Alys Fowler

Growing rocket

Rocket by name, rocket by nature. Growing distinctly spicy rocket leaves is a joy because this stuff loves to grow quickly.

September is the perfect (and last) time to sow some leaves for the rest of autumn and into winter. Its leaves are rich in vitamin C and potassium, and its pungent flavour works well with milder salad leaves such as lettuce and corn salad.

Rocket, Eruca sativa, is an annual plant that comes from the Mediterranean. Its leaves look a little like radish leaves and that's not surprising as they both come from the mustard family, Brassicaceae. It’s a distant relative of cabbage and broccoli and you can tell that from its four-petaled flower that resembles a cross and is typical of any member of that family.

It’s a great salad plant because it's easy to grow and abundant when happy. And more importantly for this time of year it doesn’t mind several degrees of frost, so it can be grown outside with minimal cover. Throwing a little fleece or a cloche over it during the worst of the weather is a good idea because it stops the leaves from becoming too tough and spicy. The harder the plant is grown, whether that is frost or lack of water, the spicier the leaves become until they taste like eating horseradish!

If you have a sheltered city garden or a corner next to the house that rarely sees any frost then this is the perfect place to grow it. I have a side-return extension by my back door that is the perfect microclimate for growing a few leaves for winter salads. It is bathed in mid morning sun and rarely gets a hard frost. Here I keep a couple of large containers just for salad leaves and garnishes so that I can pop from the back door straight out, even in the dark of winter nights and grab something fresh.

Rocket is very fast to germinate; just a few days and you’ll see little sprouts, which means you can grow indoors on a windowsill for micro greens. If however you want to be able to make repeated cuttings then you need to give each individual plant some space. Growing lots of seeds together in a small space just means that everyone competes with everyone else. For baby leaf, cut and come again; this is when you cut the leaves when they are around 10cm high, the seedling needs to be 5cm apart, but for plants that will grow bigger leaves and will survive the winter, then spacing needs to be around 15cm apart.

Rocket needs to be kept well watered, particularly if the weather is hot, otherwise it will bolt straight to flower. This often happens on the first few warm days in spring if you’ve been overwintering plants. Still there’s no loss here, the flowers are pretty, much loved by pollinators, particularly hoverflies, and are edible. They taste like a sweet version of the leaves. They are also very pretty; I always think they look like antique paper, white with grey, green veining.

There are two main types of leaf, either indented leaf or straight-leafed. As well as wild rocket, which is perennial and tends to have skinnier leaves that are even spicier, wild rocket is grown in exactly the same way as the salad rocket.

There are a number of varieties worth looking out for. Apollo is very fast growing, Pegasus is a UK bred variety that is very upright, which means the leaves remain cleaner over winter as they don’t sit on the soil. Rocket Dragon’s Tongue is a wild rocket leaf with red veining. It’s very pretty in a salad. Likewise the wild Rocket ‘Voyager’ has oak shaped leaves.