Onion harvest from way back in 2011.

Every year, I do my best to grow enough onions for our own use that I don’t have to buy onions at the store. This is kind of a silly point of pride, as store bought onions are inexpensive and even when conventionally grown have a low residual pesticide residue. But there’s just something about having a storage pantry full of onions I grew myself that makes me feel rich in a way that buying from the store can’t provide. So I try to store 100 storage onions in the fall. (Figuring a rough average of two a week for 52 weeks, when in reality some weeks are higher and some lower depending on what else is in season and whether or not its stew season).

Storage only lasts so long. Eventually they sprout. This was Copra, a hybrid known for its long storage, harvested in fall 2017 and this picture taken in May 2018. Nine months is a good benchmark.

I grow my onions from seed rather than sets or plants, for a bunch of reasons. I’ve never had good luck with sets not sending up a flower stalk, making the onions next to useless for storage. And plants are expensive, and tended to produce a lot of splits (multiple bulbs under one outer skin), which also don’t store well. The size of the plants is also often poor. Last and most importantly, there is a MUCH wider selection to choose from when you grow from seed.

So I grow long day varieties from seed, which I start in a greenhouse (or germination chamber) at about the same time I start my tomatoes and peppers in March. They get planted out mid May, about the same time as the tomatoes/peppers. This year I planted about half of mine with a Stand-N-Plant, and I’m never going back. Saves your back, AND a ton of time. Best $50 I’ve ever spent.

Cipollini’s, which I’ve been growing for years. “Sweet, dependable, easy to handle and delectable, this Italian heirloom is the quintessential boiling and braising onion. Shaped like a button, up to 4″ wide (normally 3″) but less than 1″ thick. Flattened spheres with bright shiny golden skin. Fine-grained mild flesh with a well-developed flavor. Appreciated in soups, stir-fries and shish kebab.”

Years back (2013?), I got really interested in seed saving, as a way to 1) save money, 2) stick it to the big commercial seed companies and 3) adapt varieties to my local growing conditions. Because we live in prime onion growing country (when you say Walla Walla, most people think first of the Walla Walls sweet onion), I thought it would be fun to save onion seed.

In my early enthusiasm, I didn’t think a lot about how onions are pollinated (they are out-crossers), or whether or not the onion I was saving seed from was open pollinated or a hybrid (most storage onion seed is hybrid to emphasize long storage and disease resistance). So I plunked down some onions that were sprouting from the year before (a mix of heirloom Borrettana Cipollini, Rossa Lunga di Tropea (torpedo shaped) and hybrid storage Copra and Redwing) and let them send up seed stalks. (Onions are biannuals – meaning they go to seed the SECOND year of growing). Everything crossed of course. And I ended up with a couple of ounces of mixed/crossed onion seed. (An ounce of onion seed is approximately 8,500 seed). Woops.

On a whim one spring, as I was starting flats of onions, I decided what the heck, and planted a flat of the mixed origin seed. Germination was off the charts. The grow out produced some interesting mixes, including pink cipollini shaped onions, a LOT of torpedo shaped crosses and a few round globe yellow and red onions. Because I didn’t have a lot of room for these unexpectedly prolific germinators (germination is considered good in onions if its 88% – I’m sure I was WAY higher than that), I planted them out fairly close together wherever I could fit them in, and ended up with a lot of fairly small funky looking onions. So I bagged them up in “heirloom mix” bags, and to my surprise, they sold very well at market.

Mixed heritage onions from 2018.

I’ve continued to plant out this seed every year (did I mention HOW MUCH SEED I had!?) and the variety has been great fun. But this year I decided I really wanted to start over and really do a search for an open pollinated yellow storage onion that I could refine over time. Turns out its surprisingly difficult to find open pollinated yellow storage onions, though I did JUST discover Siskiyou seeds, who carries most of the varieties I tried this year.

