Turnip microgreens

Turnip is one of the easiest trays you can run and one of the least documented. It germinates without a soak, it finishes in seven to twelve days, the seed costs about 31 cents a tray, and nobody has ever weighed a tray of it.

Sow 10 grams, cover for two to four days, take the cover off when the shoots are one to two centimeters and pushing it up, and cut at fully spread cotyledons at about two to three inches. That really is the whole method. The seed helps: at 320 to 380 to the gram it is coarse enough to place rather than dust, which is most of why beginners do well with it.

The one thing to get right is not holding it too long. Turnip is cut before true leaves arrive, and one source says the flavor changes sharply once they do. Watch the cotyledons rather than the calendar.

What it is, and how to tell you grew it right

Turnip microgreens are seedlings of Brassica rapa subsp. rapa. Purple Top White Globe is the one named cultivar found on a microgreen listing; the other labels opened are just the crop name.

The seed is bigger than you expect from a brassica, about 320 to 380 to the gram, which is roughly a thirtieth as fine as mint and coarse enough that you place it rather than dust it. That is most of why this is a beginner crop.

A correct tray is an even stand of pale stems with fully spread, bright green cotyledons, cut at about two to three inches. That is the whole specification, and all three crop-specific sources agree on it.

You cannot tell it from its siblings by looking, and on this crop it is worse than usual. Turnip sits in the same cotyledon-stage blur as komatsuna, tatsoi, pak choi and mizuna, and unlike those it is normally cut before true leaves arrive at all. So, the one stage that separates them is the stage turnip never reaches. The seed label is the identification.

What it tastes like, and what to do with it

Crisp and mild-sweet: cabbage and turnip, with a light pepper finish rather than a mustard bite. It is milder than radish and less assertive than arugula.

That makes it a salad and sandwich green with enough character to be noticed, and a reasonable choice for anyone who wants brassica flavor without heat.

Past the cotyledon window the flavor changes "dramatically", according to the supplier that says so, and no source opened here says in which direction or by how much. That is an unusually blunt warning with an unusually empty middle, and the practical response is simply to cut on time.

Growing it: only what differs from the standard method

Very little differs, which is the appeal.

No soak, stated outright by both crop-specific suppliers rather than merely omitted.

Sow about 10 grams and distribute deliberately. The seed is round and substantial enough to roll into hollows, so level the medium first. Go lighter if you intend to hold the crop longer.

Two to four dark days, and watch the crop rather than the calendar. The better instruction from the crop-specific page is to remove the cover and weight when shoots are 1 to 2 cm and pushing it up. A secondary source suggests around five pounds of weight; nothing crop-specific is published, and the weight's job here is even anchorage rather than stretch.

64 to 72F, then bottom-water and ventilate. That temperature range is the only one paired with an actual schedule by any source.

What goes wrong with turnip specifically

The failure is the one that follows from the crop being easy. Reliable germination on a substantial seed invites sowing thick, and a thick turnip stand held wet is the standard damping-off setup: rot at or below the medium line, then collapse in patches, from the usual Pythium and Rhizoctonia complex. Bottom-water and give it air.

Hulls ride up occasionally. The brown round coat can stay on the medium or cling to a seedling. Nobody has quantified it and it is not a sunflower-scale job.

And cutting late, which is genuinely under-specified here. Every source says harvest before true leaves and one says the flavor then changes dramatically, but the window between "cotyledons fully spread" and "too late" has never been counted. See below.

Nutrition: brassica-wide ranges, and nothing turnip-specific

No USDA FoodData Central record for turnip microgreens was located.

The nearest real evidence is a peer-reviewed 2016 study that assayed 30 Brassicaceae microgreen varieties for calcium, magnesium, phosphorus, sodium, potassium, copper, iron, manganese and zinc. Its accessible summary reports group ranges rather than a turnip row, and a 2023 review that appears to contain a turnip row could not be opened, so its values are not repeated here.

Brassica-wide ranges are not turnip nutrition facts, so do not quote one to a customer as though it were.

So, the claims to reject are the standard set: that turnip microgreens are "rich in vitamins C, K and A", that they contain a specified glucosinolate-derived compound, or that they deliver a named health benefit. Those may well be reasonable things to expect from a brassica. None of them has a turnip-specific measurement behind it.

