How to Grow Rocket (Arugula) in Australia

What is Rocket?

Rocket is a hardy annual herb in the brassica (cabbage) family, known for its strong peppery leaves with attractive serrated edges. Like all brassicas, rocket flowers and seeds with vigour, offering multiple harvests and tons of health benefits.

Rocket is exceptionally easy to grow, but does require regular maintenance as it grows quickly, so needs watering and feeding through a relatively short growing season, lasting around twelve weeks if regularly harvested.

In this guide, we’ll share details on getting the most of this cut-and-come-again crop, whether you’re growing it in containers, the ground, or hydroponics, as we’ve been doing with great success.

How to Grow Rocket 

Growing rocket isn’t difficult, but growing it well can be. Selecting the right site and the best conditions will depend on several factors, but there is nearly always somewhere you can plant rocket, regardless of where you live, and how shaded or nutrient-depleted your garden is.

Follow the growing guide below for details on providing rocket with its best conditions.

Best Conditions for Growing Rocket

Rocket will grow basically anywhere, provided it has at least 6 hours of direct sunlight per day, or 8-10 hours of dappled sunlight. Like all brassicas, rocket can grow in quite compacted soil, but likes rich, fertile substrates and a regular, steady flow of feed and water.

You can grow rocket outdoors, indoors, in pots, or in hydroponics, but in all cases, the more light, more water, and better nutrition it gets, the better flavour you’ll get as a result. But, as we’ll explain later, rocket has a stronger flavour if stressed for 24 hours before harvest.

How to Grow Rocket in Pots 

The easiest way to manage your rocket plants Is to grow them in pots. You can make sure the soil is fertile and packed full of compost at the time of planting, and regulate watering perfectly. Rocket can be sown directly in pots without the need to pot on or move plants around. 

Fill your pots with good peat-free compost, or a mix of sandy topsoil and compost for improved drainage if your compost is particularly coarse. Sow seeds 5-15 cm apart, and thin to 15 cm apart after germination.

Water plants well to maintain steady moisture levels, and start harvesting in about 6 weeks’ time.

Growing Rocket in the Ground 

Rocket grown in the ground will do just as well as rocket in pots, but you’ll need to manage weeds more thoroughly and prepare the soil in advance.

To prepare your beds for rocket, remove all perennial weeds, and add an inch-thick layer of compost to the growing space. Lightly dig the compost into the top soil with a hand fork. Water the bed to help it settle, and leave it for 24 hours.

Plant pre-grown plugs of rocket, sown a few weeks earlier, or sow directly into 1 cm-deep drills at 10 cm intervals. Harvests should be ready in around 8 weeks depending on the season, and will usually go on longer than rocket in pots.

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To extend your harvest season, re-sow or re-plant rocket every two weeks to make sure you have a healthy harvest of rocket all year round. In warmer parts of Australia, rocket can grow well outdoors, right through winter.

How to Grow Rocket Indoors

Rocket can be grown indoors, like any other herb. Simply prepare pots in an attractive window box for the kitchen windowsill. Fill each pot with 50% compost and 50% sandy soil, making sure the pots have a tray underneath, or a reservoir to keep water.

Thinly sow rocket seeds directly into the container, thinning plants to 10-15 cm apart as they develop (use thinnings in salads to avoid waste).

And for indoor and outdoor growers with any desire to try your hand at hydroponics, aeroponics, or tower gardening, rocket is probably the best way to get started. Rocket leaves can be sown directly into hydroponic systems, and work wonderfully in tower gardens.

Sow just as you would have for growing in pots, and you’ll have healthy, and especially crisp salad leaves in no time.

How to Grow Rocket from Seed 

Growing rocket from seed is incredibly simple. You can sow rocket at any time of the year, into pretty much any growing medium, and cover with roughly 1 cm of soil. Water it well, and keep it somewhere bright and warm. Germination takes about 4 days.

Sow rocket about 5 cm apart, and when planting out, or potting on, plant it 15 cm apart to allow space to grow.

Harvesting and Using Rocket

Rocket is ready to harvest when leaves are about 10 cm long, but it can be harvested younger for a sharper flavour, or if you are thinning out young plants to make room for others to grow.

You should generally start harvesting rocket after 6-8 weeks, when plants are looking bushy. Picking the outside leaves first, and letting the inside leaves develop.

Young rocket leaves can be bitter, and larger leaves have a milder flavour. If you want a stronger peppery flavour, let your rocket plants dry out for 24-48 hours before harvesting a big batch. That way you’ll avoid the bitter mid-sized leaves, and improve the mustard-like spice of the larger leaves. Water thoroughly after this harvest to avoid undue stress on the plant.

How to Harvest Rocket Seeds 

Rocket seeds are simple to harvest. Just let the plant bolt when a flower spike appears, and let nature take its course. Rocket seeds are similar to mustard seeds and packed with health benefits. Plus, they’ll provide you with next year’s crop if you dry and store them until needed.

Storing Rocket Leaves

Rocket stores quite well in the crisper drawer of the fridge, either in a paper bag or a sandwich bag with a few sheets of flat kitchen paper in the bag to absorb moisture. Rocket retains its texture for around a week in the fridge, and can be used like wilted spinach (but with more flavour) for up to two weeks.

Frequently Asked Questions About Rocket 

How big does rocket grow?

Rocket grows to 20 x 20 cm in height and width, occasionally larger if left without harvesting until just before flower spikes start bolting. Once flowered, rocket is around 1 m tall, and the leaves spread to 40-45 cm across. 

Will rocket continue growing after going to seed?

Garden rocket is an annual plant. The leaves, flowers and seeds are all edible, but once flowered the leaf texture becomes tougher, and the plant will begin to die back as seeds ripen.

Is wild rocket the same as rocket?

Wild rocket and garden rocket (also called common rocket, or just rocket) are different plants in the Brassica family. Common rocket (Eruca sativa), the subject of this article, is an annual plant. Wild rocket has a similar flavour and leaf shape but is a perennial plant, and a different genus and species (Diplotaxis tenuifolia).

What does rocket leaves taste like when harvesting?

Rocket leaves are peppery, and in the right conditions have more heat than their close relative mustard. The seeds have a wonderful spice too, and rocket flowers are slightly peppery, but with a delicate sweetness. 

How long does rocket grow before going to seed?

Rocket can grow for months and months without going to seed, but that generally requires cooler conditions than we can give in Australia. Typically, rocket grows for about twelve weeks of useful harvesting. With regular water, and protection from scorching sunlight, rocket can be grown for 8 months.

How do you harvest rocket so it keeps growing?

Rocket should be harvested as often as possible so it keeps growing. It is one of the most productive cut-and-come-again plants you can grow at home. Every time you harvest a handful of leaves, the plant puts more energy into producing new leaves. The more focused rocket is on leaf production, the less likely it will bolt.