I ended up trialing 6 yellow storage onions and one red storage onions this year. All seed was packed for 2019 except for Newburg, which was a sample packet I picked up at a conference in 2016 and then lost track of for a coupel of years.

New York Early Yellow Storage from Johnny’s. Described as “One of the more dependable and productive early onions. Medium-large, blocky, firm, yellow onions are early and suited to medium-term storage. Its flesh is more tender than the extra-hard, long storage varieties.”

Clear Dawn Yellow Storage from Fedco. Described as “Bred out of Copra. The best open-pollinated storage onion, Dawn has gotten better and better over years of selection with great storage capability. 8–10 oz average and very hard.”

Newburg Yellow Storage from Adaptive Seeds. Described as “Simply the best open pollinated yellow storage onion. Originally selected from a European commercial hybrid storage onion, it was reselected under and for organic production. The tightly wrapped, copper- skinned, spherical bulbs are known for their excellent storage life, crisp texture, and medium hot rich flavor. Newburg has out-yielded hybrids when trialed under organic conditions, making it a great replacement for the classic hybrid, Copra.”

Yellow of Parma Yellow Storage from Seed Savers Exchange. Described as “A top-quality, late-maturing onion with golden, globe-shaped bulbs weighing an average of 1 pound, this variety hails from northern Italy. It has a mild, sweet taste when fresh, but its flavor intensifies when it is stored. One of the best onions varieties for storage.”

Cortland Yellow Storage from Peaceful Valley Organic. They originally had it listed as open pollinated, which is why I purchased it. When looking up additional information on the variety, I came to realize they had it mislabeled, and its actually an F1 hybrid. I pointed that out to them, and they have since fixed the listing. So Cortland became the control for the trials, which isn’t a bad thing. “Cortland is the new onion on the block, developed from Prince and Copra for even longer storage. Orange-yellow, thick skin on large, uniform, round onions, 3-4″ diameter. Tolerant of pink root and fusarium.”

Dakota Tears Yellow Storage from Fedco Seeds. “Dakota Tears was more than 20 years in the making. Though you might cry when you cut one open—their flavor is robust and oniony—you won’t weep about their impressive production of very hard yellow bulbs with medium-thick necks averaging 1 lb each with no doubles. Holli Cederholm says hers keep till May under good storage conditions.” Can I just say, worst name ever for an onion.

Rossa Di Milano with its distinct flat top.

Rossa Di Milano Red Storage from Fedco Seeds. I’ve had less luck with long storage on red onions, though the hybrid Red Bull did fairly well for me. But I was ordering from Fedco anyway, so figured why not give this open pollinated variety a try. Described as “This excellent red Italian storage onion is shaped like a buttercup squash without the button. It has the flat square-shouldered top tapering like a barrel to a narrower flat bottom. A few years ago our supplier lost this typical shape. Now Rossa has been reselected for three years by our stateside grower for both form and storage. Tops slow to go down. Encourage the recalcitrant ones by pushing them over. Takes a while in fall to dry. Very hard and keeps a long time, till May for Vigue.”

I plant my onion seeds in flats by just scattering seed over the soil surface, rather than an even spacing or using individual celled flats. In my experience, when transplanting, the roots of onions are so wiry that all the soil falls off them anyway, so individual cells just leads to root spiraling and stunted growth. Root disturbance is inevitable when transplanting, so there’s no point. Better to give them more room/soil. After seeing the idea at another farm, I plant most of my onions in shoebox sized clear plastic 6 quart Sterilite containers purchased at a big box store, after drilling holes in the bottom for drainage. Onions have deep roots, and planting in standard 10 x 20 flats leads to huge root tangling by the time the onions are ready to be planted out. It’s also harder to keep the seedlings well watered as they grow in these shallow containers (I once lost several flats after they dried out too much on a hot sunny day). The Sterilite containers are deep, sturdy and reusable. The scatter planting saves a TON of time.

