Success with Spinach for Fall, Winter and Spring

January spinach from our second hoophouse sowing.
Photo Pam Dawling

Success with Spinach for Fall, Winter and Spring

Spinach is a much-loved crop for us. We sow outdoors and in the hoophouse in early September for harvesting from fall through to spring (April). We sow outdoors in late September for a crop to overwinter as small plants and be harvested in the spring. We also sow in our coldframes in mid-September. These are more sheltered than the beds outdoors, and the spinach makes faster growth. We sow more spinach in the hoophouse in October and November. We sow in the hoophouse in January to transplant outdoors and in the hoophouse in February for spring harvests. We are able to keep harvesting spinach (leaves, not whole plants) from October 15 to May 25, all the way through the winter. Central Virginia is too hot to have spinach during the summer (we switch to chard).

Spinach over-wintered in our cold frame
Photo wren Vile

Unsurprisingly, I have written about spinach several times.

Spinach Variety Trials Conclusion in May 2019. Our top general favorite is Acadia, although Reflect does better outdoors overwinter. This post includes links to earlier posts about spinach varieties, including Spinach Trials Update, April 2018.

What causes spinach leaves to turn yellow, in May 2019

yellowed spinach in May. We had transplanted too soon after tilling under some big weeds.
Photo Pam Dawling

A bed of healthy green Reflect spinach on May 3
Photo Pam Dawling

What makes vegetable crops bolt and how can I stop it? March 2021

Spinach Varieties

Choose varieties that do well in climates similar to yours, in the conditions you have when you plant and harvest. We used to grow Tyee for all plantings, and were very happy with it. But it has been pulled from the market because it had disease problems in the Pacific North West, where spinach seed is grown. We have tried and not continued Chevelle, Corvair, Renegade (grows fast, but has thin leaves and bolts early in spring), Avon (Downy Mildew in winter).

Also see the 2015 Greenbank Farm Spinach Variety Trial. The farm is in Washington State. They evaluated 10 varieties of savoyed and semi-‐savoyed spinach with two side-‐by-‐side replication in spring. Abundant Bloomsdale, Bloomsdale Long Standing, Butterflay, Giant Winter, Dolce Vita, Longstanding Bloomsdale, Lyra, Solstizio, Tyee, Winter Bloomsdale. The overall star of their trial was Solstizio from Nash’s Organic Produce.

Spinach plants on February 5. left to right: Avon, Renegade, Escalade, Acadia.
Photo Pam Dawling

Paul and Sandy Arnold in Argyle, New York, made a great slide show reviewing Spinach Varieties in High Tunnels. I think it’s no longer available online, but I did learn that in 2019, their top Winter Spinach Varieties were Escalade, Carmel, Whale, Space, Reflect; top Summer Spinach Varieties: Banjo, Seaside, Woodpecker.

In 2011-2012, High Mowing Seeds in northern Vermont did a spinach variety trial with 24 varieties. Three farmers in Iowa conducted a 2021 trial of spinach varieties and seedling methods. They compared yield, bolting and yellowing among three spinach seeding methods: seeder (1x rate), seeder (2x rate), hand-seed (2x rate); and between two varieties (Kolibri, Kookaburra). Two of them found no statistically significant difference of seeding method on yield; one found no difference in yields between the two varieties, but using a seeder at a double rate produced significantly higher yields than the other two methods.

When to sow fall spinach

Spinach does not germinate in hot soil! Use a soil thermometer and wait for the soil to cool to 68F (20C), or see the next section about sprouting spinach seed in a cold place. If you have no soil thermometer, see my post chickweed, hen-bit and dead-nettle, and use the info that was originally written with lettuce in mind, for spinach! There are photos there of these three plants at seedling stage. These are winter annual weeds here, that don’t grow in summer. Once we see their seedlings emerging in late August (a cool summer year like 2023) or September (most years) we know the soil has cooled enough to sow lettuce and spinach directly in the ground.

