Swiss chard microgreens are one of the most colorful crops you can grow on a shelf. Rainbow and ruby varieties give you red, pink, yellow and orange stems under bright green leaves, and the flavor is mild and earthy, a lot like baby beet greens. If you want to know how to grow Swiss chard microgreens, the short version is: soak the seed, sow it at a moderate density, give it 4 to 5 days of weighted blackout, then 6 to 10 days of light. This guide walks through every step with exact numbers for a standard 10×20 tray.
Chard is a little slower and a little fussier than fast crops like radish, mainly because of its odd, corky seed. Once you understand how that seed behaves, it becomes a reliable crop.
Key takeaways
- Use about 20–35 g of Swiss chard seed per 10×20 tray, and soak it for 4–8 hours first.
- Each “seed” is a cluster that can sprout several seedlings, so do not overseed.
- Keep trays covered and weighted for 4–5 days at 65–75°F (18–24°C).
- Harvest 10–16 days after sowing, when the first leaves are fully open and stems are colored.
- Seed hulls often stick to the leaves; a weighted blackout and a thin cover layer help a lot.
What makes Swiss chard microgreens different
Swiss chard and beets are the same species, and they share an unusual seed. What you buy as one “seed” is actually a dried, wrinkly fruit cluster that often holds two to four true seeds inside. That has three practical effects for microgreen growers:
- Germination is uneven. The corky shell slows water uptake, so some clusters sprout on day 2 and others on day 5. Soaking narrows that gap.
- One cluster can produce several plants. Sow chard a bit thinner than you would sow a single-seed crop, or the tray gets crowded and damp.
- Hulls cling to the leaves. The shell often rides up on top of the seedling. You will want a plan for that before you sow (more on it below).
If you have grown beet microgreens before, the process is nearly identical. If chard is your first “slow” crop, it helps to read our overview of how long microgreens take to grow so the extra days do not worry you.
What you need
- Swiss chard seed sold for microgreens (untreated). Ruby red, rainbow or “bright lights” types give the most stem color.
- One 10×20 tray with drainage holes, plus a second tray without holes for bottom watering, and a third to use as a cover.
- About 1.5–2 inches (4–5 cm) of a fine, moist growing mix such as coco coir or a peat-based seed mix. See our guide to the best growing medium for microgreens if you are choosing one.
- A weight of about 5–10 lb (2–4.5 kg) for the blackout stage, such as a bag of soil or a few books in a bag.
- A grow light or LED shop light on a timer.
- A spray bottle and a kitchen scale.
How to grow Swiss chard microgreens step by step
Step 1: Weigh and soak the seed (4–8 hours)
Weigh out 20–35 g of seed for one 10×20 tray. Start at the lower end (around 25 g) on your first tray; you can increase it once you see how many seedlings each cluster gives with your seed lot. Our microgreens seed calculator scales this amount for smaller or larger trays.
Soak the clusters in cool, clean water for 4–8 hours. Many growers go up to 12 hours with no problems, but longer soaks raise the risk of seeds starting to sour. Drain well before sowing. Our guide to soaking microgreen seeds explains why soaking helps hard-coated seeds like this one.
Step 2: Prepare the tray
Fill the tray with 1.5–2 inches of pre-moistened mix. It should feel like a wrung-out sponge: damp, not dripping. Level it and press it lightly flat with an empty tray so the seed sits evenly.
Step 3: Sow evenly
Spread the soaked clusters as evenly as you can. Aim for clusters that touch but do not sit on top of each other. Mist the surface well.
Optional but helpful: sprinkle a very thin layer of fine coco coir or vermiculite (about 1/8 inch, 3 mm) over the seed. This keeps the clusters moist and gives the seedlings something to push against, which scrapes many of the hulls off as they rise.
Step 4: Blackout with weight (4–5 days)
Place an empty tray directly on the seed and put 5–10 lb of weight on top. Keep it at 65–75°F (18–24°C). The weight improves seed-to-soil contact, helps the roots anchor and encourages strong, even stems. Check once a day; if the surface looks dry, mist it before replacing the cover.
After 4–5 days most seedlings should be about 1–2 inches tall and pushing the cover up. That is your signal to uncover. Read our microgreens blackout period guide for how to judge this moment on any crop.
Step 5: Move under light (6–10 days)
Pale yellow seedlings are normal right after blackout. Put the tray under your light for 12–16 hours a day, with LED lights roughly 6–12 inches (15–30 cm) above the canopy. The leaves turn green within a day, and stem color deepens over the following days. Strong light is what brings out the red and yellow stems, so do not keep chard in a dim corner.
