Shiso microgreens

Three of the five most expensive seeds in this directory are mint-family herbs: mint at $1,394.50 a pound, oregano at $242.36 and shiso at $155.50. The two that break the run are sorrel at $351.35 and watercress at $296.25, and basil Red Rubin follows at $93.40.

The cheap Lamiaceae here is chia at $12.48 a pound, and it is the exception that explains the rule: chia is a commodity food grain harvested for its seed by the tonne, while mint, oregano, shiso and basil are grown for leaf or propagated from cuttings. Seed price on this site tracks whether anybody farms the plant for seed at all. A sixth mint-family crop, thyme, joined on 2026-08-09 and cannot be placed on the ladder at all, because no supplier would quote a usable price for it.

Shiso is the only one of the top three you can actually cost. Mint and oregano both have expensive seed and no published seeding rate, so nobody can say what a tray of either costs. Shiso is in the Johnny's 29-variety trial with a measured rate, a measured yield and a stated harvest stage, which makes it the one place on this site where you can watch expensive herb seed turn into an actual tray economy.

The answer is $3.94 of seed, 6.5 ounces out, sixteen days. That is a slow, light, costly tray, and it is bought for flavor rather than weight.

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

Shiso microgreens are seedlings of Perilla frutescens, in the Lamiaceae. That makes it the fifth mint-family crop here, after basil, chia, mint and oregano, and unlike mint and oregano it is a genuinely documented tray.

"Shiso" is not one seed lot. Johnny's sells Britton as P. frutescens; True Leaf identifies its green shiso as P. frutescens var. crispa; the research literature separates green P. frutescens from red var. crispa. Buying "perilla" promises the species and nothing about the color or leaf you will get.

A correct Britton tray is a short, fairly delicate stand, not a thick brassica carpet: pale to silvery-green stems, round cotyledons giving way to ruffled, jagged true leaves, green on top with purple undersides. The supplier's own photograph shows mixed green and purple leaf faces sitting close to the medium rather than a uniformly purple sheet.

The harvest stage is the thing to get right, and it is later than you expect. Johnny's trial cut at first true leaf, at day 16. This is not a cotyledon crop, and cutting it at cotyledons gets you a fraction of the leaf and most of the wait.

Identification: the crop it gets confused with is purple basil, which is a reasonable mistake given they are in the same family and both sold as purple garnish herbs. The tell is the leaf shape rather than the color: shiso's true leaf is ruffled and jagged where basil's is smooth. That tell only works on Britton; green shiso has no purple underside to check.

What it tastes like, and what to do with it

Subtle licorice and anise with mint, basil and cinnamon behind it. It is an aromatic herb, not a mild green, and a small amount reads clearly on a plate.

That puts it on sushi and fish, in noodle dishes, in spicy Thai food, in cocktails and tea, and in desserts. It is the wrong crop for a bulk salad mix or a sandwich layer, where a few leaves stop reading as "green" and start reading as licorice.

It is polarizing and this page will not pretend otherwise. Anyone who dislikes anise, mint, basil or cinnamon notes will dislike this, and the same aromatic weight that makes it a good garnish will dominate a mild dish.

And it sharpens. The flavor turns spicier and more basil-minty as the tray ages, which matters more than usual on a crop this slow, and is the subject of the section below.

Growing it: only what differs from the standard method

The whole delta is patience and restraint. Nothing here is technically hard; it just takes two to four weeks instead of one, and the standard fast-tray habits are wrong at that length.

Sow evenly on the surface, press for contact, cover lightly. Light covering, vermiculite or a humidity dome, not burial. One supplier notes that shiso actually benefits from light during germination, which is part of why the blackout guidance is so unsettled.

Soak or do not. Two to four hours in cold water is the conservative published practice and the seed germinates unsoaked; one supplier says eight hours for uniformity. Nothing controlled has tested any of it.

The blackout guidance genuinely conflicts and you should know that before following either. One supplier says a weighted cover or dome for four to five days. A commercial schedule stacks under a 14 lb paver for three to four days at 70F, then keeps a blackout dome on for seven more, which is ten or eleven dark days. The weight is for seed-to-medium contact, not to force a stem, and growers report that too much of it for too long gives long, white, fallen stems. Take it off when seedlings start pushing the tray up.

