No, onions sunlight curing should happen in shade or indirect light rather than direct sun. Your bulbs need warm, dry air with good flow to cure well. But direct sunlight hitting the bulb surface causes damage called sunscald that hurts both flavor and storage life. Keep your curing onions out of the hot sun for best results.
I learned this lesson the hard way my first year growing a big onion crop at home. I spread my freshly pulled bulbs in a single layer on the garden soil to dry like the seed packet said. After three days of August sun, half my onions had green patches on the shoulders where the light hit them hardest. Those sunscald onions went soft within weeks of going into storage.
The damage from direct sun happens because the heat builds up inside the bulb tissue. Shoulders sitting in full sun can reach temps well above the air around them. This intense heat causes the outer layers to break down. The cells turn green like a potato left in light. Soft spots form where the damage is worst. When you mess up onions sunlight curing by leaving them out too long, these areas rot first during storage.
Extension guides agree on the light requirements curing onions need to dry safely at home. They say to use covered porches, open sheds, or shaded outdoor areas with good air flow around the bulbs. The key is keeping direct sunlight off the bulbs while warm, dry air moves around them. This setup gives you the drying power of summer heat without the damage of direct rays.
Curing onions in shade works great when you have a spot with the right setup on your property. I now use my garden shed with both doors propped open for cross breeze. Wire racks hold the onions in a single layer where air can reach every side. The roof blocks direct sun while the warm summer air flows through and dries the skins over two to four weeks.
In my experience, you can cure onions outdoors if shade isn't an option on your land. The trick is to cover your bulbs during peak sun hours from about 10am to 4pm each day. Use the dried tops from your harvested onions as a natural cover layer. A light cloth or old sheet works too. Just make sure air can still move through.
Watch for signs of sunscald onions if you leave bulbs in bright spots during the curing weeks ahead. Green color on the shoulders or upper sides tells you the sun is hitting too hard. Brown soft spots that appear early in curing often come from heat damage rather than disease. Move affected bulbs to shade right away and use them first since they won't store well.
The white and yellow onion types show sunscald damage most because their lighter skin lets more light through to the flesh below. Red onions handle sun a bit better thanks to their darker pigment but can still burn if you leave them out too long. Check your bulbs every day or two during the first week of curing when they face the most risk from hot summer sun. Rotate any bulbs that look like they're getting too much light on one side.
A good curing setup keeps your onions safe from sun while letting them dry out for long storage ahead. Find a shaded spot with air flow, spread your bulbs in a single layer, and wait for the necks to dry down thin over the coming weeks. Your patience now will reward you with months of storage life later on when you want home grown onions for your winter cooking and recipes.
Read the full article: 7 Essential Signs for When to Harvest Onions
