Why Your Garlic Didn't Form Bulbs (or Grew Small) and How to Fix It
, by Earthwise Garlic, 3 min reading time
Garlic that formed rounds instead of cloves, or came out small? Learn the most common causes and exactly how to fix them for next season.
Garlic is usually easy to grow, but when it doesn't form proper bulbs, or comes out undersized, it's frustrating. The good news is that poor bulb formation almost always comes down to a handful of fixable factors. Here's what causes it and what to do differently next season.
Not Enough Cold (The Most Common Cause)
Garlic needs a cold period to divide into cloves. This process is called vernalization. Without it, garlic often stays as a single round bulb rather than forming the segmented head you're expecting.
This is especially common in southern climates, mild winters, or when garlic is planted in fall when the soil is still too warm. In warmer regions (zones 8b and above), garlic often doesn't get enough natural cold to trigger proper bulb formation. The fix is to refrigerate seed garlic for 6 to 8 weeks at 35 to 40 degrees before planting, which simulates the cold period the soil isn't providing.
Softneck varieties also tend to handle mild winters better than hardnecks, which have a higher vernalization requirement. If you're in a warm climate and hardnecks aren't forming well, switching to an artichoke softneck like Inchelium Red is worth trying.
Planting at the Wrong Time
Garlic needs to establish roots before winter while not pushing too much top growth before the cold sets in. Planted too late, roots don't develop enough and bulb size suffers. Planted too early in warm soil, the timing gets out of sync with the cold exposure needed for proper development.
For most of the U.S., fall planting (October to November) hits the right window. In the Pacific Northwest, late October to mid-November works well. Read your specific zone and adjust accordingly.
Inconsistent Watering in Spring
Most of your bulb size is determined during spring growth. If garlic runs dry during April, May, and into June while it's building the bulb underground, you'll see it at harvest. Inconsistent watering during this window is one of the most common reasons for small bulbs in gardens that otherwise get everything else right.
Aim for about 1 inch of water per week during active spring growth, from rain and irrigation combined. Stop watering 2 to 3 weeks before harvest to allow the wrappers to tighten.
Planting Small Cloves
Each clove becomes one plant, and the size of the clove sets the ceiling for what that plant can produce. Small cloves make small plants and small bulbs. Always plant the largest cloves from each bulb and set the small inner cloves aside for the kitchen. Avoid soft, damaged, or unusually light cloves.
Too Much Competition
Garlic doesn't compete well with weeds. If weeds establish during the critical spring growth period, they pull water, nutrients, and space away from the garlic. Bulb size suffers. Mulch after planting and stay on top of any weeds that push through, especially in April and May.
Spacing also matters. Garlic planted tighter than 6 inches apart will reliably produce smaller bulbs. Give each plant room.
What About Rounds?
If your garlic produced single round bulbs with no cloves, that's a vernalization issue rather than a growing failure. Rounds are edible and taste like garlic. Plant them again next season with proper chilling beforehand and they'll often produce full bulbs. They're not wasted.
Starting with quality, properly selected seed garlic also helps. Seed that's been grown, cured, and selected for replanting performs better than garlic that wasn't chosen with planting in mind. Our seed garlic ships in September, ready for fall planting.