Nasturtium microgreens

Nasturtium is the crop whose own name belongs to a different plant.

Search "nasturtium" in USDA FoodData Central and the single hit is **FDC 170068, watercress, Nasturtium officinale. That is not this crop. The tray crop is garden nasturtium, Tropaeolum majus**, in the Tropaeolaceae, and it is not even in the same family as watercress. The plant that carries the name as its genus is a different vegetable with different requirements, and the one that everybody calls nasturtium is filed somewhere else entirely.

That is worth opening with because it is the most likely way to get this crop wrong before you have sown anything: by reading a nutrient panel, or a growing guide, for the other plant.

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

Nasturtium microgreens are seedlings of Tropaeolum majus, garden nasturtium. Family Tropaeolaceae, which makes this the first and only crop from that family in this directory.

The peppery flavor makes people assume it is a brassica, and it is not. It sits in the same broad order as the mustards and shares the glucosinolate chemistry that produces the heat, but the plant is unrelated to radish, arugula or mustard, and it behaves nothing like them in a tray: a huge seed, 7 to 14 days just to germinate, and three weeks to a cut.

A correct tray reads as a dense but individually legible canopy rather than a solid carpet. Each plant carries a round, shield-shaped leaf, veins radiating from near the center, on a substantial green to pink stem. Johnny's marketable stage is 3 to 6 inches tall with 2 to 4 leaves. Color varies by cultivar from lime to dusty green to purple-edged, so a universal stem-color description would be wrong. The large seed is often visible at the medium early on.

The confusion that matters is watercress, and the tell is the leaf: nasturtium's is a single round peltate leaf with veins radiating from near its center, where watercress carries compound leaflets. They are different families, different requirements and different flavors, and USDA's own search will hand you the wrong one.

What it tastes like, and what to do with it

Strong, peppery, and closer to horseradish or wasabi than to black pepper, with a brief sweetness before the heat arrives. This is a condiment crop. Nothing about it is mild.

That decides the use. Whole leaves and stems go where a plate wants visible volume plus a wasabi hit: sushi, spring rolls, sandwiches, composed salads, and as a finishing garnish on hot dishes. The leaf is the selling point as much as the flavor, because it looks like nothing else on the tray shelf.

It is the wrong choice as a salad base or in a mixed pack of mild greens. The leaves are large and the heat will dominate everything around it.

The people who will not like it are the people who dislike horseradish, wasabi or mustard heat. The objection is heat, not bitterness, which is a distinction worth making because it means the fix is portion rather than harvest timing. Nobody has run a panel on it.

Growing it: only what differs from the standard method

Everything general about trays, medium, light and watering is on the standard tray method for growing microgreens. Nasturtium departs in four ways, all downstream of a very large seed.

Sow a single non-overlapping layer, and cover it lightly. This is one of the few crops here that wants soil over the seed rather than surface contact: it needs darkness to germinate, and the published method is 1 to 1.5 inches of medium, seeds placed so they do not touch, a light press, and a thin layer over the top. That is the opposite of mint, which will not germinate if you cover it at all.

Soaking is optional and the sources disagree. Johnny's says it is not required, and a grower on camera agrees. Others specify 2 to 4 hours in warm water, 4 to 6 at room temperature, or a general 8 hours for hard seed. If you soak, 4 to 6 hours at room temperature and drain well before sowing. What nobody claims is that an unsoaked tray fails; the argument is about speed and evenness.

Three to four days stacked, and this crop has a real published weight. A farm crop sheet specifies a 14 lb paver on the top tray at 70°F, for seed-to-medium contact and downward rooting. That is worth flagging because most entries in this directory have no weight figure at all and have to say so. Take it off when the seedlings lift the stack.

Then keep it drier than instinct suggests. The failure on this crop is a big seed held wet under a cover while germination straggles. One supplier warns specifically against adding water in the first two days. After unstacking, the published regime is 16 hours of light a day and bottom watering once each morning, twice only if the medium will not hold moisture.

What goes wrong with nasturtium specifically

Before emergence: seed rot, and gaps you cannot fix. A wet covered tray plus a slow, staggered germination window. The early sign is soft or discolored seed instead of firm seed with a root showing. Individual seeds are not recoverable and reseeding into a running tray does not produce an even stand.

At emergence: damping-off. Thinning or pinched stems at or below the medium line and collapsing seedlings, Pythium and Rhizoctonia the usual organisms. A localised patch can be removed; a spreading tray is finished.

