How to Grow Microgreen Mix in Australia

Microgreen Mix is a blend of salad seeds from different plant families, grown thickly on a tray and cut young. It may include mizuna and radish (Brassicaceae), spinach and beet (Amaranthaceae), parsley (Apiaceae), basil (Lamiaceae) and cornsalad (Caprifoliaceae). The greens, commonly eaten raw, taste spicy, earthy and of basil, and are ready about 12 to 28 days from sowing.

Three mistakes that matter

1. Soaking the seed. Basil seed wraps itself in clear jelly within minutes of getting wet, so soaked mix sets into sticky clumps. Sow it dry onto damp mix.
2. Waiting for the slowest seed. Radish and mizuna can germinate in one to three days, parsley in a week or more. Held back for parsley, the fast growers turn bitter and fibrous, so cut when most of the tray is ready.
3. Leaving the cover on. Seed can go mouldy under a cover left on too long, or in mix kept too wet. Lift the cover once most of the seed has come up, and keep the mix moist, never soaked.

When to sprout

Microgreens grow indoors in any month, but the seeds in this mix want different warmth. Basil germinates from about 18°C, cornsalad prefers 10 to 20°C, and spinach and parsley falter above about 29 to 32°C. A room near 18 to 20°C suits them all. In trials, radish seedlings took about 11 days to appear at 10°C, against 3 days at 25°C.

On hot days, grow the tray in the coolest room; in winter, the warmest.

Food safety

The warm, damp tray that grows seedlings also suits bacteria, and washing may not remove them from the greens.

• Use untreated seed sold for sprouting or microgreens, as this mix is. Some garden seed is treated with fungicide. See which seeds to sprout.
• Wash your hands before you start. Wash and rinse the tray, cover and scissors, then sanitise them before the first batch and between batches. Use a dishwasher that can sanitise, usually on its longest, hottest setting. Otherwise, soak them in very hot water (77°C for 30 seconds). Or soak them for 30 seconds in plain unscented household bleach at 25 mL to 10 L of cold water. Make it up fresh each day and use it as its label directs. Let them air-dry.
• Wet the mix and water the tray only with water fit to drink, and start every tray with fresh mix.
• Bagged seed raising mix can carry Legionella bacteria, so follow the warning on the bag. Dampen the mix first, wear gloves and a P2 mask, and wash your hands afterwards.
• Keep cut greens in a fridge at 5°C or colder, stored above raw meat, poultry and seafood. Cooked greens for anyone at higher risk are eaten straight away. Leftovers are cooled, kept in the fridge, used within a day of cooking and reheated until steaming hot.
• Throw out any tray with mould, slime or a sour smell: compost greens and mix, and wash the tray. Greens can carry harmful bacteria while looking, smelling and tasting normal, so none of those is a test of safety. More in sprout problems and safety.

What you need

Grow in a shallow tray with drainage holes, standing in a solid tray for watering from below. Line it with kitchen paper so the mix stays in, and fill it with 3 to 4 cm of seed raising mix. Add a lid or an upturned tray as a cover, a spray bottle, clean scissors and Microgreen Mix seed. More on trays and light is in the microgreens article.

At microgreen density, the 300-seed packet covers only a small punnet, so it suits a pot of baby leaves (see Tips). For trays, buy by weight.

Sowing

Start with the mix wet through and the seed dry.

1. Line and fill the tray, then stand it in drinking water until the mix is damp right through. Let it drain.
2. Weigh the seed for your tray and scatter it evenly, thick but in one layer, not piled.
3. Press the seed in gently and dust it lightly with fine mix. Radish and parsley come up best covered.
4. Mist the surface once, put the cover on and keep the tray in the dark.

Under the cover, basil's jelly holds water, so mist only if the surface dries. In a hot, humid kitchen, lift the cover each day to let air in. Due to quarantine restrictions and our shipping policy, we cannot send Microgreen Seeds to Western Australia or Tasmania.

Day by day

Damp mix, dry leaves and moving air make a good tray. A fan on low, or a window opened by day, keeps humid air from settling.

To water from below, pour water into the solid tray and let it wick up; once the mix is wet enough, tip out the rest. Give it a bright spot out of direct summer sun; gentle morning sun suits it best.

Cutting and Storing

The tray is ready when most seedlings have open seed leaves and stand about 5 cm tall, even if the slow herbs are smaller. Snip radish that races ahead before its spiky first true leaf, and cut the rest a few days later.

• Cut when the leaves are dry to the touch; wet greens store poorly.
• Cut with clean scissors just above the mix, so no roots, seed or mix reach the bowl.
• Store them unwashed in a container with a few air holes; rinse just before use.
• Compost the roots and spent mix, and clean the tray as Food safety describes.

Refrigerate them as Food safety describes; they generally keep 5 to 6 days. Microgreens are commonly eaten raw on salads and sandwiches, or as a garnish. For anyone Food safety names, stir them through soup or a stir-fry until steaming hot.

Common problems

White fuzz on the roots. Root hairs form an even, bright white fuzz along the roots alone and flatten when misted. Mould can also be white, but it creeps unevenly across seeds, mix and stems like cobweb, survives misting and smells musty.

Clear jelly around some seeds. That is basil seed's natural coating, not mould.

Sour smell, slime or seedlings collapsing at the base. The mix stayed too wet in still air, sometimes with damping off (a fungal rot at soil level). End the tray and sow the next thinner.

Bare patches. Parsley may not be up yet; give it a few more days. Patches that stay bare may have dried under the cover.

Pale, stretched stems. The tray had too little light after uncovering, common in a dim winter kitchen. Move the next tray to a brighter window.

Small dark flies over the mix. These are fungus gnats (Bradysia species), which breed in damp mix and can arrive in the bag. Let the surface dry a little between bottom waterings.

Tips

1. For cut-and-come-again baby leaves, sow the mix thinly in a pot of potting mix, outside the hottest months. Cut leaves at 5 to 10 cm, about 2.5 cm above the mix, sparing the growing point, for three or four cuts. The Mesclun guide covers pots and feeding.
2. Sow a small tray each week for a steady supply.
3. Turn the tray half a turn each day so the whole tray gets light.