Herne Bay Allotments and Gardens Association












Onion Garlic and Shallot Sets

After unpacking new purchases, prior to planting, put them into a cool, light, well-ventilated and frost free place, away from direct sunlight.

Winter hardy varieties can be planted in early autumn, otherwise plant between February and April, as soon as the soil is sufficiently dry and warm; in practice this is usually late winter or early spring for sandy soils, and mid-spring for clay-based soils. Heat-treated onion sets (which have had their flowering potential suppressed, so are bolt resistant) should not be planted before late March or April.

Prepare the soil by digging over and incorporating some fertilizer, work the soil down to a fine tilth as if preparing a seed bed.

Onion and shallot sets are planted into a shallow drill (groove) in the soil about the same depth as the set, or a bit less for some of the longer sets (many shallots, for example). Alternatively plant them individually with a small trowel. It’s not advisable to just push them into the ground as this may cause damage.

Remove any loose papery skins before planting the sets. Spacing can be anything from around 10cm (4in) apart for onions and around 25cm (10in) for shallots, depending on the size of bulbs. Closer spacing results in large numbers of small bulbs, whereas wider spacing results in a smaller number of large bulbs.

When they are planted, the tips at least should still be protruding from the soil surface.

The ‘Dave’ approach is to start sets off in modules and then plant out when conditions are right. This bypasses bad weather problems, allows sifting out of the occasional dud and avoids the annoyance of finding your sets pulled out of the ground by mischievous birds.

In the spring there is rarely the need to water newly planted sets. But in dry spells later on in the summer and autumn, new plantings of overwintering onion sets should be watered in after planting.

Keep weeds checked as dense weed growth will seriously affect yield. Water if the weather is dry (not otherwise) and feed occasionally. Feed an autumn-sown crop with a liquid fertilizer in March.

Onions form a bulb when the temperature and the number of daylight hours hit the right combination for them which triggers their clock. Until that happens, onions use the daylight to produce a good deal of top growth before they form bulbs (and the more top growth, the bigger the bulb). When the daylight reaches the right number of hours for that variety of onion, the onion will stop forming top growth, and form a bulb instead. The size of the bulb that eventually forms depends on the size of the "stalks", and the number of them. There will be 1 ring in the onion for every stalk that formed, and the larger the stalk, the larger each ring will be. Bulb formation will pause though during dry, very hot or very cold weather.

Remove any flower stems which appear. Mulching is useful for cutting down watering and for suppressing weeds. Stop watering once the onions have swollen and pull back the covering earth or mulch to expose the bulb surface to the sun.

When the bulb is mature the foliage turns yellow and topples over. Leave them for two weeks and then carefully lift with a fork on a dry day.

Onions which are not for immediate use must be dried. Spread out the bulbs on sacking or in trays; outdoors if the weather is warm and sunny or indoors if the weather is wet. Drying will take 7 to 21 days, depending on the size of the bulbs and air temperature. Inspect the bulbs carefully: all soft, spotted and thick-necked onions should be set aside for kitchen use or freezing. The rest can be stored.

Store in trays, net bags etc; anything where the air can circulate. Choose a cool and well-lit place to store them where they will keep until late spring.

If you have any comments on these notes or alternative advice then please let us know.




Position: full sun                        Soil: any soil

Rate of growth: average            Hardiness: fully hardy

A mid-late maturing variety with flattish-round bulbs of a beautiful dark red colour. An excellent cropper producing attractive, firm well flavoured bulbs which keep well. An attractive addition in the salad bowl.

Garden care: Plant onion sets so that the tips are just showing, and then firm the soil around them from mid-February to March, 15cm (6in) apart in rows 30cm (12in) apart. Lift the onions when they are mature (normally in August) and allow them to dry before using.

Position: full sun                    Soil: any soil

Rate of growth: average          Hardiness: fully hardy

Onion sets are the easiest way to grow onions in the garden. Planted in March or April, they will mature faster than onions grown from seed. 'Sturon' is a flavourful variety which produces round, straw-coloured onions that mature in August.

Garden care: Plant onion sets so that the tips are just showing and firm the soil around them from mid-March to mid-April, 15cm (6in) apart in rows 30cm (12in) apart. Lift the onions when they are mature and allow them to dry before using. Store the fully ripened, sound bulbs in nets or trays and you can use them throughout the autumn and winter.

Position: full sun               Soil: any soil

Rate of growth: average     Hardiness: fully hardy

Sets are the easiest way to grow shallots in the garden. Planted very early in the season, in mid-February if possible, they mature faster than those grown from seed. 'Golden Gourmet' is a very high yielding, Dutch variety that can be harvested as early as July. It has a golden brown skin, stores well and has better resistance to bolting than many other varieties.

Garden care: Plant onion sets from mid-February to March, 23cm (9in) apart in rows 30cm (12in) apart. These onions will fan out to produce a cluster of 5, 7 or 9 bulbs so give them at least 9in of space between the sets. Leave the upper third of the bulb showing as shallots are more prone to rotting in damp soil. On average shallots take approx 26 weeks to mature. Lift the onions when they are mature and allow them to dry before using.

In autumn we have Shakespeare and North Holland Blood Red onions and Jermor shallots.

North Holland Blood Red can be grown to a full size onion or harvested when young as a salad onion.

Shakespeare British bred variety produces high yields of tasty, good sized bulbs which are darker brown-skinned than most varieties once dried off. Shakespeare has excellent skin formation that means it shows good storage potential.

Jermor is a banana shallot has a superb, slightly sweet flavour and stores well. It’s well known for being one of the best, most reliable autumn-planting shallots you can grow.




The Shop stocks a few varieties of sets - some for spring planting and some for autumn planting (over-winter types). You may prefer to order other varieties from our suppliers - more options but at a higher price. For spring planting you may prefer to order heat-treated sets which give higher yields and reduce the risk of bolting (producing seed heads); these will arrive much later as the treatment takes time. We do not stock heat-treated sets.

Spring planting sets arrive early in the year (usually January) while the autumn ones arrive around September time. In spring we have Sturon and Red Baron onions and Golden Gourmet shallots. In autumn we have Shakespeare and North Holland Blood Red onions and Jermor shallots.


                               Lautrec Wight - hardneck - originating in SW France - white-skinned, deep pink cloves

                               Carcassonne Wight - hardneck - originating in SW France - exceptional - pink cloves - vigorous in UK climate

                               Early Purple Wight - softneck - robust early variety (perhaps from mid-May). Use within 3 months of harvest.

                              Elephant Garlic - not a true garlic - closer to a leek. Produces very large bulbs with mild garlic flavour. Each individual clove is close to the size of some whole real garlic bulbs.


GARLIC - softneck

Softneck garlic generally produces smaller, more tightly-packet cloves:

Does not produce flower stalks unless stressed

It is best harvested when the foliage starts going over

It has better storage qualities than hardneck varieties

If autumn planted it will keep until mid- to late-winter

If planted in early spring it can be stored until next spring

GARLIC - hardneck

Hardneck garlic originates from climates with colder winters:

Flower stalks appear readily

Fewer, larger cloves covered with a looser tunic are produced

It is considered to have stronger and more interesting flavour

It is best gathered when the foliage has changed colour

It stores only until mid-winter