After that, bottom-water and give it room. Wet foliage over a sixteen-day cycle is the problem this crop punishes. Johnny's own trial note is that larger harvests need more airflow and deplete water and fertility more slowly, which is the closest thing to a spacing instruction anyone publishes.

Light schedules conflict too: six to nine hours a day from one supplier, sixteen from another. No source gives a PPFD, a fan speed or a water volume for this crop, and none is invented here.

What goes wrong with shiso specifically

Uneven emergence, and growers blame the seed. Multiple grower reports describe roughly half a tray coming up, or emerging in waves, and at least one reports it resolving after changing supplier. That is a recurring observation rather than a measured lot-failure rate, but it is consistent enough that a counted germination test before a sixteen-day tray commitment is simply good arithmetic.

Stretch and collapse under the cover. Long, pale, spaghetti-like stems lying over the medium mean the weight stayed on too long or the dome stayed dark too long. Caught early it is recoverable: reduce the weight and give light.

Wet collapse. Growers describe a "goopy collapse" after too much water during the slow establishment. The general pathology behind it is the damping-off complex, Pythium and Rhizoctonia among others, which rots seedlings at or below the medium line. The usable field test is the stem base: firm stem with localized white fuzz on the roots is root hairs; a soft, pinched, water-soaked stem or a web spreading across the medium is disease. That test is general seedling pathology and has not been validated on shiso specifically.

And the slow one: holding it too long. Past first true leaf the plants keep going, the stand gets taller than the shallow-tray target, and the flavor moves toward the mature plant's spicy mint. It stays edible. It stops being the delicate thing you grew.

Nutrition, and what the studies actually measured

**USDA FoodData Central has no shiso or Perilla frutescens microgreen record**, checked 8 August 2026. Mature perilla values are not a substitute.

Two peer-reviewed studies exist and neither is a nutrition panel. One compared green P. frutescens var. crispa microgreens with germinated seed for macro and micronutrients and bioactive compounds, and reported quercetin-3-glucoside in the microgreen but not in the germinated seed. Another measured volatile compounds, total phenolics and antioxidant activity in red var. crispa and green var. frutescens microgreens against mature plants, under stated greenhouse conditions.

Those are cultivar, stage and system results. The claims circulating about shiso microgreens containing a specific amount of a vitamin, fiber or phosphorus, or having "three to five times" the antioxidants of the mature plant, are not supported by anything opened here. No crop-specific serving-value source exists.

Which seed to buy

Two verified microgreen offerings, and they are different products.

Britton is the documented one: silvery-green tops, purple undersides, ruffled two-tone leaf, and the only shiso with a measured rate, yield and harvest stage behind it. Johnny's listed it at $155.50 a pound on 8 August 2026.

Organic green shiso, P. frutescens var. crispa, is the tender jagged green type, listed by its supplier at 16 to 22 days. No controlled comparison of red against green for yield or tenderness exists, so this page does not offer one.

Specify food-crop microgreen seed, untreated, with the botanical or type name, a lot identity and a germination test date. One supplier lists its green perilla explicitly as not treated; another describes its offering as organic and non-GMO. Refuse seed labeled for treated field or ornamental use, because you are eating the shoot and nothing opened here clears those treatments for that.

So use the marketplace for a trial and buy the pound from a seed house if you are growing it for a buyer. The one thing Kitazawa does better is state seed counts, about 16,800 to the ounce for green and 25,000 for red, which lets you check a packet against the 11.5 g rate before you sow it. Ignore the $5 to $8 packets: those are 350-seed garden packets and nowhere near a tray.

Then test the lot. On a crop that occupies a tray for sixteen to thirty days, discovering a 50 percent germination rate on day twelve is the expensive way to find out.

Is it worth growing?

Grow it if you have a buyer. That is the honest version.

Shiso suits an intermediate grower or a chef with a specific use for a small aromatic garnish, who can accept a slow tray with expensive seed. At the measured figures it returns 6.5 ounces for sixteen days and $3.94 of seed, which is 1.65 ounces per dollar and 0.41 ounces per tray-day. Both are near the bottom of this directory's range.

