"I'll buy regular seeds from the garden centre — cheaper and the same thing." Not the same thing. Seeds for outdoor growing may be treated with fungicides and insecticides — you will eat them along with the microgreens. Or germination rate is 60% instead of 95% — half the tray is bare, yield is unpredictable, the batch is ruined. Seed for microgreens is not "any seed of that crop." It is seed with specific requirements for purity, germination rate, and microbiological safety.
Quick glossary: Microgreens seed — seed material intended for germination and consumption as microgreens; must be untreated with chemicals and have a documented germination rate. Germination rate — the percentage of seeds that germinated under standard test conditions; for commercial microgreens production, an acceptable germination rate starts at 90–95%. Seed quality — a combined measure of germination rate, freedom from weed seed, microbiological safety, and absence of chemical treatment.
Why "Regular" Seed Does Not Work
Garden seed is treated in ways that are normal for growing mature plants but unacceptable for microgreens eaten whole 7–14 days after sowing.
Chemical treatment — fungicides and insecticides on the seed surface protect it from disease in outdoor growing. But when growing microgreens, these substances remain in the seedling tissue and end up on the plate. Treated seed is often dyed a bright colour — pink, blue, green — specifically to distinguish it from untreated seed. If the seed is coloured, it has been treated.
Unpredictable germination rate. Garden seed is sold with an acceptable germination rate of 70–80% — fine when plants grow for months and weak seedlings can be thinned. For microgreens where seeding density is calculated for 90–95% germination, a 70% lot produces uneven stands, bare patches, and underweight trays.
Microbiological contamination. Seed can carry pathogens — Salmonella, E. coli — especially if grown and stored without controls. For microgreens eaten raw this is a direct food safety risk.
What to Look for When Choosing a Supplier
A reliable microgreens seed supplier provides documentation for every lot: a germination certificate, confirmation that the seed is untreated, and ideally microbiological test results or an organic production certificate.
Practical criteria:
Specialisation. Suppliers who work specifically with microgreens understand the product requirements. A garden centre or general seed wholesaler often cannot provide the necessary documentation simply because they have never collected it.
Lot documentation. Every seed lot must have its own number and germination certificate. This is needed not only for quality — it is a traceability requirement under HACCP. If a customer complains about the product, you need to know which seed lot was used.
Test a new lot before placing a large order. Even with a trusted supplier, lots vary. Buy a small quantity, run a test sow, check germination rate and crop behaviour — then order the working volume.
Which Crops for Which Production Format
Not all crops are equally suited to every production format and market.
Fast and easy for the start — radish, mustard, rocket, cress. 6–9 day cycle, high germination rate, low-maintenance. Good for developing process.
Intermediate complexity — sunflower, pea, corn, wheat. Require soaking, longer 10–14 day cycle, but give higher tray weight and are popular with buyers.
Difficult or niche — basil, amaranth, fennel. Slow growth, sensitive to humidity and temperature, higher seed cost. Suitable once core processes are already refined.
Three Mistakes That Cost the Most
Buying the cheapest seed without checking for treatment. The price difference between treated and clean seed is often small — but the risk to product safety and reputation is disproportionately greater. Check the packaging and ask for documentation.
Not testing germination on a new lot before production launch. Seeding rate is calculated for a specific germination rate. If the new lot's germination is lower — every tray in that cycle will have bare patches and underweight yield. The test takes 3 days and saves a failed batch.
Storing seed without temperature and humidity control. Even high-quality seed with a high germination rate loses it under improper storage. Optimal: temperature 10–15°C, relative humidity 40–50%, airtight packaging or container. Seed bought "in reserve" for a year ahead and stored in a damp utility room is a guaranteed drop in germination rate.
How to Know the Seed Is Suitable for Production
Documentation is in hand: germination certificate ≥ 90%, confirmation of no chemical treatment. A test sow produced even stands with no bare patches by day 3–4. Seed appearance — natural colour with no bright dye. Smell is neutral with no chemical note.
For deeper understanding: Microgreens Seeding Rate: Logic, Not a Table from the Internet — the next step after seed selection: how to calculate how much to sow per tray.