How AgriZen Grows its Microgreens [A 10-Step Process from Cultivation to Delivery that we follow]

Before we delve into how we at AgriZen grow microgreens to supply to you, in case you wish to know in brief about what microgreens are, you may want to refer to our article on What Are Microgreens? A Complete Guide to Nature's Smallest, Most Concentrated Greens.

And now, we go straight to talking about every stage of microgreens cultivation from seed to harvest, what the research says about why each stage matters, and where AgriZen's specific choices (LED lighting, RO-purified water, an indoor grow unit rather than a farm) fit into the process.

Step 1: Choosing the Seed

Every microgreen starts out as the same seed you'd use to grow the full-sized vegetable, which raises a question most people never think to ask: what was actually on that seed before it went into the tray? Penn State Extension flags a detail that matters more than you'd expect here. Because microgreens are harvested so young, the seed coat itself sometimes persists on the seedling and gets eaten right along with it. A seed treated with an agricultural fungicide or pesticide, the kind meant for a field crop that'll be washed, peeled, or cooked long before anyone eats it, doesn't get that luxury on a microgreen. That's really the whole reason AgriZen only sources seed from a certified organic supplier, not as a claim about the harvested microgreen itself, but because this is the one point in the whole process where what's on the seed genuinely ends up on your plate.

This isn't just a Penn State recommendation. It's a standard position across university extension and state agriculture services more broadly. University of Minnesota Extension and Oregon State University's National Pesticide Information Center both state plainly that treated seed, seed coated with a fungicide or insecticide and typically dyed a bright colour as a warning, must never enter the food or feed chain. SDSU Extension makes the point specifically for this crop: because you're eating the young shoot itself, any chemical seed treatment could end up in what's on your plate, which is exactly why untreated seed isn't optional for microgreens the way it might be for a field crop that's fully grown, husked, or peeled before eating.

Step 2: The Growing Medium

Growers generally settle on one of two approaches here. Sow into soil or a soil substitute like coco peat, water it, and grow it under light, or skip soil altogether and germinate the seed on a soilless fibre or hemp mat, feeding it through the water instead. Penn State's growing guide actually has a preference: the hydroponic route tends to produce a cleaner harvest, since there's no soil or perlite clinging to the leaves at cutting time, which is a genuinely unpleasant thing to bite into if you've ever had it happen.

A broader review of indoor microgreens production, published in the journal Horticulturae, frames the choice of growing medium as one of the two most critical decisions in indoor microgreens cultivation, the other being lighting, since both directly affect photosynthesis, growth rate, and final yield.

Step 3: Sowing

Microgreens are sown far more densely than a normal vegetable crop, since the entire point is a thick, uniform stand of seedlings rather than individual well-spaced plants. Penn State's own production data, based on the microgreens course run at Pennsylvania State University, used 10 to 15 grams of seed per standard 12 by 20 inch tray, with commercial seed suppliers generally recommending 6 to 8 large seeds or 10 to 12 small seeds per square inch. Seed is broadcast evenly across the tray, sometimes topped with a thin layer of vermiculite or growing medium to keep it in even contact with moisture.

Step 4: Germination and Blackout

Once sown, trays are typically covered, often with a second tray and a light weight on top, and kept in the dark for two to three days. This blackout period keeps the seed pressed firmly into the growing medium and encourages even germination across the whole tray, rather than a patchy stand where some seeds spring up days ahead of others.

Step 5: Light

This is where AgriZen's approach diverges most clearly from a traditional outdoor farm, and where the research is most specific. Microgreens are classified as a low-light crop, needing a daily light integral under about 20 mol per square metre per day according to Penn State's figures, which is far less than a fruiting crop needs. But low-light doesn't mean unimportant: a 2024 study in Frontiers in Sustainable Food Systems found that light intensity measurably changes the antioxidant and phytochemical content of Brassica microgreens specifically, with the same study noting that a standard intensity for this family sits around 220 micromoles per square metre per second under LED light.

LED lighting is what makes this level of control possible in the first place. Because LEDs can be tuned for specific wavelengths and intensities and don't carry the heat load of older grow-light technology, they let a grower hold light conditions constant year-round, whatever is happening outside. Cloud cover, monsoon season, and winter's shorter days don't touch a crop grown under LED racks indoors. A review of artificial lighting for indoor microgreens production, also published in Horticulturae, specifically identifies LED lighting as central to the viability of sustainable, space-efficient indoor microgreens production.

Step 6: Water

Most commercial growers use sub-irrigation, watering trays from below via an ebb-and-flow system, rather than watering from above, since keeping the leaves and stems themselves dry reduces the risk of mould and disease. Water quality itself is a genuine food-safety variable, not a cosmetic one. The FDA's Produce Safety Rule requires that agricultural water, any water likely to contact the harvestable part of a crop, be safe and of adequate sanitary quality for its intended use, precisely because contaminated water is one of the more common routes by which pathogens reach fresh produce.

It's why AgriZen waters every tray with RO-purified water rather than untreated groundwater or municipal supply straight from the tap. It takes a variable that's otherwise outside a grower's control off the table entirely, so water quality reaching the crop doesn't shift depending on what's coming through the pipes that day.

