Zone 5 · Microgreens Growing Guide

How to Grow Radish Microgreens

The fastest microgreen — bold, peppery flavour ready in 5–7 days. One of the easiest crops to grow and a great entry point for microgreen beginners.

Plant window opens
Indoors year
Last chance to plant
Last frost
~Apr 15
Days to harvest
5–7 days
Difficulty
Easy
Ready to harvest — Zone 5
Harvest: Year-round

Planting Calendar

Indoor tray crop — no outdoor space or frost dates needed. Ready to harvest in 7–14 days on a windowsill or under a grow light.

Indoor year-round. No soaking needed — sow dry directly on growing medium.

Growing Journey

Here is what to expect at each stage — and what to do when you get there.

SowingDay 0-1

Sow densely and evenly. Mist thoroughly, cover with a blackout lid or second tray, and press down firmly to ensure seed

GerminationDay 1-4

Leave covered and check moisture daily. The weight of the tray on top helps seeds develop straight, strong stems.

Blackout PhaseDay 2-5

When shoots are pressing against the blackout cover, move to light. The stretch in darkness builds stem length.

Growing in LightDay 4-12

Water from below by setting the tray in water and allowing it to absorb upward — this avoids mould on the surface. Harve

What to Expect

Typical yield
One tray yields 50-200g depending on variety and tray size

At peak: Ready in 7-14 days — the fastest crop you can grow

Microgreens are instant gratification — from seed to harvest in under two weeks. Perfect for getting children interested in growing.

Key factorssowing densityblackout timingbottom watering technique
Get notified when to sow, water, and harvest your Radish Microgreens.
Grown Radish Microgreens before?or

Care Guide

Sunlight
Full sun to partial shade · 3–8 hrs/day
Watering
Regular
Spacing
See notes
Soil
Seed-starting mix or coco coir
Days to harvest
5–7 days
Soil pH
6.0–7.0
Plant tip · Zone 5
Radish microgreens are the best crop to start with — they germinate in 24 hours and are ready in less than a week. Sow densely and keep the blackout lid on until you see the seed hulls rising.
How to know it's ready
Harvest at 5–7 days when cotyledons are fully open and bright purple-pink. Don't wait — radish microgreens turn bitter and tough quickly. Cut at soil level with scissors.

Watering Radish Microgreens

How often
Mist 2–3 times daily during germination; once or twice daily once in light
How much
Keep growing medium moist but never waterlogged
Method
Bottom watering or fine mist — top watering can cause damping off
Overwatering signs
Grey mold, foul smell, stems rotting at base
Underwatering signs
Dry crispy sprouts, slow germination, wilting seedlings

Feeding Schedule

How often
None required
Feed type
No fertilizer needed
Key timing
N/A

Microgreens draw all their nutrition from the seed and growing medium. No fertilization needed for 5–7 day crops.

Succession Planting

Sow every 1 weeks

Sow a new tray every 1-2 weeks year-round indoors. Each tray is a single harvest — cut at soil level when seed leaves are fully open. Keep 2-3 trays going at different stages so you always have something ready.

Direct
Sow seeds densely (cover tray surface) on damp growing medium. No soaking needed. Cover with second tray for 2–3 day blackout phase, then move to light.
Container friendly
Grown in shallow 10×20 inch trays — standard propagation trays work perfectly. No minimum gallon requirement.

Common Problems

Something went wrong? Here is what likely happened and what to do differently next time.

White fuzzy mold on the surface

What happened: Surface mold is caused by overwatering or poor airflow. It is different from the white root hairs that are completely normal and healthy — root hairs are orderly and attached to stems, mold is fuzzy and appears on the soil surface.

Next season: Water from below by setting the tray in water — never mist the surface once seeds have germinated. Ensure good airflow around the tray.

Seedlings fell over at the base

What happened: Damping off is a fungal condition that rots the stem at soil level. It is caused by overwet, poorly ventilated conditions — especially in the blackout phase.

Next season: Do not overwater during germination. Ensure the growing medium is moist but not wet before sowing. Improve airflow once seedlings emerge.

Seeds did not germinate evenly

What happened: Patchy germination is usually caused by uneven seed contact with the growing medium, or the surface drying out during germination. Larger seeds like sunflower and peas benefit from pre-soaking.

Next season: Press seeds firmly into the surface after sowing. Soak larger seeds for 8 hours before sowing. Ensure the medium is thoroughly moist before you start.

Seedlings stayed yellow and pale

What happened: Microgreens kept in blackout for too long become etiolated — pale, stretched, and weak. Once moved to light they should green up within hours. If they do not, they have been in darkness too long.

Next season: Move to light as soon as shoots are pressing against the blackout cover — usually day 3-5. They green up fast once in light. Do not wait until they look fully grown under the dome.

Wilted or crispy after moving to light

What happened: Microgreens dry out fast under grow lights or in a sunny window. They need consistent moisture from below during the light phase.

Next season: Water from below once a day during the light phase — set the tray in a shallow dish of water for 10-15 minutes and let it absorb upward.

Pests & Diseases

Know what to look for before it gets out of hand — early identification is the most important step.

What to look for
Tiny flies around trays; larvae damage roots and stems at soil level
Cause
Overwatering creating wet growing medium
Organic treatment
Allow medium to dry slightly between waterings; yellow sticky traps
Prevention
Don't overwater; use clean growing medium; bottom-water where possible
What to look for
Seedlings collapse at soil line, stems thin and water-soaked
Cause
Overwatering, poor airflow, contaminated medium
Organic treatment
Improve airflow; reduce watering; discard affected tray and start fresh
Prevention
Use clean trays; don't overwater; sow at correct density; ensure airflow

Recommended Varieties

  • Daikon (white, mild — classic microgreen variety)
  • China Rose (pink/purple, spicy — most popular)
  • Triton Purple (vibrant colour, intense flavour)
  • Sango Purple (deep purple, beautiful presentation)
China Rose is the most widely grown radish microgreen — reliable germination, consistent pink colour, and excellent spicy flavour.
Crop Rotation — rotate every 0 years
Indoor crop — rotation not applicable
Avoid planting after: N/A
Good to follow: N/A
Indoor tray crop — no rotation needed. Clean trays between batches.

Storing Your Harvest

Room temp
1–2 days after harvest
Fridge
5–7 days in a sealed container lined with paper towel
Freezer
Not suitable
Harvest and refrigerate immediately. Do not wash until ready to eat. The paper towel absorbs moisture and prevents rapid deterioration.

Free app · Kickstarter October 2027 · iOS February 2028

Know exactly when to plant, prune, and harvest Radish Microgreens

plant uses your ZIP code and real frost data to tell you the right day — not just the right month. Get notified when your planting window opens, when to succession sow, and when to cut back for next season.

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Common questions

Radish Microgreens is an indoor tray crop — no zone or frost dates needed. Sow densely on damp growing medium, blackout for 2–3 days, then harvest at 7–14 days when cotyledons are fully open.
Zone 5 has an average last spring frost around Apr 15 and a first fall frost around Oct 15. These vary by location — the plant app uses your ZIP code with NOAA data for precision.
See companion planting section above.
Radish Microgreens typically takes 5–7 days to harvest in Zone 5. Expected harvest window: Year-round.

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Microgreens