Allium vegetables
These nutrient packed, vampire repellent, pungent plants form the base of many dishes around the world. Alliums include onions, leeks, garlic, chives and shallots. Fun fact: the word Allium is ancient Greek for Garlic (Allium sativum - cultivated garlic).
Alliums can store well, to do this brush the mud off and dry on a shelf or rack. Once dry keep them in a dark, cool, dry place much like spuds and they can store up to a few months. All the below can be susceptible to rust, which is a disease that affects these plants in the leaf tissues and can cause stunted bulbs so it's worth keeping an eye out for this and removing an affected plant to reduce spread. Alliums do well after potatoes or brassicas when using crop rotation as they prefer poorer soil than some other plants.
For companion planting they have a beneficial affect on brassicas and root veg, deterring pests that affect those crops. Chives and wild garlic could well sit in this category or within herbs. Wild garlic is also a medicinal plant and can potentially indicate a long standing woodland area.
Onions
First up are the more well-known onions, coming in white, brown and red. Onions can be grown from seed or sets (small bulbs you can buy in many shops). There are two types of onions, autumn sowing varieties such as Autumn champion, which has a great cold tolerance and spring sowing such as Red Baron. They typically take around 3 months from sowing to harvest in the UK (80-100 days) depending on your USDA range - check our page on that. If you're looking for something new try Mammoth Onions (white or red), which can grow up to 30 cm (1 ft) diameter.
For spring sowing, start them off from early March, or plant out autumn varieties from September in batches to ensure you have a good supply. Place seeds 1 cm apart (approx 1/3 inch) and thin out once they start to grow. You can sow sets, 10-15 cm (4-6 inches) apart in to a sunny spot.
To give the seeds the best start mix in a few centimeters (approx. 2 inches) of compost to your growing medium. Onions can also be used in square foot or companion planting - see our page for more info. Onions can manage in a range of soils from less rich following potatoes to nitrogen rich soil, for example following peas or beans, which can fix nitrogen into the soil. As they're quite veritable it allows you flexibility in crop rotation.
Spring onions (Scallions)
These plants require very little room so could be incorporated with other plants or flowers if space is tight, which also makes them great in square foot or companion planting filling those small spaces. Sow seeds from March on wards, or earlier if you have a warmer climate, direct approx 5 cm (2 inches) apart in soil that is not too nutrient rich. Some varieties such as White Lisbon may be able to grow for the majority of the year in the UK and warmer climates.
Crop rotate as above or if you are using companion or square foot planting, pair with plants that do not fix nutrients such as legumes. If you have very rich soil/compost you might find they grow a lot of top leaves rather than focus on the root and stem. If you do scatter seeds, just thin them out later as they grow through. White Lisbon and Blood Red Holland are easy to grow varieties. Welsh onions can also be treated in a similar way.
Garlic
There's a few varieties to try ranging from regular cultivated, wild (which is not actually garlic or even an allium but it is treat as such due to its strong garlic flavour so its included here), black and elephant garlic, although much bigger it has a milder flavour. These usually require a longer growing season and can be planted Nov-Dec or in March for spring varieties so check the label before you buy. You should be able to start harvesting from July throughout the summer.
Garlic needs to be well drained as it struggles in boggy conditions and ideally pop it in a sunny site. Plant cloves 2 -3 cm (1 inch) below the soil no closer than 15 cm (6 inches) apart. If you intend to grow it in rows, make sure you keep at around 30 cm (1 ft) between rows.
The garlic you buy in a grocers or a supermarket is likely to be a higher yielding soft neck variety. Hard neck types produce less cloves but can tolerate colder temperatures, however hard necks can take up too will take a year to 2 to get started.
Leeks
Sow leeks under cover off from seed in march and April. Like chives, you can plant leeks out from April to June individually or plants grown together from seed (clumps). For a clump try 2-5 plants, over 5 will compromise the plants. Hardy varieties like Musselburgh will be able to grow throughout more of the year.
If you want a bigger, bushier leek rather than a narrow one try planting them individually 20 cm deep and filling the hole with soil and water. This method is called 'puddling' and with the majority of the stem underground the plant will grow stronger. If growing leeks in rows, leave around 30 cm (1 ft) between rows. I prefer clumping, which provides thinner 'younger' leeks I can use in stir frys and modern takes on dishes. To do this, so 3-4 seeds together and plant the group no more than 10 cm (4 inches) deep and when you harvest you will need to harvest the whole clump together.
Leeks have their own flavour, different to onions and garlic. If they are not for you you can use it to tell people they've got "a leek on their radiator", or fridge, roof. You get the idea.
Image credit: Heather Gill
Shallots
Image credit: Sorin Gheorghita Unsplash
Image credit: Barbara Ciliers Unsplash
If you don't like the strong flavour of onions but want a base to your dishes, shallots could be for you! Thinner than typical onions with a milder flavour, shallots are easy to grow. They are typically sown in sets or rows but you can incorporate them into square foot or companion planting. If you are growing shallots together, sow around 20 cm (8 inches) apart and allow around 30 cm (1 ft) between rows. Alternatively have a look at companion or square foot methods if this is your preference.
You need to check on shallots as they like moist soil/compost but it needs to have good drainage. For info on soil types and how to work with them see our articles or videos.
Sow seeds or sets from late autumn to spring and harvest in summer (July-August). They should be ready to harvest when their leaves/top foliage dies off and drops. Shallots do well in nitrogen rich soil.