Step 6: Bottom water
From this point, water from below. Pour about 1–2 cups (250–500 ml) into the holeless tray, let the mix wick it up for 10–15 minutes, then pour off what remains. Most trays need this once a day, sometimes every other day in cool rooms. Bottom watering keeps the leaves dry, which matters for chard because damp, crowded stems are where mold starts. Our microgreens watering guide covers how to tell when a tray needs water.
Step 7: Harvest (day 10–16)
Swiss chard microgreens are ready when the first pair of leaves (the cotyledons) is fully open and the stems are 2–3 inches (5–8 cm) tall with good color. That usually lands between day 10 and day 16 from sowing, depending on temperature and light. You can wait for the first true leaf to appear for a slightly stronger chard flavor. Cut just above the soil with sharp scissors. Our harvesting guide covers washing, drying and storage.
Swiss chard microgreens at a glance
| Stage | Swiss chard | Beet (for comparison) | Radish (fast crop) |
|---|---|---|---|
| Seed per 10×20 tray | 20–35 g | 20–35 g | 25–35 g |
| Soak | 4–8 hours | 4–8 hours | Not needed |
| Germination | 2–5 days | 2–5 days | 1–2 days |
| Weighted blackout | 4–5 days | 4–5 days | 2–3 days |
| Harvest | 10–16 days | 10–16 days | 7–10 days |
| Ideal temperature | 65–75°F (18–24°C) | 65–75°F (18–24°C) | 65–75°F (18–24°C) |
| Flavor | Mild, earthy, slightly salty | Earthy, sweeter | Spicy, peppery |
Seed rates vary between suppliers and seed lots, so treat these as starting ranges. For other crops, see our seed-per-tray chart.
Common Swiss chard microgreen problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Patchy, uneven germination | Corky seed clusters dried out or were not soaked | Soak 4–8 hours, add a thin cover layer, and keep the blackout surface damp |
| Hulls stuck on leaves | Seedlings lifted the shells instead of shedding them | Use weight during blackout, add a thin cover layer, brush hulls off before harvest |
| Weak or pale stem color | Too little light or harvesting too early | Give 12–16 hours of strong light and wait a few more days |
| Tall, floppy stems | Light too far away or blackout too long | Lower the light and uncover once seedlings lift the tray |
| White fuzz or bad smell at the base | Overseeding, overwatering, poor airflow | Sow thinner, water from below, add a small fan |
Not every white fuzz is mold. Fine, even white hairs on the roots are normal; read mold vs. root hairs to tell them apart. If stubborn shells are your main problem, our guide to seed hulls stuck on microgreens goes deeper into prevention and removal. For seedlings that will not come up at all, check why microgreens are not germinating.
How to harvest and store Swiss chard microgreens
Stop watering about 12 hours before harvest so the leaves are dry when you cut. Hold a handful of stems, cut about 1/2 inch above the soil, and drop them into a bowl. If hulls are still attached, swish the cut greens in a bowl of cold water; many shells will float free or sink. Spin or pat the greens completely dry, then store them in a lidded container lined with a paper towel in the refrigerator. Dry, unwashed chard microgreens usually keep well for about 5–7 days.
Chard microgreens do not regrow well after cutting, so plan on a fresh tray each time. Our article on whether microgreens regrow explains why.
Frequently asked questions
How long do Swiss chard microgreens take to grow?
Most trays are ready 10–16 days after sowing: about 4–5 days in blackout and 6–10 days under light. Cooler rooms push harvest toward the later end.
Do I have to soak Swiss chard seeds?
It is not strictly required, but soaking for 4–8 hours makes germination faster and more even because the corky seed cluster absorbs water slowly.
Can I grow Swiss chard microgreens without soil?
Yes, on hemp or other grow mats, but chard tends to anchor less firmly and shed fewer hulls without soil. A soil or coco coir mix is easier for beginners.
Why are my chard microgreens green instead of red or yellow?
Stem color depends on the variety and on light. Plain green chard varieties stay green; for color, buy ruby or rainbow seed and give the tray strong light for at least 12 hours a day.
Are Swiss chard and beet microgreens the same?
They are the same species and grow almost identically. Chard tends to taste milder, while beet microgreens are a little sweeter and earthier.
Once you have grown one tray, Swiss chard becomes a dependable way to add color to salads, sandwiches and plates. If you are still building your setup, start with our complete guide on how to grow microgreens and come back to chard once a fast crop has gone well.
