Garlic turning green happens when cold storage triggers an enzyme reaction inside your cloves. Temps below 50°F (10°C) wake up an enzyme that creates green and blue pigments in the flesh. This color change looks strange but it does not mean your garlic has gone bad at all.
Your green garlic safe to eat and tastes just fine in all your recipes at home. The color comes from harmless compounds that form when sulfur mixes with amino acids in the cloves. You can use those green tinged cloves the same way you would use any normal garlic in your cooking.
When I first found green garlic in my fridge after storing some bulbs in the crisper drawer for a few weeks, I got worried. The cloves had turned a pale blue green color that looked wrong to my eyes at the time. I almost threw them out before looking into what caused the change and finding out they were perfectly fine to use in my cooking.
The garlic greening causes come down to an enzyme with a long name you can skip learning. Research shows this enzyme wakes up when garlic sits in cold temps for too long. It breaks down certain compounds and creates new ones that show up as green or blue colors in your cloves.
Your refrigerator falls right in the danger zone for garlic greening to occur in your stored bulbs. The typical fridge runs between 35°F and 45°F (2°C to 7°C) which is cold enough to trigger the enzyme. Room temp storage keeps your garlic out of this problem zone and stops the color change.
I now keep my cured garlic in a wire basket on the kitchen counter where temps stay around 65°F to 70°F (18°C to 21°C) all year. The bulbs last for months this way without turning green or losing their flavor. This simple storage spot works better than the fridge for keeping garlic looking and tasting right.
You can prevent garlic from turning green by storing it at the right temps from the very start. Keep your bulbs at room temp or go all the way down to 30°F to 32°F (-1°C to 0°C) for true cold storage. The middle ground temps in a standard home fridge cause all the greening problems.
The good news is that garlic greening can reverse itself over time with better storage in your home. Move those green cloves to room temp and the color will fade back toward normal within a few weeks. The flavor stays the same through the whole process so you lose nothing by waiting it out a bit.
In my experience, cooking with green garlic works just as well as using normal cloves. The taste does not change at all when the color shifts to green or blue. I have made many batches of pasta sauce with green cloves and nobody at my table could tell any difference at all.
Some garlic types turn green more than others when you store them cold for a long time. Certain varieties contain higher levels of the compounds that create those green pigments in the flesh. If greening bothers you, try growing or buying different garlic types to see which ones stay white longer in your storage.
Your storage setup matters more than anything else for keeping garlic looking its best and stopping garlic turning green. Pick a cool dry spot away from sunlight with temps above 50°F (10°C) to stop the greening process from starting. Mesh bags or wire baskets give you the airflow needed while keeping bulbs in the safe temp range.
Read the full article: When to Harvest Garlic and How to Do It Right
