How to buy microgreen seed, and what the label cannot tell you

One sentence carries most of the value here: buy a traceable, explicitly untreated lot, keep the lot number, and do not mistake "organic", "food grade" or a negative test for proof that the seed is clean.

Those four things get treated as interchangeable across this whole category and they answer completely different questions. Two of them are not certifications at all.

And the part nobody says out loud: there is no routine pathogen testing in the microgreen seed trade. Sprout seed has an FDA guidance document behind it. Microgreen seed does not, because a microgreen is cut above the seed and is regulated differently. That gap is real, and it is not the same as evidence that the seed is dirty.

"Food grade" is not a thing you can buy

This is the single most common misunderstanding on the subject, and it is worth being precise.

• "Food grade" describes the purity and authorized use of a food ingredient in US food law. It is not a seed grade, not a certification, and it names no certifier. A seller using it may mean untreated, or intended for human consumption, or nothing in particular.
• "Untreated" is a real and important claim, but it needs to be in writing and tied to a lot.
• "Organic" means organic rules were followed, including that prohibited substances were not used. It says nothing about pathogens.
• "Tested" means nothing without the organism, the method, the sample plan, the date and the lot number.

What US seed law actually requires on an interstate label is identity, germination and purity information, and disclosure of chemical treatment where present. That last one is the one that matters most.

The one hard refusal

Never buy dyed seed for a crop you intend to eat. Bright pink, orange, blue, green or red dust or coating is a warning color, and it normally means pesticide treatment. The official pesticide-safety position on treated seed is blunt: never consume it.

Do not reason your way around this by pointing out that you cut above the seed. The label decides what a treatment is approved for, not a tray experiment.

But the reverse does not hold: no dye is not proof of untreated. Priming, pelleting, coating and some treatments are not visible. The only reliable version is a written treatment statement, or a written "no treatment applied", attached to the lot number. Keep the packet.

Mint is the crop where this comes up most sharply in this directory: its crop-specific source states outright that pink or green dyed seed is not suitable for microgreens, because mint seed is otherwise so often sold into the ornamental trade.

What the one real study of microgreen seed found

In 2023, researchers bought 102 seed samples of 14 crop types from 26 online vendors and tested them. It is the only systematic look at this question, and its central finding is not the one you would expect:

Read that carefully in both directions. It is not a finding that borage, carrot and onion seed is unsafe, and it is not a clean bill of health for anything either. It is a finding that the crop matters more than the shop, which is close to the opposite of how this decision is usually framed.

Microgreens have been recalled, twice on record in the sources here, both for Salmonella, in Canada in February 2022 and by a US grocer in December 2022. Neither notice attributes the contamination to seed, and the US one reports that supplied soil tested positive. The full recall picture is here: five recalls, two countries, and zero illnesses across all five.

What 57 seed searches actually returned

Here is where this site can say something nobody else can. Every affiliate seed link on this site was added by opening the search and looking at it, never by trusting a result count, and the note on each one records what came back. That is 57 crops, and 25 of those notes record a problem with what the shelf actually offered.

Sorted, those 25 fall into a small number of shapes, and knowing which shape your crop is in tells you what to watch for.

The predictor, across all 57, is whether anybody sprouts the crop. Where a crop has an established sprouting audience the seed shelf is populated, honestly labeled and sold by weight. Where it does not, the shelf belongs to whoever else wants that species: cooks, gardeners, or farmers planting a field.

Two crops in this directory have essentially no microgreen seed product at all, and it is not a research failure: fennel and oregano each have exactly two verifiable microgreen listings from seed houses, with no published comparison between them. On those, buy the one that states its botanical identity, because that is the only distinguishing information that exists.

Germination: there is no standard, and you can test it yourself

There is no honest universal "microgreen seed must be X percent" figure, and anyone quoting one is quoting marketing. Germination is the share producing normal seedlings under ideal laboratory conditions, and a 95 percent broccoli lot is not a standard that onion, carrot or a dormant lot should be held to.

What to ask for is the supplier's own result for your lot: the percentage, the test date, and the method.

The home screen is genuinely easy and worth doing before you commit a schedule:

Two caveats worth having. Seven days undercounts a slow or dormant crop, so use the supplier's stated test conditions where you have them. And 50 percent is the practical point at which extension guidance says to plan on replacing the lot, not a legal threshold.

When a tray fails, run a split test before blaming the seed. Sow two counted samples from the new lot alongside a retained known-good lot of the same species, under identical light, temperature, density, water and tray. If only the new lot underperforms, the lot is the leading explanation. If both fail, look at the shared conditions first. A poor stand is not a diagnosis: saturation, density, sanitation and temperature all compete for the blame.