On the diagnostic, this page follows the evidence rather than the folklore. Root hairs occur on roots only, as a clean even fuzz, and do not spread across seed, stem or medium. What the extension literature actually anchors on is rot at or below the medium line and dying seedlings, not the whiteness of anything. If growth has spread beyond the roots and comes with soft seed, a water-soaked stem, odor or collapse, it is a failure regardless of color.

At harvest: the hulls, and on this crop they can cost you the tray. Seedlings frequently come up still wearing the seed coat. On a fine brassica that is invisible; on a seed this size it is obvious, and a premium garnish tray with hulls on the leaves is not sellable at garnish prices. There is a specific published remedy: wait a few days, mist the canopy, and briefly re-cover to loosen them. No retention percentage is published, so budget time for it rather than a number.

Late: it stops being a microgreen. Past four leaves the plant shifts toward a petite-green habit and starts drawing from the medium rather than the seed. It is obvious before you cut. No source measures what a day late costs in tenderness or flavor, so watch the leaf count.

Nutrition, and what is actually established

Nothing, for this crop at this stage, and the reason is worth stating precisely.

There is no Tropaeolum majus microgreen entry in USDA FoodData Central, searched 2026-08-09. The only "nasturtium" result is watercress. And no peer-reviewed composition study of nasturtium harvested as a microgreen was found at all. The research that exists is on mature leaves, flowers and extracts, which is a different plant part at a different stage and cannot be substituted.

So the vitamin claims on supplier pages have nothing behind them for this crop. That is not a debunk of nasturtium: the mature plant has real food chemistry and a long history of use. It is a statement about what has been measured on a 2-to-4-leaf tray crop, which is nothing.

This directory has been able to answer the nutrition question properly where the work exists, in both directions: lettuce has measurements showing the seedling beating its adult, celery has measurements going the other way, and mizuna has two studies showing the answer moves with the growing system. Nasturtium has none of that, and saying so is more useful than filling the space with adjectives.

Which seed to buy

Four named types are actually sold and they differ in color and schedule, not in a documented way in yield. Empress of India is the cultivar behind the only production record here, at 133 g and 21 days. Jewel Mix is variegated, claimed at 14 to 16 days. Blue Pepe is green with blue edges, claimed at 12 to 16. Emerald is a fourth. Tenderness and yield comparisons between them are not published, so buy on the look you want.

Ask for the lot and the germination test, and ask about seed size. This is the crop where the AeroGarden grower's observation matters commercially: a lot carrying two size classes soaks unevenly and emerges unevenly, and on a crop already published at 7 to 14 days to germination that reads as your fault rather than the lot's. No published germination specification exists for nasturtium microgreen lots, so ask the supplier for theirs rather than assuming one.

Refuse coated or fungicide-treated seed. NC State says plainly not to use fungicide-treated seed, often pink-coated, for microgreens. Nasturtium is widely sold as ornamental flower seed, which is exactly the channel where treated lots turn up, and "non-GMO" on a packet says nothing about treatment.

The marketplace is the expensive route on this crop, and the page says so rather than the reverse. The Amazon search returns 167 results with 41 nasturtium listings on page one, but only two are sold for microgreens: Whirlybird Mix at 4 oz for $21.03 and Empress of India, the exact production cultivar, at 1 oz for $11.81. Against the seed house at $1.22 an ounce for a pound, that is roughly ten times the price per ounce. The other 39 are garden and edible-flower seed of the same species, mostly untreated heirloom, which is a genuine option for one tray at 700 seeds for $15 to $17.

Is it worth growing?

For a chef, or for a home grower cooking like one, yes. For anyone selling by weight, no, and the numbers are unambiguous.

Nasturtium occupies a bench for 21 days and returns 5.64 ounces. That is 0.27 ounces per tray-day against sunflower's 1.79 and broccoli's 0.92. At $5.74 of seed it returns 0.98 ounces per dollar, which is the second-worst figure in this directory, behind only fennel. Both of those numbers say the same thing: this is not a crop you sell by the ounce.

What it is instead is the most visually distinctive thing in the category. A round shield leaf on a thick stem, with a wasabi hit, is a plated garnish that a restaurant will pay garnish prices for, and the commercial grower in the pulse block above is describing exactly that trade. Sold by the clamshell at a garnish price, three weeks and six ounces is a perfectly good business. Sold by the pound, it is a bad one.

