Broccoli microgreens are mild, slightly sweet and ready in 8–12 days. They are one of the most popular microgreens because they taste good on almost anything and are very forgiving to grow. The main thing to get right is the seed amount: broccoli seed is small, and it is easy to sow far too much.
Broccoli microgreens at a glance
| Seed per 10×20 tray | 18–25 g (about ¾ oz) |
| Soak | Not needed |
| Germination | 2–3 days |
| Blackout | 3–4 days |
| Light | 12–16 hours a day |
| Harvest | 8–12 days, at 1.5–2.5 inches |
| Flavor | Mild, fresh, slightly cabbage-like |
Choosing seed
Use untreated broccoli seed sold for microgreens or sprouting. ‘Calabrese’ and ‘Waltham 29’ are common, reliable microgreen varieties. Broccoli seed is often sold in bulk at a reasonable price, and because you need only about 20 g per tray, a pound of seed goes a long way.
Step 1: Prepare the medium
Fill a tray with drainage holes with about 1 inch of moist potting mix or coco coir, or lay a pre-soaked hemp mat in it. Broccoli grows evenly on any of these. Compare options in our growing medium guide.
Step 2: Sow — and don’t overdo it
Weigh 18–25 g of seed for a 10×20 tray. For smaller trays, scale the amount by area with the seed calculator.
Sprinkle evenly from a height of about 6–8 inches, which helps the seed spread. You should still see a little of the medium between seeds. Mist the surface well.
Over-sowing is the most common problem with broccoli: the seed looks sparse when you sprinkle it, so people add more. A dense mat of broccoli seedlings traps moisture and is prone to mold. Trust the scale.
Step 3: Blackout (days 0–4)
Cover the tray, or stack an empty tray on it with a pound or two of weight. Keep at 65–75°F (18–24°C) and mist daily if dry. Uncover when the seedlings are about an inch tall, usually on day 3 or 4. More in the blackout period guide.
Step 4: Light and water
Give the tray 12–16 hours of light a day. Bottom water about once a day, pouring off any excess after 10–15 minutes. Broccoli stays compact and upright under good light and rarely falls over unless it is under-watered or very crowded.
Step 5: Harvest (days 8–12)
Harvest when the cotyledons are fully open and green, before the first true leaves get large. At this stage the stems are tender and the flavor is mild. Stop watering the day before, then cut about ½ inch above the medium.
Broccoli microgreens keep about 5–8 days in the fridge when stored dry. See how to harvest and store microgreens.
What about the nutrition claims?
Broccoli sprouts and microgreens are often discussed in connection with glucoraphanin, a compound that the body can convert into sulforaphane. Much of the well-known research, starting with work at Johns Hopkins University in the 1990s, studied young broccoli sprouts (only a few days old) and found much higher concentrations than in mature broccoli heads.
Microgreens are older than sprouts and the levels vary with variety and growing conditions, so it is best to think of broccoli microgreens simply as a nutritious fresh vegetable rather than a supplement. Their real advantage at home is that you can have very fresh greens year-round.
Troubleshooting broccoli microgreens
| Problem | Likely cause | Fix |
|---|---|---|
| Mold patches in the middle of the tray | Too much seed, poor airflow | Use 18–25 g; add a small fan |
| Uneven germination | Uneven moisture or old seed | Mist evenly; test seed germination |
| Long, pale stems | Light too weak or too far away | Lower the light to a few inches above |
| Lots of seed hulls on leaves | Normal for some lots | Brush gently; most fall off by harvest |
| Yellow cotyledons after day 10 | Seed energy running out, or low light | Harvest sooner; increase light |
How to eat broccoli microgreens
Their mild flavor suits almost any dish: scrambled eggs, sandwiches, wraps, salads, grain bowls, smoothies and soups (added at the end, off the heat). They are a good “gateway” microgreen for people who find radish too spicy.
Frequently asked questions
Do broccoli microgreens taste like broccoli?
Mildly. They taste fresh and slightly like cabbage, without the strong flavor of cooked broccoli.
Should I soak broccoli seeds?
No. They are small and germinate easily dry. Soaked broccoli seed clumps together and is hard to spread.
Can I grow broccoli microgreens and sprouts from the same seed?
Yes. The same untreated seed can be sprouted in a jar or grown on soil as microgreens. See microgreens vs sprouts.
