🥔 how to grow and store potatoes + onions for year round eating 🧅
understanding their terminology plus july garden photos
Dusk is coming and the air is thick with humidity and cicadas. The kind of thickness that exists outside of time and makes you feel as old as the oak trees. The sound of cicadas and cooing doves seem woven into the dull heat itself, and I imagine myself a spider held stuck in the fabric of history, wondering how many years will continue to pass before this part of the planet returns to its jungle self? Every fern, bit of moss, creeping ivy; each eager to bury us quietly into the past. How many years did women sit on this porch, frizzy and sweaty, with their glass of water in hand as they put off the tomatoes that need to be canned? - journal, 7.7.22
We are back from visiting our respective families in Ohio and while I thought the previous weeks were hot, the humidity has now come and outdone itself. We live with condensation dripping down our 100 year old windows, and we are lugging our dehumidifier up and down the stairs.
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I took the camera out early this morning where the glass immediately fogged up. (This must be bad for cameras, right? Leave a comment if you know.) Here are blurry images. It didn’t even rain this morning; can you feel the respirating plants drenching everything?
My days are currently a mix of pruning, garden planning for clients, hauling soil, lumber, and plants around town, and figuring out how to eat tomatoes three times a day.
I thought I would write today about what I’ve learned on onions and potatoes. For some reason their planting schedules, harvest time, and storage have continually escaped my long-term memory and I am always doing things at the wrong time. I’ve never stored them well which has de-motivated me from growing them at a meaningful scale, but I am genuinely trying to learn how to live off our garden, and I want potatoes and onions as close to year-round as possible.
Three important notes:
Both are cool season crops whose prep begins during the winter - these are not your “plant for the summer garden” babies. Sweet potatoes are the outlier - they are grown during the summer.
Both can be planted out in the spring and in the fall, with caveats. Plant both this fall, and experiment. And then plant more in the spring!
The number of types of onions is truly overwhelming. Do not let it paralyze you. Focus on finding 1-3 kinds that work for you and forget the rest.
Key language to learn: You may hear about “new” potatoes. These are potatoes that are harvested before the above-ground foliage dies. New potatoes are typically what are used as ‘seed potato’; these will grow larger plants. New potatoes are also harder to store long term. When you grow potatoes, you’ll want to let the plant die almost completely so you can store for months. A seed potato is just a potato sold for growing, typically sold by the pound. A potato slip has already been sprouted with a few leaves; this is typically how sweet potatoes are sold.
When to plant them: A month before the last frost. In Zone 7B, I plant in early March. Can you plant later? Yes. Potatoes struggle once it hits 90 degrees, so the idea is to allow them to grow, flower and set potatoes before that happens.
Where to buy them: You can plant grocery store potatoes that have sprouted, as long as they are organic. Non-organic potatoes have been treated with poisons that keep them from sprouting, or severely limit their ability to grow. That being said - organic grocery potatoes will likely not produce the same yield. This is because most seed potatoes are “new” and more productive! To be honest, I’ve only used grocery potatoes for the last 3 years and next spring will be the first time I purchase ‘seed’; likely from Southern Exposure, Baker Seeds, or Johnny Seeds.
When to harvest them: Potatoes are divided into early season (60 days), mid season (80 days), and late season (90 days+) varieties. I’ve always popped whatever I have in the ground, and then harvested once they die off - but next year I may try one of each so that I can harvest potatoes continually. If you plant in March, you can roughly expect to harvest in June, adding additional varieties will stretch it to May-July harvest season.
How to store them: Cool and DARK! 42-50 degrees is preferable, but low humidity. I will be keeping them in my pantry until the heat drops, and then they can move to my basement. Store them in cardboard boxes or wood boxes with slats for air flow - not in plastic bins. Check periodically for a stray rotten potato and toss. If they start to sprout, no problem. Knock them off and eat those first.
Pro Tips: (1) You can also plant potatoes in late fall, and it will jumpstart them the following spring. If you do this, make sure they have great drainage and aren’t in a soggy spot. (2) Read about ‘hilling’ your potatoes to get a better yield. (3) Grow these in-ground OR in raised beds with a good mix of our local clay. Potatoes do best in acidic soil (4.5-5.5 ph) which is our native acidity. Raised bed mixes are closer to 6-7 ph. (4) In an effort to ensure they didn’t get soggy this year, I really let them dry out. Whoops. If planting in long rows, run a straight dripline and water them every few days.
Fun Fact: You can get 180 onions from a 4x6 bed.
Key language to learn: Short Day, Long Day, and Day Neutral. Short Day onions only need 9-12 hours of sunlight to set a bulb, while Long Day require 14-16+. For most of the country, Long Day and Day Neutral varieties are best, so the bulbs don’t form too quickly. If you’re in the southernmost band of this chart, you’ll likely want Short Day. The NC/VA state line is supposedly the line between Day Neutral and Long Day, but you can grow all 3 here if they’re planted at the right time.
When to plant 101: Onion grows via Seeds, Transplants, and Sets. They take 2.5-3 months to grow from a seed to a transplant size. So, you can buy a seed packet and plant out in the late fall or dead of winter, and cross your fingers. Or, you can also start them indoors (or purchase from nursery) and transplant them when they are itty bitty teeny skinny little babies (~6” tall, half the width of a pencil). Lastly, you can purchase “onion sets” which are very small bulbs that will then grow and expand into full size bulbs. I’ve done all three, and had the most luck (largest bulbs) with transplants that I start indoors. I start them indoors 3 months [Jan 15] before last frost and put them out 1 month [Mar 15] before last frost, unless hard frosts (under 28°) are on the horizon. They’re one of the few that keep longer in their trays without getting root bound.
When to plant 201: If you’re OBSESSED with onions or just want to master them, plant Short Day/Day Neutral onions in the Fall, and then Day Neutral/Long Day in the Spring. This will give you a continual harvest from May-July. More info here.
When to harvest: When 80% of the tops have flopped over and/or turned brown. You can pull one to eat whenever they’re big enough, but for storing a full batch you’ll want them to start to die off. IMPORTANT: If they start to grow a flower, cut it off asap. The stem with a flower is called a scape, and you can saute/eat it! The onion likely won’t grow much after bolting/going to seed. I cut the scape and let them complete the dying off process, but others recommend harvesting as soon as they bolt.
How to store: Onions have to “cure” to survive storage for several months. There are two methods: (a) Leave them outside in the sun for a day, and then move them into a garage or indoors and let them lie out on a table for 2-3 weeks. (b) Leave them outside in direct sun for a full week. — Either way, you just have to keep them ultra dry, with good airflow, and you want fully dry tops and a papery outer layer. Keep them out of rain or high humidity, and turn them often so you don’t get a squishy bottom. Toss any that go mushy.
Best onion varieties for storing: White Sweet Spanish, Yellow Sweet Spanish, Walla Walla, Brunswick, Stuttgarter, California Early Red, Red Creole.
Pro Tips: (1) If buying onion sets from a bulk bin [Clemmons Mill, Ace Hardware on Robinhood], don’t pick out the largest. Bulbs 1/2” in diameter are choice; anything larger is likely to bolt quickly rather than producing a good sized bulb. (2) Don’t over fertilize. Too much nitrogen will keep onions from bulbing. (3) When transplanting, grab scissors and cut down to 3-4” tall. This will help their roots get settled faster and tops to thicken up. (4) Onions are the only thing I’ve stopped planting “intensively.” They truly do need their space to bulb properly.
PSA: Elderberry Farms’ inventory is 50% off until July 29th. Now is the best time to visit and grab native perennials for your garden. <3
Until next time,