before sowing. Water evenly and allow excess water to drain. The surface should be consistently damp but not saturated.
4. Measure the seed. Use approximately 3–5g of dry seed for a 25 × 50cm tray.
5. Surface sow. Sprinkle the seed evenly across the growing surface.
6. Press gently. Lightly press the seed into contact with the moist medium. Do not bury deeply.
7. Mist carefully. Use a fine spray to moisten the seed without washing it into clusters.
8. Provide light during germination. Place the tray in bright indirect natural light or beneath suitable grow lights.
9. Use a clear humidity cover if needed. A transparent dome can help slow surface drying while still allowing light to reach the seed.
10. Ventilate regularly. Do not allow a humidity cover to create stagnant, continuously wet conditions.
11. Maintain surface moisture. Check the tray regularly because the surface-sown seed can dry quickly.
12. Remove the humidity cover after emergence. Once the majority of seedlings are established, provide unrestricted airflow.
13. Bottom water once roots establish. As the root system develops, switch primarily to watering from below.

Blackout

Do not use a conventional dark blackout period.

Celery seed responds positively to light during germination.

Avoid:

• opaque blackout lids;
• prolonged darkness;
• heavy weighting; and
• deep burial.

A clear humidity dome can be used temporarily if needed to help maintain surface moisture.

Germination

Expect germination in approximately:

7–14 days

Some seed may take up to approximately 21 days under slower conditions.

Celery naturally germinates less quickly and less uniformly than brassica microgreens, so gradual emergence is not necessarily a sign of poor seed.

Temperature

Aim for approximately:

20–24°C

Moderate warmth supports establishment.

Avoid excessive heat. Celery germination can be inhibited by high temperatures, and warm, stagnant, overly wet conditions also increase damping-off risk.

Light

Celery should receive light from the beginning of germination.

Once seedlings emerge, provide:

• bright indirect natural light or suitable grow lights;
• consistent daily light;
• gentle airflow; and
• protection from excessive heat.

Good light helps produce compact growth rather than weak, stretched seedlings.

Watering

Moisture management is particularly important because celery seed is surface-sown.

During germination:

• mist gently when required;
• keep the seed surface consistently moist;
• avoid allowing the surface to dry completely;
• avoid flooding the seed into clumps; and
• do not keep the tray saturated.

Once roots are established, bottom watering is preferable.

For more detail, see How to Water Microgreens: Misting vs Bottom Watering.

When bottom watering:

• add a shallow amount of water to the lower tray;
• allow the medium to absorb moisture from below;
• check moisture before adding more;
• do not leave the tray permanently sitting in deep water; and
• maintain good airflow.

Tips for Best Results

• Use approximately 3–5g per 25 × 50cm tray.
• Do not pre-soak.
• Surface sow the tiny seed.
• Do not bury deeply.
• Provide light during germination.
• Do not use a dark blackout.
• Maintain steady surface moisture.
• Use a clear humidity cover only when needed.
• Ventilate covered trays regularly.
• Expect gradual germination.
• Maintain approximately 20–24°C.
• Bottom water once roots establish.
• Allow the crop time to develop true leaves and strong celery aroma.

Common Problems

Celery can be more challenging than fast microgreens because of its slow germination and tiny surface-sown seed.

Common problems include:

• surface drying before germination;
• seed being washed into clusters by heavy misting;
• slow emergence in unsuitable temperatures;
• stretched seedlings from inadequate light;
• damping-off from excessive moisture and poor airflow; and
• uneven establishment.

For general troubleshooting, see the OzSprout Microgreen Problems: Yellow, Leggy, Wilting, Patchy or Falling Over guide.

Harvest & Storage

Harvest approximately:

21–30 days from sowing

Celery microgreens are best allowed to develop beyond the very early cotyledon stage.

Look for:

• healthy green foliage;
• upright stems;
• developing true leaves;
• a pronounced celery aroma; and
• the size and flavour you prefer.

Commercial celery microgreen guidance commonly places harvest at approximately 21–30 days, depending on the crop and desired stage.

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

Where practical, harvest when the foliage is relatively dry.

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

Growing as Baby Leaf

For larger celery leaves:

1. Sow much less densely than for microgreens.
2. Provide additional root and leaf space.
3. Continue growing beyond the microgreen stage.
4. Maintain consistent moisture.
5. Harvest tender young foliage once it reaches the preferred size.

Growing as Mature Celery

Tall Utah can also be grown through to mature celery plants.

For mature plants:

1. Surface sow or cover only very lightly when raising seedlings.
2. Keep the seed consistently moist during germination.
3. Provide adequate light.
4. Allow seedlings to establish before transplanting.
5. Transplant at approximately 20–30cm spacing.
6. Grow in fertile, moisture-retentive but well-drained soil.
7. Maintain regular watering throughout development.

Mature celery takes substantially longer to produce than microgreens.

Clean Growing / Food Safety

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

Maintain good airflow and avoid continuously saturated growing conditions.

At harvest:

• cut above the growing medium;
• keep roots and growing medium out of the harvested crop;
• use clean scissors or a harvesting knife; and
• refrigerate promptly.

Discard crops showing visible mould, slime, decay, collapsed seedlings or an abnormal smell.

Seed Storage

Store unused 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 the package to reduce condensation.