Step 7: Temperature and Humidity

Penn State's guidance recommends soil temperatures of 60 to 75°F (16 to 24°C) for germination and air temperatures of 60 to 70°F (16 to 21°C) through the growing period. Microgreens will still grow outside this range, since the growing period is short enough that they can tolerate some stress, but consistent temperature is what produces a consistent crop, which is a large part of why indoor, climate-controlled growing is preferable to an outdoor setup where temperature swings with the weather.

Step 8: Feeding and Pest Management

Microgreens need very little fertiliser. Penn State's guidance suggests that where fertiliser is used at all, a solution of around 50 to 100 ppm nitrogen is generally sufficient, and notes that microgreens grow successfully with plain water too, occasionally showing iron-deficiency symptoms if grown that way for extended periods. There simply isn't enough time in a one-to-three-week lifecycle for a heavy feeding programme to make sense, and the same logic applies to pesticides: a treatment applied to a plant this young, grown indoors away from the insects and field pests an outdoor crop would face, has neither the time to be needed nor much reason to be applied in the first place.

This holds up in the research too, not just in AgriZen's own practice. A 2016 peer-reviewed review of microgreens production, published in Trends in Food Science & Technology, notes that growing indoors under controlled conditions removes much of the pest and disease pressure an open field creates in the first place. A 2025 life-cycle assessment of a related leafy crop put an actual number on that gap: open-field lettuce grown in California used up to 0.94 grams of pesticide per kilogram of lettuce produced, while the same study modelled indoor hydroponic production as needing none at all, precisely because the crop was never exposed to the pressures the pesticide would otherwise exist to solve.

The main disease risk growers watch for is damping-off, a fungal issue (commonly Rhizoctonia or Botrytis species) that thrives in warm, humid, poorly ventilated conditions. It's a good example of why a controlled indoor environment is an advantage rather than just a marketing point. Holding humidity and airflow steady is a solved problem indoors in a way it simply isn't in an open field.

Step 9: Harvest

Microgreens are ready anywhere from about 7 to 28 days after sowing depending on the variety, once the first true leaves have started to appear. Harvest means cutting the stem with a sharp blade just above the growing medium, leaving the seed and root behind entirely. Penn State's research found a genuinely practical trade-off here: growers using electric clippers can harvest a tray several times faster than growers using scissors, but the electric clippers tend to tear stem tissue rather than cut it cleanly, which shortens the microgreens' post-harvest shelf life. Precision costs time. AgriZen prioritises the cleaner cut.

Step 10: Cold Chain and Delivery

What happens in the hours after harvest matters almost as much as the growing itself. Penn State's research found that microgreens stored at 41°F (5°C) in the dark can hold for 10 to 14 days, compared with just 2 to 4 days at ambient room temperature, and that consistent humidity matters too, since temperature swings cause condensation that shortens shelf life further. It's also why AgriZen cuts and delivers on a short timeline instead of letting product sit around in transit or storage. Freshness at the point it reaches you is one of the few things that genuinely affects both flavour and how much of the water-soluble vitamin content, vitamin C especially, actually survives to your plate.

Why All of This Adds Up to Growing Indoors

Every step above has a version of the same theme running through it: microgreens respond measurably to temperature, light, humidity, and water quality, and an outdoor farm can only control one of those (arguably) while an indoor grow unit can control all four. A review of vertical farming systems, published via PubMed Central, makes this point directly: controlled-environment systems allow tighter control over light, temperature, and humidity, producing higher and more consistent quality while generally using less water and fewer inputs than open-field growing.

That's really the whole case for AgriZen's approach. Not that indoor growing is inherently superior in some abstract sense, but that for a crop this sensitive to its immediate environment, harvested this young and eaten raw, controlling that environment directly beats hoping the weather cooperates. It's what makes the crop consistent from batch to batch. Food safety follows the same logic: the FDA's Produce Safety Rule, which governs produce typically eaten raw, applies to microgreens as a category precisely because they skip the cooking step that would otherwise kill off surface contamination, which makes controlling water quality, growing medium, and handling all the way through genuinely important, not just good practice.

Frequently Asked Questions

How long does it take to grow microgreens?

Anywhere from about 7 to 28 days from seed to harvest, depending on the variety. Faster-growing varieties like radish and mustard are usually ready sooner than slower ones like sunflower or wheatgrass.

Do microgreens need soil to grow?

No. Soil or coco peat is one option, but many commercial growers use a soilless hydroponic mat instead, which tends to produce a cleaner harvest since there's no growing medium clinging to the leaves at cutting time.

Why does AgriZen use LED lights instead of natural sunlight?

LED lighting can be tuned to a consistent intensity and spectrum year-round, so the crop isn't affected by cloud cover, season, or weather the way an outdoor or greenhouse crop would be. Research on Brassica microgreens specifically has found light intensity affects their antioxidant content, so consistency matters beyond just growth speed.

Why RO water instead of regular tap or groundwater?

Agricultural water is a recognised food-safety variable under the FDA's Produce Safety Rule, since it's water that directly contacts the crop. RO purification removes a source of variability that's otherwise outside a grower's control, particularly relevant for a crop eaten raw and grown in a dense urban region.

Are microgreens grown indoors less natural than farm-grown produce?

It's the same seed, the same plant, and the same growing stages either way, just in a controlled environment rather than an open field. See Why AgriZen Grows Microgreens Indoors, Not on a Farm for the fuller case.