6 quart Sterilite container

Onions will germinate at fairly low soil temperatures (low 60’s), but you’ll get MUCH better germination if you treat them like tomatoes and peppers and throw them in a germination chamber where the temperatures are in the high 70’s. We convert our walk-in cooler to a germination chamber in the early spring by putting germination mats in there. It’s so well insulated that a few germination mats will bring the temperature of that small room up into the high 70’s pretty quickly in March. I plant in my standard potting mix and lightly cover seed with vermiculite. When conditions are good, I start to see germination in about 5 days. At that point, they either go under grow lights or get transferred into the greenhouse, depending on the weather. Seedlings can take a light frost, but will do better if you can avoid one. The lids to the sterilite containers make a quick cover to protect from a light frost when the plants are still small.

Onion germination guide from Johnny’s.

The onions get planted out in mid May, just after our last frost date (or as soon as I run out of room in the greenhouse and have time to get them in the ground). Using the Stand-N-Plant, onions are removed from their tray, roots trimmed to about 1/2 inch, tops trimmed down a bit, and then planted one at a time about 8″ apart in three rows, with 8″ spacing drip tape between the rows. All of this disturbance seems crazy invasive, but trust me, your onions will be just fine, and they don’t even seem to slow down if you can get the timing right.

I generally plant in beds that have been mulched with maple leaves the previous fall, and then fertilized with a mix of feather meal (nitrogen), gypsum (my soil is alkali and low in calcium) and a bit of kelp meal and azomite for trace minerals in the spring before tilling. My soil has plenty of phosphorus and potassium, so I don’t add those nutrients. My garden beds are functionally organic (ie I’m following organic methods, while not certified).

Nick and Charlie, hand planting leeks in early May.

I may do a foliar spray/drench of fish fertilizer when plants are about a month old and again before they start to bulb up in late June. Studies have shown that additional fertilizer once the plants start to bulb is pointless. Once they have made that genetic change from growth to storage, the die is cast.

Time to maturity estimations on seed packs are from time of TRANSPLANT, not time of direct seeding (unless its a green onion/scallion). It generally ranges from about 100 to 120 days. In our area, plants start to bulb up in late June and are generally out of the ground by early September. Keep in mind this is NOT the timetable for sweet onions like Walla Walla’s, which are grown from seed sent to a southern state location in the winter due to disease pressures, then returned and planted out in early spring. They start making their appearance at markets here in mid June, and are generally done by mid August. Walla Walla Sweets (along with the other sweet onions like Maui, Bermuda and Vidalia) are generally high in water and sugars and do not store well. They are meant to be eaten within a few months of harvest).

Starting to bulb up in late June. Hooray!

For this trial, I planted .5 g of seed (I have a small scale and actually measured) per container on March 11th. This was about 100 seeds, give or take (I was NOT going to count them). This volume was partially arrived at by the smallest seed pack I had on hand, which was a free sampler pack from Adaptive Seeds. With the exception of the Rossa Di Milano (which was terrible), I had good germination on all varieties (I did not count total seedlings).

When planting out, I planted the largest seedlings of each variety (generally about the diameter of a wooden chopstick) in blocks. In some varieties, most of the seedlings were quite large. In others, there were a lot of smaller ones. Because I was just frantically trying to get plants in the ground in May, I did not count how many of each variety was planted or note which ones had the largest seedlings. I figured it would be somewhat obvious based on final weight of the yield. All leftover small seedlings were planted together in a final block, anticipating smaller bulbs that could be bagged and sold at market without keeping track of variety. Some of THOSE seedlings ended up making surprisingly large bulbs (normally the smaller the plant, the smaller the resulting bulb). But because I didn’t keep track, I don’t know if one variety managed to surpass another when it came to starting behind in size.

All trial onions were planted in one 100 ft row, 8″ apart and 3 across. Varieties were separated by a flowering plant or herb to mark the change. Everything was transplanted on May 18th, and everything was out of the ground by September 1st.