Choose something else if you want speed, forgiveness, or volume. Its rivals for the peppery slot, radish, arugula and mustard, all beat it on every economic column and none of them looks like this.

A note on the numbers above

Both money figures rest on one farm's crop sheet, and that is the honest caveat on this page. The 133 g rate and the 160 g target come from the same document for the same cultivar. They are a real operation's numbers rather than a replicated trial, and this directory has been bitten before by treating two figures from one source as if they corroborated each other. They do not. What they are is the only crop-specific 1020 figures that exist for nasturtium anywhere, and the alternative is an empty row.

Nasturtium takes the second-worst value per dollar in this directory at 0.98 oz per dollar, behind fennel at 0.42. Chives held that place at 1.7 and now sits third. Unlike chives, which gets there through expensive seed, nasturtium gets there through quantity: the seed is only $19.58 a pound, which is unremarkable, but a tray swallows 133 grams of it because each seed is the size of a pea.

The pack size moves this tray more than most. At the 4 oz pack a home grower actually reaches for, the same tray is $10.07 of seed, which would be the highest figure in the directory; at 25 lb it is $2.75. That is a 3.7-fold swing on the bag alone, and it is the fourth crop here where that matters more than the species does.

The harvest window is blank, which as of 2026-08-09 covers 42 of the 46 entries written. The published harvest trigger is a leaf count rather than a date, and past four leaves the plant is documented to start drawing on the medium instead of the seed, which is a boundary rather than a window.

All 61 crops, sortable, on the microgreen comparison.

Nasturtium sits between cilantro and celosia on bench turnover and second from the bottom on value, which is a fair summary of the crop: it is not competing on either column and it does not need to.

Sources

• Johnny's Selected Seeds, nasturtium shoots key growing information - 14 to 21 days to marketable shoots at 3 to 6 inches and 2 to 4 leaves, 60 to 65°F minimum, 7 to 14 days to germination, soaking not required, single-layer sowing into 1 to 1.5 inches of medium with a light cover, and the Tropaeolum spp. label.
• Paperpot Co / Scintilla Farms, nasturtium microgreens grower's notes (PDF) - the only crop-specific 1020 figures anywhere: 133 g of Empress of India, a 160 g target yield, 21 days, 3 to 4 stacked days under a 14 lb paver at 70°F, 16 hours of light, morning bottom watering, and disposal rather than a second cut.
• True Leaf Market, Nasturtium Jewel Mix microgreen seed - the price ladder verified 2026-08-09 at 1 oz $5.78, 4 oz $8.59, 1 lb $19.58, 5 lb $61.64 and 25 lb $234.40, plus the 14 to 16 day claim and the variegated Jewel Mix description.
• Epic Gardening, nasturtium microgreens - 2 to 4 hours in warm water, non-overlapping seed under a thin soil layer, regrowth only where one or two leaves are left on the plant, up to 5 refrigerated days stored dry and unwashed, and the four-leaf boundary past which the plant draws on the medium.
• Mumm's Sprouting Seeds, nasturtium - 4 to 6 hour soak, visible germination in 4 to 6 days, the weighted empty tray for rooting, and the hull remedy: wait a few days, mist and briefly re-cover.
• Premier Seeds Direct, Blue Pepe microgreen nasturtium - 12 to 16 days, the slight sweetness before the peppery kick, and the warning that watering in the first two days raises the mold risk.
• Iowa State Extension, germination requirements - T. majus at 10 to 14 days to germination at an ideal 65 to 70°F in darkness, against broccoli's 4 to 7, which is the size of the difference.
• NatureServe Explorer, Tropaeolum majus - the taxonomy: Tropaeolaceae, not Brassicaceae, and not Nasturtium officinale.
• Penn State Extension, growing microgreens at home - the general 8 to 12 hour soak for large hard seed, and that washing before storage substantially reduces shelf life on delicate tissue.
• NC State, microgreens for school gardens - do not use fungicide-treated seed, often pink-coated.
• UC IPM, damping-off - Pythium and Rhizoctonia, and the diagnostic anchor being rot at or below the medium line rather than the color of any growth.
• USDA FoodData Central - searched 2026-08-09: no Tropaeolum majus microgreen record, and the sole nasturtium hit is FDC 170068, watercress.