How long seed keeps, by species

Microgreen-specific seed longevity data does not exist. General vegetable-seed figures do, under ideal storage, and they vary by species by a factor of five:

Onion is the crop to watch on both counts, which is a coincidence worth noticing: it has the shortest storage life of the group and it is one of the three crops the 2023 study found carrying the highest microbial counts.

Store it sealed, dry, cool, dark and labeled. A refrigerator with a desiccant is the recommended version. Do not put an opened bag back into a humid grow room, which is the most common way a good lot becomes a bad one.

Price tells you nothing about quality, and this site can prove it

Across the 49 crops here with a costed tray, seed runs from $3.12 a pound for wheatgrass to $351.35 for sorrel, a 113-fold spread, and mint sits above all of them at $1,394.50 without being costable at all, because nobody publishes a rate to multiply it by.

That spread tracks whether anyone farms the plant for its seed, not quality and not suitability. Chia is cheap because it is a commodity crop. Mint is dear because it is propagated from cuttings and almost nobody harvests its seed.

And the price on the bag has never once predicted the cost of a tray in this directory. Wheatgrass has the cheapest seed here and one of the most expensive trays, because it takes 450 grams. Sorrel has near the dearest seed and an ordinary $2.71 tray, because it takes 3.5. Buy on the rate, not on the pound.

What to specify, and what to refuse

Ask for, in writing: crop and botanical name, intended raw microgreen or sprouting use, lot number, germination percentage with its test date and method, purity, a treatment statement, and storage history.

Refuse:

• Visibly dyed pesticide-treated seed. No exceptions.
• A seller who cannot identify the lot.
• Seed whose treatment label is incompatible with food use.
• A bulk bin or unlabeled repack with no traceability.

Do not refuse simply because a listing lacks a "food grade" badge. Ask instead for the records that the badge cannot replace.

On buying in bulk: it makes a good decision cheaper and a bad one repeat more often. One weak lot can fill a month of trays. Buy small, test, then scale, and keep the invoice, the label and a dry retained sample of every lot you run.

What nobody has measured

• Whether the seed trade tests at all. There is no representative survey of suppliers' written testing programs or lot records. The 2023 study bought product; it did not audit practice.
• Whether any recall traced to a seed lot. Microgreens have been recalled; no opened notice names the seed as the source.
• Microgreen-specific seed longevity, by species, under declared storage.
• A defensible sample size for a pre-scaling trial, which depends on seed size, expected germination and the money at risk.
• Any independent, blinded, same-lot supplier comparison. The pages that recommend suppliers are largely published by sellers, frequently with an affiliate relationship, and none of them is traceable to a trial.

Sources

Opened 2026-08-11. Seed prices and search results are this site's own, collected per crop and dated on each entry.

• Ocho Bernal, Lyttle and Jung, 2023, Frontiers in Sustainable Food Systems - 102 samples, 14 crop types, 26 online vendors, bought August to November 2022. Species was the significant factor; borage, carrot and onion highest at 4.99 to 5.37 log CFU/g; coliforms in 49 of 102; one onion Salmonella-positive and one carrot presumptive Listeria by PCR with no viable cells recovered; no significant organic against non-organic difference.
• National Pesticide Information Center, treated seed - what seed treatment is, the warning dyes, and the instruction never to consume treated seed.
• USDA AMS, Federal Seed Act and seed company records guide (PDF) - interstate label requirements including identity, germination, purity and chemical treatment disclosure, and what a lot record must hold.
• USDA AMS Seed Testing Program - the definitions of germination, viability and purity, and what a laboratory test does and does not report.
• FDA, determining the regulatory status of a food ingredient - the actual meaning of food grade in US food law.
• FDA final guidance on seeds used for sprouting (PDF) and its announcement - the controls that apply to sprout seed and not to microgreen seed, and the warning that a negative test cannot guarantee an unevenly contaminated lot.
• USDA organic seeds and planting stock practice standard - what an organic seed claim covers.
• University of Maine Extension, seed viability and the home germination test - species longevity under ideal storage and the paper-towel method, including the 50 percent practical threshold.
• University of Minnesota Extension, starting seeds indoors - airtight, cool, desiccant storage and declining germination over time.
• Canadian Food Inspection Agency recall, Arcadia microgreens and FDA/Wegmans recall - the two Salmonella recalls, neither attributing the source to seed.
• Agricultural Services Association v. Ferry-Morse - a documented seed mislabeling case, where an off variety yielded about half the expected crop.