Four brassicas in equal parts, grown two completely different ways from the same bag. In a jar it is a five-day sprout — mild and cabbagey with a light peppery lift. In a tray of soil it is a microgreen with lavender and violet stems under a green canopy, and that is the version worth growing for the look of it. One of the four behaves differently when it is soaked, so page 2 is worth reading before your first jar.
Two ways to grow it
- You need
- A quart jar and a mesh lid
- Seed
- 2 level tbsp — about 23 g — per quart jar
- Soak
- 6 hours, once — the short end, on purpose
- Ready
- Day 5
- Yield
- About 4½× the seed weight — 3½ oz a jar
- Colour
- Mostly green and pale — see the note below
- Taste
- Mild and cabbagey with a light peppery lift
- You need
- A shallow tray, potting mix, a bright window or a shop light
- Seed
- 12–15 g per 10×20 tray
- Soak
- None — sow it dry
- Ready
- Day 10–16
- Yield
- 8½–11½ oz of cut greens per tray
- Colour
- Lavender and violet stems, purple veining in the leaf
- Taste
- Sweeter and greener than the jar version
The four seeds in the bag
Four brassica seeds in equal parts by weight — whole, untreated, uncoated, and grown for sprouting and microgreens rather than for the field. Untreated is why the disinfection step on page 5 is yours to do if you want it. Every lot is germination tested before it is packed, and nothing goes into the bag but seed: no paper, no ink, no coating. They are all small, hard, round, dark seeds and they look nearly identical dry — you will not pick the four apart until they are growing, and then only by the stems.
Two of the four carry the colour, and most of it is in the stem. Red Acre cabbage gives a purple stem with purple veining and margins on a dark green leaf; purple kohlrabi gives a purple stem with a purple cast through the leaf. Broccoli stems run green and mizuna stems run white — neither adds anything. By seed count the two coloured varieties are just under half the bag, so grown as microgreens you get roughly half the stems in lavender to violet under a canopy that reads green overall. Cut a handful and lift it and the colour is unmistakable; look straight down at the tray and it reads green with purple showing through. In a jar it is thinner again — some purple in the stems and leaf margins, with the middle of the jar staying pale because no light gets to it. We would rather say all that here than have you lift the cover expecting a purple lawn.
Jar sprouts — five moves
Soak
Put 2 level tbsp in a clean quart jar with a mesh lid. Rinse under running water for a minute, cover with cool water, leave 6 hours — the short end, on purpose. Soak once and never again.
Drain
Pour the water off and rest the jar mouth-down at 45°. These seeds are small and round, so they pack into a mat that holds water in the middle. Draining hard is the whole skill.
Rinse
Every four hours or so, fill, swirl hard to break the mat, pour off, drain fully, return to the angle. Three times a day is the floor, not a target — more in a warm kitchen.
Green Up
Move the jar into indirect light, never a sunny sill. Leaves open and colour over a day. The sprouts buried in the middle stay pale whatever you do — that is the jar, not the seed.
Harvest
Pick when most leaves are open and green. Rinse, skim the hulls, drain very well, refrigerate once they are dry to the touch.
Broccoli, red cabbage and kohlrabi are ordinary jar-sprouting seeds. Mizuna is a mustard, and some mustards go slightly slick when wet — you may see a faint slime on the seed through the first day. It is nothing like chia, basil or cress, which throw a true gel sack around the seed, and at one seed in four against three that do not do it at all, the jar should behave much like any brassica mix. True Leaf Market lists mixing a mucilaginous seed into non-mucilaginous seed as one way of handling it in a jar — the other way, and the one they call the most common, is to skip the water method and grow it in a tray. What that means at your sink: soak at the short end, six hours rather than overnight, and on the first couple of rinses fill generously, swirl hard, and keep pouring off until the water runs clear rather than syrupy. Any slickness clears over the first day or two of rinsing. This blend is new, and the jar is the part we most want to hear about — if you get more slime than this describes, switch to a tray or shorten the soak, and tell us what you saw.
What each day looks like
Pick your sprouting method
- 2 level tbsp in a sanitized quart jar; mesh sprouting lid, or cheesecloth under a canning ring.