It is a poor first crop for a beginner who needs quick, uniform feedback, and a poor choice for anyone paid by weight.

Its real competition is basil and other purple garnish herbs for the slow-herb slot, not radish for a fast bulk slot. Basil wins when you want a familiar sweet-herbal note or a more neutral green. Shiso wins when the plate wants ruffled two-tone leaves and a licorice lift. Against a fast crop there is no contest and no comparison worth making: Johnny's measured radish at 8 to 9.5 days and 8 to 11.5 oz against Britton at 16 days and 6.5 oz, all at first true leaf.

A note on the numbers above

Shiso is the fifth most expensive seed per pound in this directory at $155.50, behind mint at $1,394.50, sorrel at $351.35, watercress at $296.25 and oregano at $242.36, and ahead of onion at $113.30 and pak choi at $107.85. Three of the six Lamiaceae crops here are in the top five, which is the closest thing to a family-level economic pattern this site has found. The reason is the same one mint's page gives: these herbs are propagated from cuttings or grown for leaf, so almost nobody harvests their seed at scale and a pound of it is a specialty item rather than a commodity. The cheap one is chia at $12.48 a pound, which is not a counter-example but the proof: chia is farmed for its seed at commodity scale and is therefore cheap. The family does not make seed expensive. Not harvesting it does. The sixth, thyme, has no price anyone will publish.

What makes shiso worth the page is that it is the only expensive herb here that can be costed. Mint and oregano have the two priciest seeds on the site and no published rate between them, so their cost-per-tray cells are empty. Shiso's are not: $3.94 a tray, 1.65 oz per dollar, 0.41 oz per tray-day. Neither of the last two is a record, and both sit near the bottom of the range. That is the honest shape of an expensive slow herb, and it is only visible because somebody measured this one.

On the harvest window, shiso is the fourth crop this session to have the mechanism and not the measurement. Lettuce proposed that crops sold on flavor get short windows because the flavor sharpens, and named mizuna, mint, oregano, shiso, sorrel and thyme as the tests. Shiso plainly has the mechanism: its own suppliers say the flavor turns spicier and more basil-minty as it ages, and holding it past first true leaf is described as a quality loss rather than a weight gain. Nobody has measured how many days that takes. Four of the six named crops have now been researched and not one published a window. Sorrel and thyme are the last two chances, and the emerging answer may be that nobody measures hold time on herbs at all.

A blank means nobody has published that figure. Every crop here has a full research file; where no measured number exists this site leaves the cell empty rather than repeating an estimate. How the numbers work

All 61 crops, sortable, on the microgreen comparison.

Sources

• Shiso Britton microgreen seed, Johnny's - the cultivar description, the leaf and color detail, about 135,400 seeds per pound, and the $155.50 per pound price listed 8 August 2026.
• Johnny's microgreen yield trial summary and the trial tech sheet - Britton at 11.5 g, 6.5 oz and 16 days to first true leaf, plus the radish comparison and the trial's own caveat that one grower's system does not transfer perfectly.
• Organic green shiso microgreen seed, True Leaf Market and its wholesale growing guide - P. frutescens var. crispa, 16 to 22 days, the 8-hour soak claim and the 4-to-5-day covered period.
• Green shiso growers' notes, Paperpot Co - the 25-to-30-day commercial schedule, 17 g per 10x20, 160 g target, and the 14 lb paver sequence.
• Shiso microgreens, Epic Gardening - the 2-to-4-hour soak, the thick hull, the regrowth statement, and the over-held flavor shift.
• Micro shiso red specification, Fresh Origins - 6 to 7 days at 38 to 42F.
• Shiso/Perilla Green, not treated, Seedway - an explicitly untreated listing.
• Perilla microgreen composition, Food Chemistry - green var. crispa microgreens against germinated seed, and the quercetin-3-glucoside result.
• Perilla microgreen and mature-stage comparison, Horticulturae - volatiles, phenolics and antioxidant activity in red and green types under stated greenhouse conditions.
• USDA FoodData Central - searched 8 August 2026, no shiso microgreen record.
• Damping-off, UC IPM - the pathology behind the collapse growers report.
• Grower reports on r/microgreens describing uneven emergence and weight problems, goopy collapse, seed quality and a purple lot.