How to Grow Radish Microgreens
Page 1 of --
How to Grow Radish Microgreens
The fast, spicy, beginner-proof crop, grown like a pro: ready in days, with a peppery kick chefs pay up for.
Free Grower's Guide
Grown Like A Pro is a microgreen platform built by growers, for growers. This guide hands you the exact numbers we use on our own trays.
Start free at grownlikeapro.com/start
Let me ask you something. If you have never grown a microgreen in your life and you want a fast win, which crop should you start with?
Radish. Every time.
Here is why. Radish is the crop that almost refuses to fail. The seeds germinate fast and strong, the seedlings stand up on their own, and the whole grow is over before most other varieties have even greened up. You get a finished tray in about 8 to 10 days, start to cut.
So picture two new growers. One starts with a slow, fussy herb and quits after a moldy tray. The other starts with radish, pulls a clean harvest in a week, and is hooked. Which one do you want to be?
Master this one crop and you have proof you can grow. Let's grow it.
Start with radish seed sold for sprouting or microgreens. China Rose, Daikon, Sango, Triton, and Ruby Red are all popular. You want clean, untreated seed with strong germination.
Here is the first piece of good news for a beginner. Radish seed does not need a soak. Skip it entirely. The seed is small and germinates so eagerly that soaking just makes it gummy and harder to spread.
Radish seed is small, so you use less of it by weight than a big crop like sunflower. Here is the density we plant:
Spread the dry seed evenly across pre-moistened soil or coco coir. You want a dense, even single layer, with the seeds nearly touching but not piled on each other.
Radish is in a hurry, so the blackout is short and simple. After seeding, cover the tray to hold in moisture and darkness so the seed can germinate.
Stack a light weight on the covered tray for about a single day. A 5 to 7 lb weight is plenty. That little bit of resistance gives you straight, even, sturdy stems pushing up together.
That is the whole blackout. One short day under a weighted cover and you are ready to bring it into the light. Compared to slower crops, radish makes you feel like you are cheating.
By the end of that day you should see pale, crowded shoots reaching up and lifting the cover. That is your signal. Time for light.
Uncover the tray and move it under light for about 5 days. A basic full-spectrum LED shop light about 6 to 12 inches above the canopy, running 12 to 16 hours a day, is all you need.
Within hours of hitting the light, those pale shoots flush a vibrant green. With colored varieties like Sango, the stems hold their purple and pink while the leaves green up. This is the most satisfying stretch of the whole grow.
Hold the room in that comfortable 65 to 75 F range, keep a little air moving across the canopy, and your radish greens up fast and even.
Here is a question worth asking before your stems get tall and floppy: is my light close enough? Weak or far-away light makes radish stretch and go leggy as it reaches for more. Strong, close light gives you short, stocky, sellable stems instead.
If a radish tray fails, overwatering is almost always the reason. So let me reframe the whole thing for you. Your job is not to keep the tray wet. Your job is to keep it from drying out. Those are very different mindsets.
Stop watering on a schedule. Instead, pick up the tray. A watered tray feels noticeably heavy. When it feels light, water it. When it still feels heavy, walk away. Your hands learn this in about three trays.
Soggy, still, warm: that is the mold recipe. Bottom watering plus a little airflow keeps you on the safe side of it.
Here is the truth that took us a while to fully accept. With radish, growing it is the easy part. The decision that determines whether your tray sells or just sits is not your technique. It is your harvest timing.
Radish flavor is at its peak when the cotyledon leaves are open and vibrant and the very first true leaves are just starting to show. That lands around day 8 to 10. Cut it there and you get that clean, bright, peppery kick that buyers come back for.
The first true leaves starting to appear is your signal that the window is open. Wait too long past that and two things happen: the spice fades and goes flat, and the stems start to toughen. The crop that was a fast yes on the tongue becomes a forgettable maybe.
Tape this page to your shelf. These are the exact figures we grow by.
| Tray Size | Dry Seed |
|---|---|
| 10x20 | 35g |
| 10x10 (half) | 18g |
| 5x5 (one eighth) | 4g |
No unweighted blackout phase. Ready around day 8. Harvest through about day 10.
| Spec | Target |
|---|---|
| Soak time | None needed |
| Soil pH | 6.0 to 6.5 |
| Yield per 10x20 | about 340g |
| Blackout weight | 5 to 7 lbs |
| Harvest | day 8 to 10, true leaves starting |
Most of the time, fine white fuzz hugging the roots near the soil is root hairs. Totally normal, and radish makes a lot of them. The fast test: mist it. Root hairs flatten and vanish. Mold mats down but stays as a visible clump. Real mold spreads web-like across the surface and onto stems, and it smells musty.
If real mold shows up: improve airflow, stop overwatering, and spot-treat a small patch with dilute 3 percent hydrogen peroxide. If more than a quarter of the tray is hit, toss it, sanitize the tray, and replant.
Leggy stems mean not enough light, or light that is too far away, after blackout. Because radish grows so fast, this sneaks up on you. Drop the light closer, about 6 to 12 inches, and give a full 12 to 16 hours a day. Strong light makes short, stocky, sellable stems.
You almost certainly harvested too late. Past the window the peppery bite fades. Cut earlier next round, right as the first true leaves start to show.
Usually an uneven seed spread or dry spots in the medium. Spread the dry seed in an even single layer, and make sure the whole surface is evenly moist before you cover the tray.
The whole grow on one page.
| Stage | Day | What to Do |
|---|---|---|
| Plant | 0 | No soak. Spread dry seed evenly on moist medium, pH 6.0 to 6.5. 35g for a 10x20. |
| Weighted blackout | 0 to 1 | Cover and weight (5 to 7 lbs) for about 1 day. Mist lightly only if dry. Keep some airflow. |
| Light | 1 to 6 | Uncover. Light 12 to 16 hrs a day, 6 to 12 in above. Bottom water. Greens up fast. |
| Harvest | 8 to 10 | Cut when true leaves start, for peak spice. Stop watering 8 to 12 hrs before cutting. Expect about 340g per 10x20. |
You now know how to grow radish microgreens like a pro. Knowing it and doing it are two different things, and the doing is where the money is.
So here is the simple path forward:
Start free: grownlikeapro.com/start
Get the app and read the free full ebook at grownlikeapro.com/ebook/
Copyright 2026 Grown Like A Pro. All rights reserved.
Built by growers, for growers.