- Rinse under running water a minute, disinfect if you are going to, then soak 6 hours.
- Drain completely; prop mouth-down at 45° in a bowl or dish rack.
- First two rinses: fill generously and pour off until the water runs clear.
- Then rinse at least three times a day, swirling hard. Day 4 into light; harvest day 5.
- Soak in a separate jar or bowl — trays are for growing, not soaking.
- Rinse the soaked seed thoroughly before it goes on the tray; that clears any slickness in one pass.
- Spread in a thin, even layer across the tray.
- Set over the drip pan with a slight tilt so water runs off.
- Water gently three times a day and let it drain right through. Harvest day 5.
- Bag: soak in the bag in a bowl, lift, drip, hang over the sink.
- Dunk in cool water three times a day and hang to drain.
- Colander: soak in a bowl, drain into a fine colander, cover with a damp towel.
- Rinse under the tap, shake dry, re-cover.
- Uncover on day 4 for light; harvest day 5.
Harvest, store, and eat
- Skim the hulls. Fill the jar, swirl hard, and pour off the hulls that float — two or three passes. Brassicas shed a great many, and they are where spoilage starts.
- Dry them well. The step people skip. Drain well after the final rinse, spin in a salad spinner, or roll in a clean towel.
- Container. Loosely covered, or a bag with a paper towel. Not sealed airtight while damp.
- Fridge at 40°F or below once dry to the touch. Best inside a week.
- Toss anything dark, slimy or sour-smelling, without deliberating.
- Sandwiches and wraps — the default, and where the light pepper does its work.
- On top of anything hot — soup, eggs, rice. At the table, not in the pan.
- Slaws and grain bowls — the cabbage and kohlrabi suit both better than a plain green does.
- As a garnish — the one that earns its keep. Cut microgreens laid across a plate show the purple stems properly.
- Stir-fried hard — the cooked route needs real heat, not a token warming.
What an 8 oz bag gives you
Sprouts or microgreens — which should you grow?
| If you want… | Jar sprouts | Soil microgreens |
|---|---|---|
| The purple | Thin and patchy — the middle of the jar never sees light | This is where it shows: roughly half the stems lavender to violet, with purple veining in the leaves |
| Effort | Three rinses a day for five days, no equipment | Sow once, cover, uncover, bottom-water, cut once |
| The mizuna | Short soak and a couple of hard rinses to clear any slickness | Does not arise — trays are sown dry |
| Food safety | Sprouts carry a specific FDA advisory. Page 5 covers it properly | Cut above the soil, outside the sprout-specific rules. A different exposure, not a sterile one |
Questions we get a lot
Before your first jar — checklist
Reseal it and keep it cool, dark and dry — a pantry is fine, a freezer is better. Never return damp, soaked or disinfected seed to the bag; treat only what you are about to sprout.
Growing it as microgreens
Same seed, different crop, and for this blend the better one. Microgreens grow in a shallow bed of soil, get real light, and are cut above the soil line — so you eat stem and leaf, not root and hull. It is also the only way to see what the blend actually looks like, because the purple is in the stems and a jar hides them.
| Item | What works | Notes |
|---|---|---|
| Tray | 10×20 nursery tray, or any shallow food-safe container | 1–2″ deep. A tray with drainage holes sitting inside a solid tray is ideal, because it lets you bottom-water |
| Medium | Potting mix, seed-starting mix or coco coir | Fill about 1½″ and level it flat — a low spot stays wet, and a wet spot is where the tray rots |
| Seed | 12–15 g per 10×20 tray, sown dry | Weigh it. Johnny’s measured trials seed these four at 9.5–13 g a tray; commercial charts go as high as an ounce, which crowds the tray and invites damping off |
| Cover | An inverted tray, a board, or a cake pan | Weight it lightly — a few pounds. Resistance drives the roots down and gives a straighter tray, but mizuna is a fine-stemmed mustard and the heavy weights used for peas and sunflower will crush it |
| Light | A bright window, or a shop light 6–12″ above | More light after the blackout gives more purple than skimping does. You do not need a special grow spectrum — in one controlled trial, adding red or blue to white light did not raise anthocyanin in red cabbage microgreens. A plain shop light is enough |
Microgreens — five moves
Sow
Level moist soil in the tray. Scatter 12–15 g of dry seed evenly — dense, single layer, in two passes at right angles. Weigh it. Press gently, do not bury, water in from the top once.
