Why Your Garlic is Always Too Small (and What To Do About It)

If your garlic lets you down with small bulbs at harvest time, chances are you’re making at least one of seven surprisingly common mistakes. Most of them occur months before you’ll ever see the end result, so how do we avoid making them in the first place?

The Bulb Size Timeline

The thing about garlic is that the bulb you dig up isn’t formed in a sudden burst in early summer. That’s when we see the bulbs swelling for sure, but a bulb is built up in stages, stretching all the way back to the clove you’re about to plant.

From planting cloves, to developing roots underground, to getting enough chill time, to spring leaves, to the bulb itself dividing into cloves, to it swelling up, and on to harvest: upset things anywhere along that timeline, and it will come back to haunt you with a disappointing harvest.

Mistake 1: Planting Small Cloves

Mistake number one happens before a single clove even touches the ground! It’s tempting to just crack open a bulb and plant whatever you’ve got, but research on clove size keeps finding the same pattern: plant a small clove and you can expect to get a small bulb. Plant a big, plump one and you’re giving your garlic crop the best possible start and the prospect of bigger bulbs later on, because that big clove will have more energy and resources to draw on.

Break open the bulb of garlic and sort cloves into the biggest, fattest ones, destined for planting, and anything small, soft or in any way damaged set aside for immediate use in the kitchen. It sounds almost too simple doesn’t it? But it’s one of the single biggest influences you have over final bulb size.

Make sure you have picked the right type of garlic for your climate too: softneck garlic like California Early, Germidour or Picardy Wight tends to produce bulbs well-packed with smaller cloves that store for many months, while hardnecks such as Carcassonne Wight, Chesnok Red and Music are hardier – great for colder climates – have a stronger flavour, and produce a bonus crop of hooked or spiralling flower heads called ‘scapes’. They don’t store for quite as long, but will still keep for at least four to six months.

Give your garlic a leg up by properly preparing the ground ahead of planting. Garlic likes a sunny spot, and to prepare the soil first remove any weeds then simply spread out some well-rotted organic matter - for instance an inch (2-3 cm) or so thick layer of lovely garden compost - across the surface.

Mistake 2: Planting at the Wrong Time

Timing is everything. Garlic needs a decent stretch of cold to trigger the bulb into dividing up into several cloves. Without that cold spell, it will stay as a single, undivided lump known as a garlic ‘round’. This chilling process is called vernalisation.

Most garlic needs around seven to eight weeks below about 45°F (7°C) to get that chilling properly baked (or frozen!) in. Plant too late and your cloves may not clock up enough time in the cold before growth needs to get going; plant too early, though, and you risk soft, lush top growth getting caught out by a hard freeze.

The sweet spot is roughly three weeks after your average first frost date – still early enough for roots to establish, but late enough so that leafy growth doesn’t get away from you before winter properly sets in. I’m in the equivalent of zone 8, so planting garlic in mid to late autumn is just perfect, but do check out the timings above for where you are. And you could, of course, use our Garden Planner, which will give you more precise planting dates based on your location.

If you live somewhere that’s simply too warm to get a natural chill – say, zone 10 and up – just pop your cloves into a paper bag in the fridge for those crucial seven to eight weeks instead. It’s a bit of a cheat but, do you know what? It works, tricking the cloves into thinking they’ve had a proper winter! Of you may be able to find spring-planting garlic that’s been cold stored for you, so it’s ready to plant when you buy it.

Similarly, if you’re in really, really cold climates where the ground freezes solid early on and it’s just too cold for garlic, then you may also find that spring-planting garlic is the way to go.

Mistake 3: Planting Too Shallow

Mistake three is not planting cloves deep enough. It’s an easy one to make because a shallow-planted clove will still grow, it just won’t grow as big. I like to aim for a hole 2-3 in (8-10 cm) deep, which ends up with each clove having about an inch or a couple of centimetres of soil above its tip. If you have a lighter soil then you could go a bit deeper than this.

At the right depth, your cloves are properly insulated against hard frosts while that vulnerable rooting stage is happening underground over the winter. Plant too shallow and the cold could check growth or, in very cold climates, kill off the clove entirely. Too deep, though, and the emerging shoot has to fight harder to reach daylight, burning up valuable energy in spring that should be saved for building the bulb up later on.

Mistake 4: Growing in Soggy Soil

Mistake four catches out a lot of us, especially those gardening on heavy clay. Garlic is pretty hardy, and it will shrug off a proper cold snap, but it absolutely hates sitting in waterlogged soil, especially through the depths of winter when it’s least able to fight back. Roots sitting in cold, airless, saturated ground are prone to rotting before they’ve even had the chance to get established.

If your ground stays soggy over winter, growing in raised beds or deep pots are the fix, because well-drained soil keeps those roots breathing even when the rain won’t stop.

Mistake 5: Letting Weeds Get Out of Hand

Fast forward to spring, and this is where mistake five often sneaks in. Garlic has thin, strappy leaves which, paired with its shallow roots, make it a poor competitor against vigorous spring weeds fighting for the same light, water and nutrients.

Every bit of energy your garlic spends elbowing out a weed is energy it isn’t spending growing leaves, and more leaf area early on means more opportunity to capture the sun’s energy, powering up plants for building bulbs later on. But, crucially don’t use a hoe to clear around the bulbs. Instead, get in there and hand-weed regularly through spring, because garlic's shallow roots don’t take kindly to a hoe getting too close.

A simple mulch of something like grass clippings can help to then suppress further weeds and keep everything ticking along nicely.

Mistake 6: Letting Watering Slip

Mistake six is all about consistency, and right at the stage when it matters most. Once the bulb has formed and starts to swell is when your garlic is thirstiest, and letting plants dry out, even briefly, can stall that swelling exactly when you want it in full gusto. Keep the soil evenly moist – never waterlogged – right through this stage. This is the time when watering really matters, with warmer temperatures and long, sunny days drying out soil quickly, all while plants are growing at full tilt.

Then, once you spot the first lower leaves starting to yellow, it’s time to ease right off. Too much water this late can actually reduce the storage life of the bulbs and invite rot, right at the finish line.

Mistake 7: Harvesting Too Late

It’s tempting to leave garlic in the ground that little bit longer hoping for extra size, but once too many leaves have died back the bulb actually starts to deteriorate underground. The outer skin splits, the cloves separate, and the whole thing loses its keeping quality.

So, watch for the lower third to a half of the leaves turning yellow and papery, then get your fork in there and lift them up.

I like to shake off any excess soil from the roots and then, without trimming or in any other way interfering with the lifted garlic, move it somewhere warm and dry to finish curing, ready to store somewhere dry and out of direct sunlight.

So there you have it: seven easy-to-avoid mistakes. Plant big cloves, get the depth and timing right, drainage sorted, the weeds out, water steadily, and harvest right on cue, and you’re assured of a garlic harvest to be proud of!

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