Which seed to buy

Specify untreated seed sold for microgreen or food use, with a lot number and a germination date. Purple Top White Globe is the named cultivar with a microgreen listing; nothing establishes that it grows differently from generic turnip seed.

Do not take it. Cover-crop and wildlife-plot seed is frequently treated, is not handled as food, and its lot is not tested for a crop eaten raw at seedling stage. The saving is real and so is the reason for it.

The garden-seed price is cheap enough that the saving is not worth chasing. Mountain Valley's Purple Top White Globe at $13.90 a pound works out to 31 cents a tray, which undercuts mizuna at 39 cents and lentil at 47. Buy the pound: a 12 g garden packet at $5.99 would put $4.99 of seed in the same tray, which is the usual packet penalty and easy to avoid here.

One buying note. Several supplier pages quote turnip "from $8.45" without saying which pack weight that belongs to, so you cannot divide it by ten grams. Marketplace listings tend to state a weight, which is what makes the price above checkable. Insist on a stated weight before you compare anybody's seed price.

Is it worth growing?

Yes, for a beginner, and with an unusual caveat.

It is fast, it is forgiving, the seed is cheap and substantial, and the flavor is agreeable to almost everyone. As a first brassica after broccoli it is a sensible choice.

The caveat is that you will be growing it slightly blind. There is no measured yield, no measured harvest window, no usable seed price, and no turnip-specific nutrition. Its siblings mizuna, pak choi and tatsoi all sat in a real trial and have rate, yield and days pinned down. Turnip did not.

If you want the same easy brassica with numbers behind it, grow tatsoi: 7.5 g in, 8.5 oz out, 13.5 days, and every figure measured. If you want turnip specifically, grow turnip and weigh your own tray.

A note on the numbers above

The harvest window is described and never counted, which is an awkward thing to plan around. One source says plainly that there are "a few days" between the cotyledons spreading and the true leaves arriving, and that the flavor changes sharply after. That is a real observation of a real window with no number attached to it. So, cut your first tray as soon as the cotyledons are fully spread, leave the next two days longer, taste both, and you will have the number nobody published.

Treat the yield estimate as a target, not a benchmark. A supplier estimates about 300 g, which is 10.58 oz, and it is a round figure from the page selling the seed, with no method behind it. If your tray lands anywhere near that you are doing well; if it lands well under, that tells you nothing until you have weighed two or three.

Three numbers are missing on this crop and all three are about measurement rather than method. There is no measured yield, no counted harvest window and nothing on a second cut. The growing itself is well enough described that none of that should stop you: sow ten grams, cut at spread cotyledons, and keep your own figures. If you want a crop you can plan on paper instead, swiss chard has a measured rate, yield and day count from a single trial, while celery, popcorn shoots and thyme all have gaps of their own.

A blank means nobody has published that figure, so the cell is left empty rather than filled with an estimate. How the numbers work

All 62 crops, sortable, on the microgreen comparison.

Sources

• Turnip microgreens seeds, Deliseeds - the species, 10 g per 25x50 cm tray, 8 to 12 days at 18 to 22C, 2 to 3 blackout days with the 1-to-2-cm removal signal, about 320 to 380 seeds a gram, the 300 g yield estimate, the 3-day storage claim and the flavor description.
• Organic turnip microgreens, Golinucci - 8 to 10 days after 3 to 4 dark days, no soak, and the second flavor account.
• Purple Top White Globe untreated turnip seeds, Osborne - the one named cultivar on a microgreen listing, priced from $8.45 with no pack weight exposed.
• Turnip microgreens, Epic Gardening - 7 to 12 days at 2 to 3 inches, the roughly 5 lb weight suggestion, and the "a few days" harvest window with its warning to cut before true leaves.
• Johnny's microgreen yield trial and the trial tech sheet - 29 varieties, none of them turnip, which is why three of its siblings have measured figures and this crop does not.
• Mineral composition of 30 Brassicaceae microgreens, USDA-ARS record - the nearest real analysis, reporting group ranges rather than an accessible turnip row.
• USDA FoodData Central - no turnip microgreen record located.
• Damping-off, UC IPM - the wet-and-crowded risk this crop's easiness invites.
• Microgreens production, Virginia Cooperative Extension - the general 41F dark storage guidance and the single-cut treatment, neither used as a turnip figure.