Expected maturity order, based on seed packet “Days to Maturity” was New York Early (98), Clear Dawn (105), Newburg (110), Yellow of Parma (110), Cortland (110), Dakota Tears (112) and Rossa Di Milano (114).

Actual maturity order was Yellow of Parma (80), New York Early (80), Clear Dawn (94), Newburg (94) and Rossa Di Milano (94), then Cortland (101) and Dakota Tears (101).

So some surprises there. Harvest was generally over a two week period, where every few days, we’d pull whatever had fallen over recently (which is how you know an onion is ready to be harvested).

Onions were placed into open storage bins (one per variety) and stored in the greenhouse to dry down. They were then cleaned up, trimmed up and weighed in early October. There is some debate about whether or not people WANT onions that are over one pound (16 oz). I had a LOT of big onions.

VarietyTotal Yield lbsAve. wt. of 5 largest bulbsOther Observations
Rossa Di Milano813.8Terrible germination. Tended to get sun scald/soft spots during dry down. Flat top may make full dry down difficult.
New York Early18.110.8Really low yield. Most around 10 oz each.
Clear Dawn25.411.8Most much smaller than the 5 largest.
Yellow of Parma3216Most ranged from 13-16 oz in size. Deep copper rather than yellow color.
Cortland33.117.9Many close to 1 lb. Most similar in size.
Dakota Tears39.817Many over 1 lb.
Newburg4015.6Somewhat flattened tops. Flat top may make full dry down difficult. Wide variation in size. Highest BRIX (see below). Surprisingly good germination given that the seed was from 2016.

I’m not a fan of raw onion. I never have been. I pick them off of my burgers and out of my salads. If I eat them, they stay with me for hours and hours. So I did not do a raw side by side taste test of my trial onions (I also assumed that after the first bite, my palette would be pretty blown to detect subtle differences in the following tests). But I DID want a way to quantify the sweetness of the onions I grew this year.

Brix Refractometer

Brix measurements – a test of dissolved solids in the juice of a fruit or vegetable, has become all the rage with the bionutrient growers. I’m not overly convinced that its all they say it is, (is a sungold cherry tomato REALLY more nutrient dense than a sweet 100 because it has a higher brix reading, or does it just contain more sugar?) but it IS a good measure of the sweetness of something, be it a piece of fruit, a batch of jam, or an onion. So I bought a brix meter from Amazon, and as part of this trial, tested the brix of each of the varieties I grew this year. (All grown under as similar conditions as I could make it). A medium sized sample onion was pulled and marked, and then part of each sample was grated on a box grater, and the resulting pulp squeezed through a jelly bag in order to get a few drops of juice to place on the prism of the refractometer. I did NOT measure multiples of the same variety (and the leftovers from the sampling got turned into French onion soup). The results were quite interesting. For comparison, on of my Tropia onions came in at 11.

Brix testing candidates. Ignore the incorrect spelling on Newburg.
Rossa Di Milano7.5
New York Early9
Clear Dawn9
Yellow of Parma7.5
Dakota Tears8

The 10 largest from each variety were boxed and put into my garage pantry. Part 2 of this trial will be posted in late spring next year, after I’ve had a chance to see which varieties stored the best. It will be interesting if there is any correlation between brix/sugar content and storage. Right now I’m not a big fan of New York Early or Clear Dawn, neither of which seemed to do particularly well in our climate. I was worried about Newburg due to the slightly flattened top (flat tops don’t seem to dry as well), but the brix number, high yields and the fact that its been bred specifically for organic production makes it look pretty darned good right now. Winners of the storage trial will be planted out and seed collected. I may even try crossing the top two, depending on which traits I want to preserve (earliness, size, storage, brix…)

© 2019 Miles Away Farm, where we hope to breed the very best yellow storage onion for our area in the next 5 years or so, or at least grow a lot of yellow onions while trying.