A trick for getting good timely germination of spinach seed is to put it (in sturdy resealable plastic bags or jars) in the freezer for about two weeks. Take the seeds out of the freezer the day before you want to sow (or start sprouting them), but – important – do not open the bag or jar. Leave it to warm to ambient temperature before opening. Otherwise the warm humid air will rush in and coat the cold seeds with condensation, reducing the shelf life of whatever seed you have left over for another time.

See our Spinach Variety Trials and Planting Plan, in February 2018:

September 6 is our first sowing (sprouted seeds) in the hoophouse for winter harvest 10/30-2/15, or later if it doesn’t bolt.
We sow outdoors on September 7 (sprouted seeds) for growing under rowcover and harvesting in fall and winter.
September 18-20 we sow in our coldframes and outdoors for harvest in early spring, until late May.
October 24 we make our second hoophouse sowing, to feed us November 25 to May 7.
On November 9,we make a third hoophouse sowing, intending to use these plants to fill gaps in our hoophouse as other winter crops come to an end.
January 16 we make more sowings in the hoophouse, some to continue to fill gaps there along the edges of the beds where they won’t fight with the tomatoes and so on, which we transplant starting March 15. Most of the spinach sown on this date is for transplanting outdoors on February 21.
January 29 we sow in flats in the greenhouse if we see we haven’t got enough bare-root transplants in the hoophouse.
February 10 If we don’t have enough transplants, then on this date we sow outdoors with rowcover, for spring harvests until May 25 if we’re lucky. We have backup plans on backup plans for this!
In the hoophouse we continue transplanting spinach to fill gaps until March 31.

Sprouting seeds before sowing is a way to success in hot or very cold weather.
Photo Pam Dawling

Sprouting Spinach Seed

This very easy work-around involves soaking the spinach seed in water overnight, draining it, and putting the jar on its side in the fridge for a week. If you remember, give the jar a quarter-turn each day to even out the moisture. You are not growing bean sprouts! A little neglect will not cause harm. The ideal is to have short sprouts, not long ones, as those break off more easily. Sow the seed in the furrows gently, by hand. If the sprouts have got tangled, add some water to float them apart, drain them, spread them on a tray, or a layer of rowcover, to dry a bit, then mix with some inert dry soil-friendly material like uncooked corn grits or bran, which will help them not stick together.

Sowing Spinach in Speedling Flats and Floating them in Water

Another option is to start the spinach in flats and transplant it all. That’s a lot of work, but we found we could save on the daily attention time and the transplant time by using 120-cell Styrofoam Speedling flats. Sow one or two seeds per cell, then float the flats all day in water. Depending on your scale, this could be a baby bath or a stock tank. Remove the flats each evening and let them drain all night (while it is hopefully cooler). With just twice a day visits and no hand-watering, this is a big time saver, and we have got good germination rates.

Transplanting spinach from a Speedling flat. Butter knives are the tool of choice for easing the little wedges out of the tapered cells.
Photo Denny Ray McElya

When it comes time to transplant, the tool of choice is a butter knife. Use the knife to wiggle a wedge-shaped hole in the bed. Slide the knife down the sloping side of the cell, and, holding the base of the plant with one hand, use the knife hand to lift and flick the plug out. If all goes well, the plug will be then be resting on the now-horizontal knife, and you can slide it into the pre-made hole and firm it in.

Growing Spinach

Spinach makes growth whenever the air temperature is 40F (4.4C) or more. So any winter protection you can provide, in the way of cozy microclimates, rowcover, coldframes, or a hoophouse, will increase your yield. Spinach is more cold-hardy than many people realize. It dies at 0°F (-18°C) unprotected outdoors. Savoyed varieties tend to be a little hardier than smooth-leaved types. Large-leaved savoyed spinach outdoors with no protection can get seriously damaged at 10F (-12C). Small-leaved plants are OK down to 5F (-15C).