Blackout
Cover and weight it lightly. Check at 48 hours. The published blackout windows for all four overlap, so they come off together — the mizuna may be a shade behind, which is fine.
Uncover
Once the seedlings lift the cover, take it off. They will be pale yellow; bright light greens them in a day and starts the purple showing in the stems.
Water
Bottom-water only from here — into the outer tray, let it drink, drain the rest. Water sitting on these leaves is what brings damping off.
Cut
Harvest at 1½–3″ with the seed leaves fully open and the first true leaf barely showing. Cut just above the soil — roots, hulls and most of the seed stay behind.
What each day looks like
Cutting and keeping
- Cut dry. Skip the watering the morning you harvest. Dry greens keep far longer than damp ones.
- Sharp scissors, just above the soil. Take a handful, cut, set it in a bowl.
- Usually no washing. Bottom-watered greens never got dirty. If you do rinse, dry them completely first.
- Store in a paper-towel-lined container in the fridge; best within five to seven days.
- One cut only — they do not regrow. Compost the mat and re-sow.
In Johnny’s measured trials the average days to maturity were mizuna 12, broccoli 12½, red cabbage 13½, and purple kohlrabi about 16 — the clear laggard, though other growers rate kohlrabi faster, so treat it as the variable one. In a blended tray that makes the last few days a judgement call rather than a date. Cut when the majority has fully opened seed leaves and accept that a minority of kohlrabi will be shorter. Waiting for it to catch up costs you the broccoli and mizuna, which go tough and sharp once true leaves start.
Food safety — the part that matters
Sprouts have a food-safety history that other fresh produce does not. We would rather give you the mechanism than a warning label.
Disinfecting seed at home
Read this first. FDA’s position is that seed treatments “may reduce, but not eliminate, pathogens on seed for sprouting.” CDC is blunter: “Cleaning or disinfecting contaminated seeds before sprouting does not eliminate the risk of contamination.” Pathogens can sit inside the seed, where nothing you do at a sink reaches them — which is why no agency treats this as a kill step. It is still worth doing, and almost nobody does. Do it right before the soak, on the portion you are about to sprout.
| Method | How | Notes |
|---|---|---|
| Heated hydrogen peroxide | 3% hydrogen peroxide held at 140°F, seed immersed 5 minutes in a mesh strainer, swirled each minute, then rinsed a full minute under running water | K-State Extension’s home method. Hold it at 140°F the whole five minutes with a clean, accurate thermometer — do not let it drop, and do not let it run hot. Discard the peroxide after each batch; it weakens quickly |
| Dilute bleach | 1 part unscented household bleach (about 6% sodium hypochlorite) to 9 parts cool water. Soak 15 minutes, then rinse very thoroughly under running water | Not an extension method — it comes from a 2023 peer-reviewed trial of home options, which found it the most effective while leaving germination intact. Measure it, never use it neat, rinse until there is no smell, and test a small batch first |
| Undiluted vinegar | Soak in undiluted white vinegar for 15 minutes, then rinse thoroughly | The simpler alternative, also from K-State. Acetic acid can knock germination back, and K-State’s own advice is to test a small amount of seed first if that worries you |
The rest of the routine
- Rinse at least three times a day, or roughly every four hours — that is the extension floor for home sprouting, not a target. More in hot weather.
- Keep it near 70°F. Heat is the accelerator, and extension guidance is explicit about not sprouting through summer without temperature control.
- Sanitize the jar and lid between every crop, not just rinse them — 3 tablespoons of unscented bleach per quart of water, five minutes, then rinse with clean water. Or boil for ten.
- Drinkable water only, at every stage.
- Rinse the seed under running water for a minute before the soak, and skim off anything that floats — seed-coat fragments and debris are where contamination concentrates.
