Nasturtium microgreens

Nasturtium holds a bench for three weeks and comes off it with 5.64 ounces, roughly a quarter of what a brassica tray would have returned in the same space and time. What you get for that is a round shield-shaped leaf on a thick, pink-flushed stem with a wasabi hit, which is a garnish a restaurant will pay garnish prices for. Sell it by the clamshell and the arithmetic works. Sell it by the pound and it does not.

Three facts drive everything else on this page, and all three come from the seed being roughly the size of a pea. A 1020 swallows 133 grams of it. Germination straggles over 7 to 14 days, so a ragged stand is normal rather than your fault. And the seed coats frequently come up still stuck to the leaves, which on a garnish crop is a selling problem rather than a cosmetic one.

One trap before you buy anything: looking this crop up by name will hand you a different plant. The single hit for "nasturtium" in USDA FoodData Central is **FDC 170068, watercress, Nasturtium officinale, which carries the name as its genus and sits in another family entirely. The tray crop is garden nasturtium, Tropaeolum majus**, in the Tropaeolaceae. Check the Latin name on any nutrient panel or growing guide before you act on it.

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

Nasturtium microgreens are seedlings of Tropaeolum majus, garden nasturtium. Family Tropaeolaceae, and it is the only tray crop of any consequence from that family.

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 microgreen crops 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. Most crops leave you guessing at the weight, so use this one as given rather than approximating it. 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 localized patch can be removed; a spreading tray is finished.

Do not diagnose this crop by the color of the fuzz. Root hairs occur on roots only, as a clean even fuzz, and do not spread across seed, stem or medium. What the extension literature 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 has been measured on this crop at this stage.

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

So, the vitamin figures printed on supplier pages have nothing behind them here. The mature plant has real food chemistry and a long history of use; the 2-to-4-leaf seedling has simply never been analyzed. If you need a nutrition claim you can stand behind, for a label or for a customer who asks, do not make it on nasturtium. Lettuce, celery and mizuna all have real measurements, running in both directions against their adult forms.

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. 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 about as poor as tray crops get, with only fennel worse. Both 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, so treat them as a starting point rather than a benchmark. The 133 g rate and the 160 g target come from the same document for the same cultivar, which means they do not corroborate each other: two numbers from one source are still one source. They are the only crop-specific 1020 figures that exist for nasturtium anywhere, so weigh your own first tray and work from that afterwards.

The poor value per dollar comes from quantity, not from price. At 0.98 oz per dollar, only fennel at 0.42 does worse, and chives at 1.7 is close behind. Chives gets there through expensive seed. Nasturtium gets there through bulk: at $19.58 a pound the seed 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 the species does. At the 4 oz pack a home grower actually reaches for, the same tray costs $10.07 of seed; at 25 lb it costs $2.75. That is a 3.7-fold swing on the bag alone, so if you intend to run nasturtium regularly, the size you buy matters more than any growing decision on this page.

Nobody has established a harvest window, so use the leaf count instead. The published trigger is 2 to 4 leaves at 3 to 6 inches, and past four leaves the plant is documented to start drawing on the medium rather than the seed. That is a boundary, not a window: cut at the leaf count and note the date, and after two trays you will know your own holding time.

All 62 crops, sortable, on the microgreen comparison.

On bench turnover nasturtium sits between cilantro and celosia, and near 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.