Weeding rowcovered spinach in winter.
Photo Wren Vile

Our outdoor spinach gets hoops and thick rowcover (Typar, 1.25 oz/sq yd spunbonded polypropylene, with 75% light transmission, and about 6 F (3.3 C) degrees of frost protection). It can last for 6 years or more. When we got 0F (-18C) the spinach leaves that touched the rowcover got big patches of beige/tan dead cells, but the plants recovered to produce more leaves.

Ben Hartman (author of The Lean Farm) wrote Testing the Limits of Cold Tolerance in Growing for Market magazine in February 2014. He reported that his young hoophouse spinach in Goshen, Indiana, with mid-weight rowcover survived -16F (XXX). Ben points out that spinach less than 1″ (2.5 cm) tall is very cold-tolerant. Bigger plants need more protection if it’s going to get that cold.

You can read more about growing spinach in my Cooking Greens monthly series.

Growing bare root spinach transplants

Small spinach seedlings for bare root transplants. Photo Pam Dawling

We grow our spring spinach transplants (as well as kale and collards) in the soil in our hoophouse, sowing them in late January. See bare root transplants . You can find more links and info in that post. Growing bare root transplants saves a lot of work and a lot of greenhouse space.

Harvesting Spinach

Our goal is sustainable long-season harvesting. This is important for winter crops, as making a new sowing during cold dark days will not produce much food until spring comes around. It’s like the goose that lays the golden eggs – keep the leafy “golden eggs” coming

We harvest spinach by cutting individual leaves and leaving the plant to continue to produce more.

Our rule is “Leave 8 for later” – cut off large outer leaves close to the base of the plant, being sure to keep at least 8 of the inner leaves growing on each plant. Over-harvesting leads to decline.

When we finally pull up the bolting plants in spring, I’m always amazed to see how many leaf-scars there are on each plant, showing just how much we’ve harvested.

Hoophouse spinach. Far row: bolting Renegade; Near row: Escalade.
Photo Pam Dawling

For those relatively new to this blog but living in a similar climate zone, I want to point you to The Complete Twin Oaks Garden Task List Month-by-Month. It includes a link for each month’s task list. I notice from the site stats that some of you are finding your way there, but now there are so many years’ worth of posts it’s perhaps harder to find. Happy browsing!

Stale seedbeds, triage farming, vertical farming

This week I have for you several sources of information related to small-scale sustainable farming.

Hoe the small weeds in this bed of young lettuce soon, and the closing canopy of the lettuce will shade out most weeds after that. Photo Bridget Aleshire

Triage Farming

Growing for Market has posted Triage Farming by Matt S. as a free article on their website

Matt tells of becoming farm manager on a new piece of land, with terrible drainage problems and lots of grass weeds.

“There are five spheres in which a farm can be challenged. Most farms deal with serious disadvantages in one or two of these. We were handicapped in four.” The five are location challenges, site challenges, infrastructure and equipment challenges, institutional challenges (dealing with the bureaucracies), human challenges. They didn’t have human challenges!

As a response to kicking around dried mud-balls full of grass bristles, Matt invented Triage Farming. Triage (from the French trier ‘separate out’) was a concept that came into wider use during WW1 as medics had to sort injured soldiers into three groups: those that would be OK without treatment really soon, those that were going to die whether they had treatment or not, and those who would get the most value from immediate treatment. In farming it means prioritizing using your limited resources to their maximum effect when it’s impossible to accomplish all you hoped to do.

This is not a sustainable way to farm (or live). It’s a way to preserve sanity and be most effective when things have got out-of-control. It doesn’t leave a feeling of satisfaction. But nor a feeling of despair. It can be ruthless, sloppy and minimalist.

Maybe you have never had such moments, but I have. If you have, then I recommend this article. Keep a copy handy, especially in the heat of the summer. You’ll likely not agree with every decision Matt made, but the article will help you raise your head and look around, rather than keep pushing on the task at the top of the schedule you made back in January.

