How to Grow Broccoli Sprouts in Australia

Broccoli (Brassica oleracea var. italica) belongs to the cabbage family, Brassicaceae, and its seed is sprouted in a jar and eaten raw. The sprouts are crisp, with a mild radish-like bite, and they are ready to eat 4 to 6 days after soaking. Most failed jars come down to one thing: water left sitting in the jar.

Three mistakes that matter

1. Leaving water in the jar. Seed sitting in a puddle between rinses turns sour and spoils. Drain hard after every rinse, then prop the jar mouth down at an angle so the last drops keep running out.
2. Starting with too much seed. Broccoli seed swells to many times its dry size, and a packed jar cannot move air through the middle. Keep to the amounts in What you need, so at least a third of the jar stays empty.
3. Putting sprouts away wet. Wet sprouts keep poorly in the fridge. Dry the surface first, as Harvesting and Storing describes.

When to sprout

Sprouts grow indoors, so any month suits them. Broccoli sprouts best at about 20 to 22°C and germinates across 15 to 29°C. Below that range the jar crawls along; above 30°C it can sour and turn mouldy before the sprouts are ready.

In Darwin's build-up to the wet season, sprout in the coolest room in the house and rinse three times a day. In a frosty July kitchen in Canberra, keep the jar away from cold draughts and allow an extra day.

Food safety

The warm, wet conditions that grow a sprout also grow bacteria, and bacteria carried inside a contaminated seed cannot be washed off.

• Buy seed sold for sprouting. Garden seed can be treated with fungicide or insecticide, and which seeds to sprout explains the difference.
• Wash your hands before handling seed or sprouts. Wash the jar, lid and bowl in hot soapy water and rinse them. Before the first batch and between batches, sanitise them in a dishwasher that can sanitise, usually on its longest, hottest setting. Without one, soak them in very hot water (77°C for 30 seconds). Or use plain unscented household bleach at 25 mL to 10 L of cold water for 30 seconds, made up fresh each day. Let them air-dry.
• Soak and rinse only in water fit to drink, and keep the jar away from raw meat and pets.
• Keep the fridge at 5°C or colder and eat sprouts within 4 days of harvest. Sprouts cooked 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.
• Sprouts can carry harmful bacteria while looking, smelling and tasting normal, so none of those is a test of safety.
• Throw out any jar that smells sour or musty, feels slimy or turns dark. More signs are in sprout problems and safety.

What you need

You need a wide-mouth glass jar, a mesh lid or muslin under a rubber band, and a bowl or rack to hold it mouth down. Add broccoli sprouting seed, plus a sprouting jar or mesh lids for mason jars if you need them.

A sprouting tray with a slotted base works too. Spread the soaked seed thinly, rinse it under the tap two to three times a day and let it drain. Empty the drip tray daily.

Soaking and Rinsing

Start in the evening, and the first rinse falls at breakfast.

1. Measure the seed for your jar and pick out any broken or discoloured seeds.
2. Rinse the seed in the jar, swirl and pour the water off through the lid. Some food safety services also suggest 15 minutes in white vinegar first, then a minute under the tap. That lowers the risk but does not remove it.
3. Cover the seed with two to three times its volume of room temperature drinking water, about 21 to 27°C.
4. Soak overnight, 6 to 12 hours, out of direct sun.
5. Drain, rinse once more, and drain hard.
6. Shake the seed along the side of the jar, then prop it mouth down at an angle in the bowl.

From then on, rinse two to three times a day with cool drinking water, and never soak the seed again. The angle drains water and draws air in through the mesh, keeping the seed damp but not wet.

Day by day

Drainage and air matter more than light, and ordinary room light suits the first days.

Direct sun heats the glass and can cook a jar, so green it near a window but out of the sun.

Growing as microgreens

The same seed grows into microgreens scattered over a tray of damp potting mix or a growing mat in good light. Potting mix can carry Legionella bacteria, so dampen it first, wear gloves and a dust mask, and wash your hands afterwards. Cut the microgreens with clean scissors when the first true leaves show, usually 8 to 12 days after sowing. The seed and root stay behind in the tray. The full method is in how to grow microgreens.

Harvesting and Storing

Broccoli sprouts are ready when most leaves have opened and turned green. Their dark seed coats, called hulls, loosen as the leaves open; remove them, because they shorten storage life.

• Tip the sprouts into a large bowl of cool drinking water.
• Loosen the clumps gently with your fingers so the hulls float free.
• Skim the hulls off the surface.
• Lift the sprouts out with clean hands or a slotted spoon.
• Repeat once or twice until few hulls remain.

Spread the sprouts on a clean cloth for 5 to 10 minutes, or spin them, until the surface feels dry. Pack them loosely into a clean, sealed container and refrigerate them straight away. Rinse each serve under cool running water just before eating. They go raw into salads, sandwiches and wraps, or cooked into soup or an omelette. For anyone named in Food safety, cook them until steaming hot.

Common problems

White fuzz on the roots. Root hairs appear on day 2 or 3, even and white along the root only, and they lie flat and vanish when rinsed. Mould can be white too. It grows in cobwebby patches on seeds and empty hulls, stays after a rinse and smells musty, and that jar goes in the bin.

Sour smell or slime. Any sign in Food safety means the jar has spoiled, and rinsing will not save it. Throw it out, wash everything and start again with the drainage in Three mistakes that matter.

Seeds that do not sprout. Old seed, seed stored somewhere warm or damp, a cold room or a jar kept too wet or too dry are the usual causes. Start again with seed stored cool and dry, in a room near 20°C, and rinse out any unsprouted seed with the hulls.

A matted, bluish root mass. Broccoli roots knit into a dense mat when the seed settles in one clump, and the batch keeps poorly. Shake the jar after every rinse so the seed spreads along the glass.

Bitter or chewy sprouts. Too much light or a jar left growing too long makes them tough. Keep greening to the last day or two and harvest while the sprouts are crisp.

Tips

1. Start a small jar every few days for a steady supply.
2. Store dry seed sealed in a cool, dark, dry cupboard, where it can keep for several years.