When to harvest

How do you know when it's time to harvest your onions?

Once you figure that out and it really is time to harvest, what do you actually do? Let's dig in and find out.

Let’s say you’re reading the onion seed packet and it says the days to maturity are 105. Does that mean that you should mark off 105 days from when you sow them then harvest? Nope!

Varying weather patterns from year-to-year means that the “days to maturity” for all vegetables is just a rough guideline.

In the maritime Northwest, many vegetables mature later than in the rest of the country.  So use “days to maturity” to compare different plants and varieties.

Luckily, onions are a vegetable that will give you an obvious visual sign as to when they’re ready to harvest.

One day you’ll walk out to your garden and see that one or two or maybe a few of the onion stalks have fallen over. That’s called “going tops down.” 

Here’s a picture from my garden this year at that stage.

Stop watering the onion bed at that point. You want things to start to dry out.

Within the next several days more and more of your onions will go tops down.  When about half of them have fallen over, push the rest of them over.  At that point they will look similar to the picture below.

Then you wait a week or 10 days (and hope it doesn’t rain).  If it does rain, I am usually going to pull a tarp over the onion bed.  I really like to keep things dry before harvest.

How to harvest

Before you harvest your onions, make sure you have prepared a place for them to cure.  Keep in mind that they will be sitting there for several weeks.  You will be curing the whole plant, tops and all, so allow enough space for that.

They need to cure out of the sunshine in an area with good air circulation.  In my barn, I use a section of wire fencing supported by boards that allows air circulation above and below the onions.  In the past, I’ve cured them successfully on a tarp in my garage.  In that situation I turn them over every week or so.  In any case a fan can be helpful to speed up the process by increasing air movement.

Once your curing area is set up, you are ready to dig your onions.  I have used shovels, digging forks and hand tools.  My favorite tool for this task is my Hori Hori knife. If you don’t already own one of these, you should get one.  It’s a contender for the most versatile, often used tool in my garden.

Your goal is to harvest your onions with as little damage/stress to the plant as possible.  That means no pulling up by the stalk and being careful when you dig not to damage the onion or the first few inches of roots.  Handle them gently!

When you get the onion out of the ground, gently break off any clods of dirt in the root section.  It should crumble away nicely if the onion bed has been dry for the past few weeks.  Don’t wash them off, keep them dry.

How to cure onions for storage

What does “curing” mean anyway? 

It means drying the onion plants to a point where they will store well.  Freshly dug onions are fine to use right away in the kitchen, it’s just that they won’t store very long.

After you’ve harvested your onions put them in a single layer in the place you prepared for them to cure.  Your goal is to dry them, so give each plant as much “breathing room” as possible.  Here's a picture of this year's crop laid out for curing.

The time it takes to cure them is dependent upon the temperature, humidity, and air circulation, so it varies from year to year.  A rough estimate would be from 4 to 8 weeks.

The main thing I watch for is the degree to which the tops (green parts) dry out. As you check the progress, you want to feel the stem right above the onion bulb.  It starts out green and pliable and will eventually turn brown and much firmer.  The best way to be sure is to cut the stem about an inch from the bulb and then look and feel for any moisture at all.  If you detect moisture in the stem, you can go ahead and use that one in the kitchen and keep curing the rest.

When your onions are thoroughly cured/dried, it’s time to clean them up and put them in storage.  I’ll cover that in detail in a future post.