Matt helps with deciding which crops to grow, and how much, if you know it’s likely to be a difficult year (new site, brand new crew, etc). He works through each of the five challenge spheres he identified and explains his response to that aspect: suitable crops for different location challenges, suitable equipment, approaches to weeding (timely, untimely, and “carnage weeding”), tools and equipment for different situations, dealing with various bureaucracies, and how to delegate to other workers.

Matt has an uplifting style, which also helps when the going gets tough.

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False and Stale Seedbeds

I just read a very clear 25-page publication about using false seedbeds and stale seedbeds, including flaming. False and Stale Seedbeds: The most effective non-chemical weed management tools for cropping and pasture establishment. Dr Charles N Merfield, 2013. Lincoln, New Zealand: The BHU Future Farming Centre www.bhu.org.nz/future-farming-centre

Screenshot 2023-07-31 at 13-45-27 False-and-stale-seedbeds–the-most-effective-non-chemical-weed-management-tools-for-cropping-and-pasture-establishment-2015-ffc-merfield.pdf

“False and stale seedbeds are based on three rules:

most weed seeds are dormant,
tillage is the most effective means of germinating weed seeds, and
most weeds only emerge from the top 5 cm / 2” of soil.

Both false and stale seedbeds work by the very simple process of germinating the weeds then killing them and then growing the crop.
False seedbeds use tillage/cultivation to kill the weeds.
Stale seedbeds use thermal weeders or herbicides to kill the weeds.”

Both false and stale seedbeds are made by preparing the bed 7-10 days before you plan to sow your crop, watering if the conditions are dry, then killing the carpet of emerged weeds, by very shallow tilling, hoeing or flaming. Getting the tillage correct is critical, including having a good weather-eye. Flaming will kill broad-leaved weeds, but only set grasses back by about a week. Alternatively, cover the prepared bed with a tarp to germinate and kill the weeds.

The 5-15% of weed seeds that are non-dormant are mostly in the top 5 cm/2” of the soil, and germinate very quickly. These can be very effective techniques, and this publication explains them well, and has good photos of crops, and machines such as the milling bedformer and the roller undercutter, and some fancy flamers and steam weeders, which might be equipment to aspire to, while working with spring tine weeders and shallow tillage. The explanations help with getting a better understanding of weeds seed germination, and so how to succeed with pre-plant tillage and post-crop-emergence cultivation. Timing is important, as is having the right tools for the job.

There’s also a good relevant article in Growing for Market:

Tools and strategies to reduce time spent weeding by Sam Hitchcock Tilton

Definitely read this if you are spending a lot of time weeding, or your crops are over-run by weeds. Work towards reducing your weed population each year, by preventing weeds from seeding. “Realize that one lamb’s-quarters or kochia or bindweed or galinsoga plant going to seed can be a much bigger problem next year than 10 or even 100 non-reproducing plants are now. So marshal your precious weeding resources smartly.”

Timely hoeing, while weeds are tiny and quick to die, can prevent the need for pulling weeds by hand, if you are working on a quite small scale. If your scale needs other tools, here you can learn about equipment to physically control weeds as part of your cropping system. If you are using a 4-wheel tractor, consider hillers, mini-ridgers, finger-weeders, Spyders, beet knives (L-blades), tine weeders, basket weeders.

A Thiessen walk-behind tractor cultivator, with Spyders up front, with the front of the Spyder angled towards the crop row (to pull soil away from the row), and torsion weeders at the back to weed in the crop row.

The article includes some equipment for 2-wheel walk-behind tractors, such as the Thiesson cultivator, Buddingh and Tilmor basket weeders, Even wheel hoes have weeding attachments.

Sam also describes stale seed-bedding, and advises rolling the prepared bed before tarping or watering, to provide the weed seeds good contact with the soil.

Sam’s article includes excellent photos, a tailored-for-beginners’ explanation of which tool does what and many links to other website and videos.

As Ben Hartman points out in The Lean Farm, hand-weeding is in a sign of failure to act sooner, that has led to a time-wasting scramble to correct the situation. read my review of The Lean Farm.

