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GROW GUIDE - ONIONS, SHALLOTS & GARLIC

Updated: Mar 16, 2022

ONIONS

Onions, shallots, and garlic are a kitchen favourite, wildly versatile and used in many foods - you'll be surprised by just how many varieties there are. We recommend trying to grow onions at least once as they are very easy to grow, and as an added bonus, they often keep weeds at bay!


Onions can be planted either from seed (very economical) or from onion 'sets', which are bulbs that are not allowed to grow to their full size, which grow faster and into larger bulbs.


OVERWINTERING

Although many onions are grown in the spring, by overwintering onions you can often achieve earlier crops (up to a month before those sown in spring) that have had longer to mature and a slower growth, meaning an increase in flavour. These are best sown from September to October as this gives them time to develop roots before the cold slows growth (although it is possible to grow them any time, as long the ground is not frozen).


SPRING SOWN ONIONS

The key to growing onions is to have a well drained, but firm, soil. To achieve this it is best to add organic matter in the form of well rotted manure or a peat compost. By digging this into the ground you will increase the drainage in a clay soil, and increase the substance of a sandy soil. Save some manure for mulching after the onions have been planted, and be sure not to use fresh manure as this may lead to rot. If you have a sandy or light soil, rake it through, then tread on it to firm it up.


HOW TO GROW

Onions are very simple to plant, all you need is; a weed free bed, well drained soil, and sun! In March/April push the onion sets into the ground with a 10cm distance (30 cm between rows). Onions can be grown in small amounts in troughs or tubs but should never be grown in growbags. After the bulbs have been planted, weed and mulch with any remaining manure. Keeping the ground clear of weeds is vital as onions are very poor competitors and other plants encroaching on them will drastically reduce bulb size.

Water onions if the weather is dry, but be aware it is easy to over water them. A small sprinkle is better than a deluge, and any mulch will help maintain the moisture below the surface. Try giving a feed of liquid fertilizer (liquid Growmore, or a specific vegetable feed is best). Any onion flower stalks should be immediately removed as they cause the bulb to warp and reduce in size.

Tip: If you have trouble with birds attacking onion sets then try taking the top dead leaves off the bulbs, sometimes birds mistake the tips for worms!


HOW TO HARVEST

Tip: Try applying potash around and on the bulb three weeks before harvesting, this toughens the outer layer of skin meaning it is less prone to bruising and damage when harvested.

Onions should be harvested when approximately half the row's leaves turn yellow and collapse or individually if the leaves are 75% yellow (if you are worried about rot then harvest them when the leaves are only 50% yellow), however if rain is due it is a good idea to harvest all mature plants as moisture can lead to rot. To do this feel the neck above the bulb for a 'soft spot' this is a sign that the bulb itself has stopped growing and can be harvested. At this point the bulbs will be soft and tender so great care should be taken not to bruise or damage them, gently loosen the soil around them and lift with the leaves of the plant. After shaking off any large clods of earth and any rotten leaves then air dry the bulbs for a few days. By applying a dose of sulphate of potash to the bulbs as the leaves yellow you can harden the skins and this helps reduce the loss from damaged bulbs.

After the bulbs have hardened it is time to cure them, gently clean the onions but leave as many of the outer scales intact as possible, then leave them to dry, ideally outside under cover (They may have a strong onion smell) or in bad weather inside with 30cm of the green growth left. After 2-3 weeks the bulb will be ready for its second cleaning, trim the roots off and green growth down to 2" and wipe any soil off, by then the plants will be hardened enough physical damage is unlikely.

After another week the onions will be ready for use and storage, Onions that do not keep well should be kept in the fridge however other onions may be kept in any dry cool place (ideally with airy space so they do not sweat.)

ONIONS

DESCRIPTION

Centurion F1

​The centurion F1 Hybrid is notable for its rapid maturation, the onions are large globe shaped and quite suited to the UK fickle weather. These have a good flavour and are ideal for beginners or those with little time. The fast rate of growth minimise weed competition problems.

Hercules F1

Hercules is one of the few onions to have the award of garden merit from the RHS and it has certainly earned it. The onion it produces slightly flat well flavoured reliable onions which have a gold-brown skin, store well and are extremely bolt resistant.

Picko Bellow

Picko Bello is an improved Dutch Sturton cultivar that is very high yielding. It stores very well and is a early cropper and bolt resistant.