- Refrigerate at 40°F or below as soon as they are dry to the touch, and eat them inside a week.
- Cook sprouts thoroughly if you want the kill step. CDC is direct: thorough cooking kills the harmful bacteria.
- CDC and FDA advise that children, older adults, pregnant women and people with weakened immune systems avoid eating raw sprouts of any kind. Lightly cooked counts as raw here.
- Throw out anything that smells sour or musty, looks slimy, or that you are unsure about. It is two tablespoons of seed.
Grow it as microgreens instead of sprouts, or cook it thoroughly. Those are the two honest answers, and with this blend the first one is also the better crop. A microgreen is cut above the soil, so the roots, most of the hulls and the ungerminated seed stay in the tray, and in the federal produce rules a crop cut that way falls outside the sprout-specific requirements. Not sterile, and not risk-free — seed-borne contamination still applies. But it is a genuinely different exposure, and everything else on this page reduces risk rather than removing it.
Something went wrong
| What you see | Why it happens | What to do |
|---|---|---|
| Slippery first rinses | The mizuna. Some mustards go slick when wet, and it reads alarmingly like spoilage on day one. It has no smell, which spoilage does. | Fill generously, swirl hard and keep pouring off until the water runs clear. It clears over the first day or two. If it keeps up or starts to smell, start over with a tray |
| A solid mat or plug | Small round seed knits into a felt that water cannot get through. Almost everyone hits this. | Shake the jar hard at every rinse, not gently — the mat has to actually break apart. If it keeps happening, use less seed or switch to a tray |
| Sour or fermented smell | Water trapped in the middle of that mat, too much seed, or a warm kitchen — usually all three. | Drain far harder at a true 45°, keep it near 70°F, cut back to 2 level tablespoons. If it genuinely smells bad, throw it out — do not rinse it and carry on |
| Fuzzy white growth | Almost always root hairs, and brassicas produce them in quantity. Bright white, fine, evenly spread on the root tips, no smell. The rinse test settles it: root hairs collapse and vanish under water; mould does not. Mould is coarser and patchy, spans several sprouts, and smells musty. | If you are not sure, throw the batch out. And note what this test is not: it finds mould and spoilage only. Salmonella and E. coli do not change how a jar looks, smells or tastes |
| Hulls all through the crop | Normal, and brassicas shed a great many of them. | Fill the jar, swirl hard, pour the floaters off the top, repeat two or three times. Worth doing — hulls shorten fridge life |
| Still pale on day 5 | No light. Sprouts grow perfectly well in the dark, they just never colour up. | Indirect light for a day and keep rinsing. The ones buried in the middle stay yellow regardless and taste the same |
| Not much purple | Two of the four make purple and only in the stem. In a jar most of it is hidden; in a tray, weak light gives weak colour. | Grow it in a tray and give it plenty of light after the blackout. Expect lavender stems and purple veining under a canopy that reads green — not a purple crop |
| Tray: tall and floppy | Too long under the cover, or not enough light after it comes off. | Uncover as soon as the seedlings lift it, check at 48 hours, and get the tray brighter |
| Tray: collapsing at soil level | Damping off — favoured by excess moisture, high humidity, crowded seeding, still air, and by cool medium. Below about 68°F before the seed germinates raises the risk. | Bottom-water only, fresh medium and sanitized trays every cycle, good air movement, and keep the medium around 70–75°F rather than cool. Stay at 12–15 g a tray rather than seeding heavier |
| Tray: uneven heights at day 12 | The kohlrabi. In Johnny’s trial data it averaged about day 16 while the other three came in between 12 and 13½. | Cut when the majority has fully opened seed leaves. Waiting on the kohlrabi costs you the broccoli and mizuna, which go tough and sharp once true leaves start |
Before your first tray — checklist
Reseal it and keep it cool, dark and dry — a pantry is fine, a freezer is better. Never return damp, soaked or disinfected seed to the bag; treat only the portion you are about to sprout. Stored properly these four keep for about three to four years, with germination and vigour declining gradually rather than falling off a cliff.