James Martin's

Guide to Garlic

James Martin

How to Grow Onions, Shallots & Garlic

How to Plant Garlic Sets (The Simple Way That Works)

If you’ve never grown garlic before, trust me this is one of the easiest wins on the plot.

 

Plant it once, give it a bit of love, and months later you’re pulling up proper chunky bulbs that taste miles better than anything from the supermarket. I plant garlic every year at the allotment, and it’s one crop that rarely lets you down.

 

Here’s exactly how I do it..

 

 

 

When to Plant Garlic Sets (UK)

 

In the UK, you’ve got two good windows:

 

Autumn (October–December) – my favourite for bigger bulbs

Early spring (February–March) – perfect if you missed autumn

Personally, I always try to get mine in during autumn.

 

The winter cold helps the cloves split properly and you usually end up with much better bulbs.

 

Pick the Right Spot

Garlic thrives in simple, well-balanced conditions:

  • Plenty of sunlight
  • Free-draining soil
  • A sheltered spot, not overly exposed

If your soil tends to hold water during winter, it’s best not to push it garlic does poorly in wet conditions. In areas with heavy clay soil, raised beds or containers are a much more reliable option.

 

From experience, planting garlic in the sunniest bed available makes a noticeable difference it’s always worth it.

Prepare the Soil Properly

This is where the real magic begins.

Before planting, I always:

  • Remove any weeds
  • Loosen the soil to about a spade’s depth
  • Mix in well-rotted compost
  • Rake the surface level

One important thing to avoid is fresh manure it encourages leafy growth rather than developing strong, healthy bulbs.

Step-by-Step: Planting Garlic Sets

 

Keep it simple no need to overthink it.

 

1. Split the bulb
Break into individual cloves just before planting. Leave the skins on and choose the largest cloves for best results.

2. Plant the right way up
Place each clove with the pointed end up and the flat root down it makes a difference.

 

3. Space them out

  • Depth: 2.5–5 cm
  • Between cloves: 10–15 cm
  • Between rows: 25–30 cm

A little extra space helps produce bigger bulbs.

 

4. Finish up
Firm the soil gently and water if it’s dry then let nature take over.

How to Prevent Onions Bolting

One of the most common questions about growing onions from sets is how to stop them bolting. 

Bolting (flowering too early) is usually triggered by stress especially cold snaps after growth has started or drought later in the season. 

Here’s how I reduce the risk of onions bolting: 

 

1. Start in Trays Stable early growth reduces transplant shock. 

2. Avoid Early Planting in Freezing Soil 

Cold soil followed by warmth is a common trigger. 

3. Don’t Overfeed Nitrogen 

Too much leafy growth early on can destabilise the plant. 

4. Keep Growth Consistent 

 

Water regularly during dry spells to prevent stress. 

If an onion does bolt, remove the flower stem immediately but use that bulb first, as it won’t store well. 

 

When to Harvest Onions and Shallots You’ll know they’re ready when: 

  • The foliage turns yellow 

  • The tops naturally flop over 

Don’t bend them over artificially let them collapse on their own. 

Lifting and Drying 

  • Lift on a dry day 

  • Shake off excess soil 

  • Lay them out somewhere warm and airy 

I dry mine in the greenhouse, on racks in the shed, or outside in sunshine (if the forecast is reliable). 

Allow 2–3 weeks for proper drying, until: 

  • Skins are papery 

  • Necks are fully sealed

     

    How to Store Homegrown Onions and Shallots 

     

    Once fully dry, you can store them in: 

    • Onion strings 

    • Slatted crates 

    Keep them somewhere cool, dry and well ventilated. 

    Stored correctly, homegrown onions and shallots will last for months well into winter.

     


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