Sturton

Sturton is an early main crop which produces medium onions that has proved very popular in recent years. It has a good taste and like most modern varieties is quite bolt resistant.

Stuttgart Giant

Stuttgart Giant lives up to his name. It is very productive cultivar with a mild taste. Ideal for adding some light flavour to meals. It stores well and is well known amongst gardeners.

Red Barron

Red Barron has the Award of Garden Merit and is considered one of the best red onions. Ideal as a salad onion to add colour to a meal. They have a mild taste with fantastic colour and very reliable.

SHALLOTS

What are Shallots?


Shallots are a distinct botanical variety of onions which rather than producing a single large bulb, produce numerous smaller ones. They have a very distinct mellow taste (often slightly garlicky) and are considered superb for pickling with a stronger taste than standard onions and an increased firmness. Shallots are ideal for meals where smaller amounts of onion are called for (as opposed to using 1/4 a bulb) and where useing garilc may not be ideal. In addition they mature faster than onions (although they do not keep as well) and importantly they produce no irritant compounds making cooking with them far easier! Shallots can be grown from seed (which whilst being economical takes longer and produces fewer bulbs) and sets which can produce 12 or more large bulbs, whilst maturing faster.


HOW TO PREPARE

Shallots, being Alliums like onions require the same preparation, They benefit from organic matter being added to the soil to increase drainage whilst requiring sun to achieve the full effect. They are again quite suitable for the organic no dig method however fresh manure as always should be avoided.


HOW TO GROW

Shallots have a tendency to splay everywhere when mature so it is always advised to plant them further apart than base onions (25cm apart with 40cm between rows), otherwise they are very similar to onions in that they should be pushed into the soil and left with the tip above ground (unlike with onions do not remove the tip). As the shallots grow it is important to reduce weeds in the bed as although they are more competitive than onions, any local weeds will still reduce the output of the bulb. Using a mulch of manure or black membrane will reduce weeds and retain moisture making them easier to maintain.


HOW TO HARVEST

Shallots unlike onions have a tendency to fall when mature as they develop into a 'nest' of bulbs which means you should harvest individually rather than an entire row as you would onions. Gently lift them by first loosening the soil around them with a garden fork and take large clumps of earth off them but then leave them allowing them to dry as after harvest the skin and interior scales will be soft and easily damaged. By applying sulphate of potash to the bulbs a few days before harvest then the bulbs can be hardened and reduce this problem.

After drying for a few days (if weather is damp then this can be done indoors) then take them inside the house in the warm, gently wipe the worst of the dirt off and trim the leaves down to 15cm. After curing them for 1-2 weeks you can then separate them, gently clean them, trim the roots and take the green growth down to 1". After a further 1 week then take the leaves off entirely and they are ready to be stored. they store well and can often be kept for over 6 months!


SHALLOTS

DESCRIPTION

Red Sun

Red Sun has an attractive red skin and is believed by many to be the best red shallot, it is worth noting it has white flesh not red.

Biztro

Biztro is a fantastically tasty pale red shallot, it is often labelled as a premium shallot, it grows rapidly, resists bolting and produces an even crop.

Yellow Moon

Yellow Moon can be grown either in the Autumn or Spring, it has a low bolting risk , well flavoured and popular.

Golden Gourmet

Golden Gourmet is a traditional flavoured shallots, it is very versatile and well suited to a number of jobs. It has earned the award of garden merit and has a fantastic yield.

Picasso

Picasso has a shiny light-red skin with a mild taste and good crunch. Excellent for pickling.

GARLIC

Different types of Garlic


Garlic is, like onions and shallots an edible Allium, formed of numerous cloves inside each head it can be very productive and it is easy to grow a whole year's supply at low cost. There are two main commercial forms of garlic: Softneck and Hardneck.

The softneck garlic is more suited to warm places with limited frost and a great deal is grown in Asia, especially china, it is the garlic normally seen in pictures braided for storage and is the more productive of the two forms, It is more suited to spring planting and storage than hardneck garlic.

Hardneck garlic on the other hand is incredibly cold tolerant having originated in the USSR before being brought over to America and subsequently the rest of the world. Hardneck garlic also produces flowering scapes which can be cut and used as a tasty spring green, it however has a relatively short storage life.

