How to Grow Rocket: A Practical Guide from Seed to Harvest

Rocket is one of the quickest and easiest salad leaves to grow from seed, and you really don't need much space to get a useful crop. A short row in the garden is plenty, but it's equally happy growing in pots and containers on a patio.

It's also a good crop for sowing little and often. Rather than sowing a whole packet and ending up with more rocket than you can possibly eat for a fortnight, I prefer to sow a small amount every few weeks.

Rocket grows quickly in spring and autumn. It will grow through summer too, although hot, dry weather can encourage plants to flower and the leaves can become stronger and more peppery.

Keep the plants watered, pick the leaves while they're young and have another sowing coming along behind them.

When to Sow

Rocket can be sown from March through to September, and you can start a little earlier under cover if you want an early crop.

For most gardens, I'd start sowing outside from March or April once conditions begin to improve.

Make small sowings every two to three weeks rather than putting all your seed in at once. That way, as one batch starts getting older or runs to flower, you've got younger plants ready to take over.

During the hottest part of summer, a position with a little afternoon shade can be useful. Rocket tends to stay leafier for longer when it isn't baking in hot, dry soil all day.

Late summer and early autumn sowings can be particularly good. Cooler weather slows flowering and you can often get lovely tender leaves.

If you have a greenhouse or cold frame, you can extend the season even further.

How to Sow

Rocket is best sown directly where you're going to grow it.

Prepare the soil, make a shallow drill around 1cm deep and sow the seeds reasonably thinly.

Cover lightly with soil, gently firm and water if conditions are dry.

You don't need enormous rows. If you're only picking leaves for a couple of people, a short row can produce plenty.

For containers, fill a pot or trough with multipurpose compost and sow directly into it. Rocket doesn't need a particularly deep container, which makes it useful for patios and smaller spaces.

Keep the compost or soil moist while the seeds germinate.

Seedlings usually appear quickly when conditions are suitable, so rocket is quite satisfying if you're new to growing from seed.

Thinning and Growing On

Once the seedlings appear, thin them if they're very crowded.

If you're growing rocket mainly for baby leaves, plants can remain fairly close together. For larger individual plants, give them around 10–15cm of space.

There's no need to waste the thinnings. Once they're large enough, eat them.

Keep weeds away while the plants are small and make sure they don't dry out badly.

There isn't really much growing-on work involved. Rocket doesn't need potting on, staking or complicated feeding.

That's one of the reasons it's such a good small-space crop. Sow it, water it and start picking.

Growing Rocket in Pots

Rocket is an excellent crop for containers.

A wide pot, trough or window box works well because you're interested in producing lots of leaves rather than one enormous plant.

Make sure the container has drainage holes and fill it with good-quality multipurpose compost.

Sow a small patch, then consider sowing another container a couple of weeks later. By the time you've been picking heavily from the first, the second should be coming along.

Put containers in sun or partial shade.

During very hot weather, I prefer giving rocket a little afternoon shade. It can help keep the compost cooler and slow down the plant's enthusiasm for flowering.

The biggest thing to watch is watering. A shallow container can dry out remarkably quickly on a warm day.

Watering and Feeding

Rocket grows best when it has reasonably consistent moisture.

Plants that repeatedly become very dry are more likely to bolt and the leaves can develop a much stronger flavour.

Water thoroughly when necessary rather than giving the surface a quick splash.

Container-grown rocket needs checking more frequently, particularly during warm weather.

Feeding generally isn't necessary.

Rocket grows quickly and, in reasonable garden soil or fresh multipurpose compost, there's usually enough nutrition available for a crop.

If you're continually cropping plants from the same container for a long period, a little general-purpose liquid feed may eventually help, but I normally find it easier to refresh the compost and sow another batch.

Rocket is supposed to be a quick crop. I don't spend months trying to keep an exhausted plant going.

Harvesting

You can start harvesting as soon as the leaves are large enough to be useful.

For baby leaves, begin picking while they're still young and tender.

Either take individual outer leaves or cut a small amount from several plants, leaving the centre to continue growing.

Don't strip every leaf from a young plant if you want it to regrow.

Regular picking can give you several harvests, although eventually plants become tougher or begin preparing to flower. At that point, I usually let them go and move on to the next sowing.

Rocket leaves naturally have a peppery flavour, and this can become stronger as the plants get older or during hot, dry weather.

If you prefer milder leaves, pick them young and keep the plants growing steadily.

Succession Sowing

If there's one thing worth doing with rocket, it's succession sowing.

Sow a little every two or three weeks rather than relying on one crop.

This is particularly useful if you're growing in pots. You could have one container you're picking, another coming along behind it and then resow the first when it's finished.

It's a very efficient way of using a small space.

You can also fit rocket between slower-growing crops in the garden. Because it's ready quickly, you can often harvest it before neighbouring vegetables need the room.

For the Salads & Quick Crops section, this is exactly why rocket earns its place. You can get several crops from the same small area during one season.

Flowering

Eventually, rocket will produce flowering stems.

Warm weather, long days and dry conditions can speed this up.

Once flowering begins, the leaves usually become stronger in flavour and the plant becomes less useful as a conventional salad crop.

You can remove early flower stems and sometimes get a little more leafy growth, but I don't spend too much time fighting it.

I'd rather start another sowing.

The flowers are edible too and have a peppery flavour, so flowering doesn't necessarily mean the plant has become useless.

You can also leave some flowers for visiting insects and allow seed to develop if you want to collect it.

Common Problems

Flea Beetle

Small holes appearing across rocket leaves are often caused by flea beetles.

They can make the leaves look rather tatty, particularly on young plants. Keeping plants growing strongly helps, and fine insect mesh can be useful where flea beetles are a persistent problem.

The leaves are generally still perfectly usable once washed if the damage is only cosmetic.

Slugs and Snails

Slugs and snails can damage young seedlings, particularly during damp weather.

Keep an eye on freshly emerged plants until they're growing strongly.

Plants Flowering Too Quickly

Hot, dry weather is usually the main culprit.

Keep plants watered, use a little afternoon shade during very warm periods and keep another sowing coming along.

Once an older plant has decided it's flowering, I'd generally let it.

Leaves Becoming Very Peppery

Rocket is supposed to have some pepperiness, but older leaves and plants stressed by hot, dry conditions can become considerably stronger.

Pick younger leaves and keep plants regularly watered if you prefer a milder flavour.

Yellowing Leaves

A few older yellow leaves are nothing unusual.

If lots of foliage is yellowing, check for waterlogging, badly exhausted compost or overcrowded plants before automatically reaching for fertiliser.

Poor Germination

Rocket normally germinates readily.

Very cold, wet soil can slow early sowings, while freshly sown containers can dry out quickly during warmer weather. Keep the seed bed reasonably moist until the seedlings appear.

Rocket is one of those crops where you really don't need to make things complicated. Sow a short row or pot, keep it watered and start picking while the leaves are young. Then sow another batch. For a patio or small garden, it's difficult to find many crops that give you something fresh to eat quite so quickly.