How to Refrigerate Seed Garlic Before Planting (and Why Vernalization Matters in Warm Climates)
, by Earthwise Garlic, 3 min reading time
Growing garlic in a warm climate? Learn why garlic needs cold to form bulbs and how to refrigerate seed garlic before planting to simulate winter.
For eating garlic, refrigeration is the wrong move. Store whole heads at room temperature in a cool, dry, well-ventilated spot. Cold and humidity cause cloves to sprout prematurely.
The exception is seed garlic in warm climates. If you're growing garlic in the southern United States where winters are mild, refrigerating your seed before planting may be the difference between full bulbs and disappointing rounds.
Why Garlic Needs Cold to Form Bulbs
Garlic evolved in regions with cold winters. Its growth cycle depends on a chilling phase that triggers internal signals telling the bulb that winter has arrived and passed. During cold exposure (roughly 32 to 45 degrees F), the plant undergoes biochemical changes that activate the genes responsible for clove formation. When temperatures rise in spring, the plant resumes growth and develops multiple cloves underground.
Without that cold exposure, garlic stays in its pre-winter stage. It will grow leaves and roots but remain as a single, undivided round rather than the segmented bulb you're expecting.
Why This Matters in Warm Southern Climates
In northern regions, the ground handles vernalization naturally. Garlic sits in cold soil through winter before resuming growth in spring. But in southern states like Texas, Louisiana, Florida, Alabama, and parts of southern California, the soil often stays too warm. Garlic planted directly in these climates may never get the chilling time it needs.
The fix is refrigerating your seed garlic before planting, simulating the winter the ground isn't providing.
How to Refrigerate Seed Garlic Before Planting
Keep bulbs whole and make sure they're clean and dry before refrigerating. Place them in a paper or mesh bag — something with airflow. Avoid sealed plastic bags, which trap moisture and can cause mold. Store in the refrigerator at around 35 to 40 degrees F, away from the crisper drawer where humidity tends to be higher.
Refrigerate for 6 to 8 weeks before your planned planting date. Keep garlic away from apples, bananas, and other ethylene-producing fruit, which can trigger premature sprouting.
A few days before planting, remove the garlic and let it come to room temperature. Then break bulbs into individual cloves and plant each one pointed side up, about 2 inches deep.
What Happens If You Skip It
If you plant garlic in warm soil without pre-chilling, it will still grow normally above ground. Underground, the bulb stays as one solid round instead of dividing into cloves. Those rounds are edible and taste like garlic, but they can't be divided for replanting. If you refrigerate those rounds properly before planting the following season, they'll often produce normal heads.
Tips for Southern Garlic Growers
Plant in late fall or early winter, typically November through January in most southern zones. Choose varieties suited to warm climates. Softneck types like Inchelium Red perform better in mild winters than most hardnecks, which have higher vernalization requirements. If you're in zone 8 or above and hardnecks aren't forming well, switching to a softneck is often the simplest fix.
In Oregon and the Pacific Northwest, this process isn't necessary. Our winters are cold enough that garlic planted in October or November receives its vernalization naturally in the ground. If you're not sure whether your climate needs pre-chilling, a good rule of thumb: if your ground doesn't freeze reliably each winter, it's worth refrigerating.
Have a question about growing garlic in your climate? Reach out anytime. Browse our seed garlic varieties for fall planting.