The very best garlic, regardless of form is often considered to be from the Isle of Wight and these are renowned around the world (any cultivar with Wight in the name), French garlic however comes up a close second and is the most common variety found for planting in shops.

Other more niche garlic includes Elephant garlic (actually not a garlic but a close relative of leek) which produces a milder large bulb and wild garlic, delicately flavoured (and sometimes an invasive weed). Unfortunately we do not have these in stock as there is always a limited interest but enthusiasts should definitely consider them.


HOW TO PREPARE

Garlic is like all of the Alliums in that it requires full sun and appreciates a well drained soil, it is also a hungry plant so with this in mind, when preparing a bed to plant it is worth digging manure in and feeding with a high nitrogen feed. It is important to have good drainage in the soil as garlic will fail utterly if waterlogged. Again use of the organic no dig method provides garlic with all its requirements and is highly recommended. In addition if your soil is acidic it is highly recommended to add lime as garlic struggles to grow below a pH of 6 (local Bristol gardens should be perfectly ok).

In a clay soil, to ensure good drainage it may be worth building raised rows (try to rake the soil rather than dig it or it will just compact and make things worse) meaning the clay has adequate run-off.


HOW TO GROW

Garlic is a crop which is best grown over the winter, if planted in late October/November then it produces a mass of roots throughout the winter and then bursts into growth in the spring. Ideally it would have a one month period of vernalisation where the temperature is kept below 10*c this increases flavour and bulb size. Garlic can be grown in the spring, generally results are considered to be inferior compared to autumn however it is still an efficient crop and there are some benefits to such a late planting such as producing Rounds.

If a garlic is not provided with enough cold then some of it may not fully develop instead producing immature bulbs rather than cloves, called rounds. These are perfectly edible however they have a mild taste, the better use is to cure and store them for planting next October, this leads to large highly productive garlic plants which are often used as show plants by professionals and is always worth doing.

The garlic plant itself needs very little care apart from weeding and should only be watered occasionally when dry, however a light mulch is always beneficial. The flower head are often taken off hardneck garlic as although the flowers are attractive they detract from the bulb and removing it can increase yield by up to 20-30%. In the case of hardneck garlic the scape can be harvested when it has curled and is about to grow upwards.


HOW TO HARVEST

As with other Alliums you can tell when garlic is ready to be harvested by the state of its leaves, when the leaves start to yellow the plant is withdrawing resources from the foliage and diverting all its energy to the bulb, At about 20% yellowing watering should be stopped immediately to prevent the bulb from waterlogging and to speed the bulb's drying. As this happens then an addition of potash will as with onions harden the skin of the bulbs and aid in harvesting.

At approximately 50% yellowing the bulbs can be lifted ready for drying (although many people may recommend allowing the entire foliage to wilt, this often splits the head as the garlic attempts to spread and this makes curing harder whilst reducing storage life! If you are uncertain it is always better to err on the side of caution. If you would prefer to naturalize garlic for use a a perennial then it is possible to leave some of the heads in the soil at which point they will die down and then come up again for next year.

Curing garlic is much quicker than curing of onions and shallots, indeed it is not even required as garlic tastes great fresh from the ground however it is beneficial in storage of the bulbs.

For softneck garlic the cloves should be loosely bound together in small bunches and then hung from their scape for 2-3 weeks. (this is when the garlic is traditionally braided as seen with traditional French garlic. After a week trim the foliage back to 3-4 inches and remove most of the roots before gently cleaning the dirt off. They are then ready for storage and should last about 6 months in a cool place.

Hardneck garlic however lacks the scape and therefore should be gently cleaned and placed side by side on newspaper in a warm room, rotating the bulbs every few days to keep the drying even. The outer protective scales should then harden and form the protective coating normally associated with a garlic head.After a week you can trim down the foliage and the roots as with softneck garlic and cleaning the dirt from the heads allows them to cure faster.


RE-PLANTING

As with shallots it is possible (although not always advised) to replant garlic cloves, The cloves replanted should be the best of the previous years as in that way you take the most productive and suitable cloves for your garlic (even though they are theoretically clones provenance is still a factor). After storing them it is ideal to soak the bulbs for 5 minuets in a fungicide and never plant any which either have no outer skin (this protects the clove from diseases and dictates when the roots appear) or have any brown spots indicating rot. Over time the vigor of such crops may decrease and it would be ideal to buy certified disease free stock to restore yields.


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