Onion 'Stuttgarter Riesen' (Spring Planting)

Where to Plant

Plant Onion ‘Stuttgarter Riesen’ in an open, sunny position with fertile, moisture-retentive but well-drained soil. Before planting, remove weeds and improve poorer ground with well-rotted garden compost or other well-rotted organic matter if needed. Avoid fresh manure.

If your soil is heavy and slow to drain, wait until conditions improve before planting or grow your sets in a raised bed or large container.

Onions prefer soil that isn't strongly acidic. If you know your soil is acidic, test its pH before adding garden lime and apply lime only if needed, ideally well ahead of planting.

Planting

Plant each set with the pointed end facing upwards, so the tip is just showing above the soil surface. Space ‘Stuttgarter Riesen’ sets around 10–15cm apart, with 30–45cm between rows, then gently firm the soil around them and water well.

When to Plant

Plant ‘Stuttgarter Riesen’ sets from March to April. If early spring conditions are particularly cold and wet, wait until the soil is workable rather than planting into saturated ground.

Growing in Containers

‘Stuttgarter Riesen’ can also be grown in a large container with good drainage. Fill with a good-quality peat-free compost, position in full sun and give the sets enough room for the bulbs to develop without becoming crowded. Container-grown onions will need more regular watering than those growing in the ground.

Watering & Feeding

Onions have shallow roots, so don't let them become short of water while the bulbs are actively developing. Water during prolonged dry spells, giving the soil a thorough soak rather than frequent light watering.

Don't automatically stop watering as soon as the first tops begin to droop. If the bulbs are still actively swelling and the soil is dry, continuing to water for a little longer can help them fill out and produce plumper onions. Once the crop is reaching maturity and around half the tops have fallen naturally, stop watering so the bulbs can ripen and dry properly.

Well-prepared fertile soil should usually provide a good start. Avoid excessive nitrogen later in the season, as this can encourage leafy growth at the expense of good bulb development and ripening.

Keep Them Weed Free

Onions don't compete well with weeds, so keep the ground around them clear throughout the growing season. Weed by hand close to the plants or hoe carefully between the rows to avoid damaging the shallow roots and developing bulbs.

Protecting Newly Planted Sets

Birds can sometimes pull newly planted sets from the soil before they've rooted properly. Check them regularly and gently push any disturbed sets back into place. Fleece or suitable netting can be used temporarily until the sets are securely rooted.

Watch for Bolting

Although ‘Stuttgarter Riesen’ is known for being slow to bolt, changes in temperature and other growing stresses can still cause onions to produce a flower stem. Remove any flower stems as soon as they appear and use these onions first after harvesting, as bulbs from plants that have bolted won't store as well.

Good Companions

Onions are easy to fit into a mixed vegetable plot thanks to their upright growth. Grow them alongside crops such as beetroot, lettuce and other leafy salads, making sure neighbouring plants don't shade or crowd the developing bulbs.

Making the Most of Your Bed

Quick-growing crops such as radishes and salad leaves can be grown nearby and harvested while your onions are still developing. Just make sure the onions continue to receive plenty of light and aren't crowded as the bulbs swell.

Crop Rotation

Avoid growing onions where onions, garlic, leeks, shallots or other alliums have recently been grown. These crops can be affected by some of the same soil-borne pests and diseases, so rotate them around the vegetable plot rather than repeatedly using the same ground.

Planning Ahead

Once your ‘Stuttgarter Riesen’ onions have been lifted, you can use the cleared ground for fast-growing salads or other suitable late-sown crops, helping you make more use of the space after your onion harvest.

When to Harvest

‘Stuttgarter Riesen’ can be harvested from around July to September, depending on planting time and growing conditions. Yellowing and naturally toppling foliage is a sign that the bulbs are approaching maturity.

Don't Bend the Tops Over

There's no need to bend the foliage over by hand to encourage the bulbs to ripen. Let the leaves yellow and fall naturally, then harvest before the foliage has completely died back.

How to Harvest

Choose a dry day and carefully loosen the soil beneath each bulb with a garden fork. Lift the onions gently to avoid bruising or damaging them, as damaged bulbs are more likely to rot and should be used first.

Drying Your Onions

Spread freshly lifted onions out somewhere dry with plenty of air circulation, keeping the foliage attached while they cure. In suitable weather they can dry outdoors; if conditions are damp, move them into a greenhouse or well-ventilated shed. Wait until the necks and outer skins are thoroughly dry before preparing them for storage.

Storing Your Harvest

‘Stuttgarter Riesen’ has good keeping qualities, so it's worth curing your best bulbs thoroughly. Store only sound, fully dried onions somewhere cool, dry and well ventilated, using net bags, slatted trays or a similar arrangement that allows air to circulate.

Top Tip

Choose firm, well-ripened bulbs with properly dried necks for storage. Use any damaged, thick-necked or bolted onions first and check your stored crop regularly so you can remove any bulbs that begin to deteriorate.

Flavour

‘Stuttgarter Riesen’ has firm white flesh with a mild, pleasantly sweet flavour, making it a useful all-round onion to have in the kitchen.

Best Enjoyed

Slice the bulbs fresh into salads and sandwiches, soften them slowly as the base for soups, sauces and casseroles, or roast them alongside your Sunday dinner. Their balanced flavour makes them an easy onion to use every day.

Fresh from the Plot

You don't have to wait until every bulb reaches full size. Lift a few earlier in the season to enjoy fresh, then leave the rest to mature fully if you want onions for storing.

From Plot to Store

Enjoy freshly harvested ‘Stuttgarter Riesen’ through summer, then cure your best mature bulbs thoroughly and put them into store. It's a simple way to make your homegrown crop last beyond the main harvest.

Top Tip

Use smaller or damaged onions first and save your firmest, best-ripened bulbs for storage. That way you'll get the most from your crop and reduce the chance of a damaged onion spoiling those around it.

What to Expect When They Arrive
Your onions are supplied as dormant sets in a netted bag, ready for planting. Sets are sold by weight, so the number of individual bulbs you receive may vary slightly from the approximate count shown on our website.

Ready to Plant
Your onion sets can be planted out as soon as they arrive. Each small bulb will establish roots and grow on to produce a mature onion ready for harvesting.

If You Can't Plant Straight Away
Remove the sets from their delivery packaging and keep them in their netted bag somewhere cool, dry and well ventilated until you're ready to plant. Check them occasionally and plant as soon as conditions allow.