How to Grow Pre-rooted Onions and Garlic

Preparation, Planting and Growing 

 

What to expect when they arrive: We have hand planted these sets/cloves into the cells to start the growing process off. These are now all rooting nicely and many will have the green shoots emerging from the top of the set/cloves. Don’t worry if some aren’t showing yet, they will.  

As soon as you can, take them out of the packaging and give them a good water. If you can’t plant them straight away, put them in the garden somewhere out of direct sunlight and strong winds, keep them moist until they are ready to be planted. 

Ease each plug from the tray, being careful not to break too many roots, they will however re-produce a lot more roots once planted. 

 

Prepare your soil: Onions and garlic prefer an open, sunny site and light, free-draining soil. If you have heavy soil, dig a generous amount of grit and organic matter into the planting area to ensure better drainage. Avoid planting in very heavy or freshly manured soil. Onions are sensitive to acidity, so if you have acid soil add some Garden Lime to the area well before planting, or a Pre-planting Onion, Shallot and Garlic Fertiliser. 

 

Planting: Both autumn and spring varieties can be planted straight outside into prepared soil. Loosen the soil and dig in some Pre-planting Fertiliser for added nutrients. 

 

Onions: Plant onion with the tips of the sets showing at the soil surface, it’s the same level as the cell they have been grown in. Onions should be spaced 5-10cm (2-4in) apart with 25-30cm (10in to 1ft) between rows, and shallots 15-20cm (6-8in) with 30-45cm (1ft to 18in) between rows. 

 

Garlic: Garlic cloves should be planted so the tip of each clove is 2cm (1/2in) below the soil surface. We suggest leaving 15cm (6in) between individual cloves and 30cm (12in) between rows. 

 

Aftercare: During the growing season, water if the weather is dry and give an occasional feed with a general liquid fertiliser and keep the area weed free. Stop watering and feeding once the bulbs have swollen and remove any flower spikes when they appear.  

 

Did you know? Hard-neck garlic varieties may well produce a curly flower stem (commonly known as a scape), and cutting this off will increase the size of your bulbs. The scape has a fresh, garlicky flavour that is a delicacy - perfect for air frying, stir fries and adding flavour to your favourite dishes.  

 

Plant Care: 

Weeds can wreak havoc on crops, robbing essential nutrients and moisture from your plants. Keep on top of weeding using an onion hoe or hand weeding to avoid damaging your plants and bulbs.  

 

Harvesting, Storage, Pests & Disease 

 

Harvesting:  

 

Onions: These can be lifted as soon as they reach a useable size, use a fork to ease them out of the earth. If you’re harvesting for storage we recommend waiting until the foliage bends over and dies down naturally prior to lifting. 

 

Garlic: To lift, you should ease your bulbs out of the ground with a fork and allow them to dry outside (if the weather is fine) or in a well-ventilated greenhouse or shed until the skins have hardened. 

When harvesting garlic, we’ve found that a good indication is when their foliage starts to turn yellow and wither. 

 

Storing: Onions and garlic are ready for storage when the skins are completely dry and papery. They should be kept in a light, cool and well-ventilated place either plaited in bunches or stored in nets. After lifting garlic, dry off the bulbs in a light and airy space. They should ‘rustle’ when their outer skins are fully dry. We recommend storing in a cool, dry place until used in the kitchen. 

 

Here are some of the most common pests and diseases to look out for: 

 

Onions: These can be prone to fungus-borne diseases, so we recommend trying to rotate their growing position each year so you’re not planting in contaminated soil.  

 

Rust Disease: Rusty spots form on both sides of infected leaves and break open to release dusty, orange airborne spores. Severe attacks may cause the leaves to shrivel prematurely and will reduce vigour. Unfortunately, there is no solution or cure to rust disease. We recommend keeping a close eye out for the signs and removing and destroying any infected plants to help it spreading.  

 

Onion White Rot: The leaves will start to turn yellow and wilt, which prevents the bulbs from forming properly. A good way to tell if the bulbs have been infected is they will have white, fuzzy spots. We recommend watching out for rot and removing any infected bulbs from the area to prevent it spreading. 

 

Onion Fly: The leaves will start to wilt and turn yellow, preventing the bulbs from developing. Onion fly can affect garlic and leeks as well as onions. The larvae of onion fly live in the soil and eat the roots of the bulb, eventually burrowing into the bulb itself. Protect your crops with Insect Netting. However, if you do have issues with onion fly, we recommend simply discarding any bulbs. 

  

Onion Downy Mildew: The leaves will begin to turn yellow and die off from the tip downwards. In wet weather, white mould develops on dead parts often turning a darker colour later. Remove and destroy any affected bulbs.  

 

Onion Neck Rot: A fungal disease that can occur in storage. We’ve found that to avoid neck rot, you should water regularly and stop feeding in August, in addition to keeping crops dry after harvesting.