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Here’s an article from USDA on Killing the Crop Killers—Organically

As an alternative to bromide fumigation to kill pest nematodes, and other pests, try anaerobic soil disinfestation (ASD), an organic treatment that temporarily removes oxygen from the soil, is inexpensive and easy to apply. This method involves using a source of carbon, such as orchard grass, or mustard seed meal, tilled into the soil

Lean Times Hit the Vertical Farming Business.

Vertical farming is a code for a type of high tech hydroponics. See this article on the BBC website. Yes, hydroponics uses a large amount of energy to grow the plants. Yes, growing plants takes skill and attention. Yes, growing only a few crops is risky: people will only eat so much lettuce. Aerofarms has filed for bankruptcy, and several other “vertical farming operations” have hit financial troubles too.

Balance that with this post by Lee Rinehart from ATTRA:

Real Organic: Reflections on “The Deep Roots of Organic in Soil” by Paul Muller.

Soil is complex, with a universe of microorganisms, and cycles of carbon, nitrogen, hydrogen and many other elements. Farmers are part of the cycle. Organic farmers are seeking to make continuous improvement to the life in the soil, by observing patterns and lifeways, mimicking the native systems. We are not the center of the universe. Wendell Berry says “We don’t know what we are doing because we don’t know what we are undoing.”

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Plastic in the Organic Supply Chain Conference Report

From Modern Farmer

In early May, the Organic Center and the Organic Trade Association held the Organic Confluences conference about Reducing Plastic Across the Entire Organic Supply Chain. “While plastics serve many practical purposes on organic farms as well as for packaging and distribution, plastic production, use, and disposal cause massive amounts of pollution, which disproportionately affects low-income people and communities of color in the United States and around the world. At the conference, farmers, researchers, policymakers, wholesalers and retailers, nonprofit organizations, government agency staff and many others gathered to define the challenges in reducing plastic use, identify research needs, highlight success stories, and discuss what needs to be done to solve this growing problem.” Read a report about the conference on the eOrganic website here, with links to the conference program and slide presentations.

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Young spinach seedlings.
Photo Pam Dawling

Spinach Trial Underway to Inform Organic Seed Production

The Organic Seed Alliance is evaluating 272 spinach accessions from the USDA-ARS Germplasm Resources Information Network (GRIN) seed collection at their research farm in Washington State to assess timing of bolting and seed yield potential as part of a NIFA OREI funded project. This fall, they will share the trial results as well as their knowledge on spinach seed production and seed cleaning techniques through a webinar hosted on eOrganic, but meanwhile, read more about the project on their blog post here!

The seed production trial information is a part of an effort to aid in developing better varieties for organic farmers. “Research on the role of soil microbes on nutritional content, nitrogen use efficiency, and abiotic stress such as extreme temperatures is also underway by the project lead researcher Vijay Joshi at Texas A&M, and Ainong Shi and Gehendra Bhattarai at University of Arkansas. Together with the results of the seed production trials this project will help inform organic spinach breeders and farmers, and anyone working with seed from the USDA-ARS Germplasm Resources Information Network (GRIN) seed bank.” Results will be posted on the eOrganic project website.

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Tomato Breeding Project Fueled By Over 1,000 Backyard Gardeners

Some of the Dwarf Tomato Project’s diverse harvest. Courtesy of Craig LeHoullier

This 12-minute segment from Science Friday is an interview with Craig LeHouiller, who is a gardener/garden writer / tomato breeder in North Carolina. He is the author of Epic Tomatoes. In this segment he talks about the open source Dwarf Tomato Project. He and collaborator Patrina Nuske-Small aimed to preserve the flavor and beauty of heirloom tomatoes, without taking up too much space. They started crossbreeding heirloom tomatoes with smaller dwarf tomato plants. They signed up over 1000 volunteers across the world. They now have over 150 varieties of dwarf tomatoes, everything from cherries to beefsteaks, in every color. You can buy seeds from Victory Seeds, who have dedicated themselves to offering every dwarf variety produced.

Planning and Growing Winter Hoophouse Vegetables

Hoophouse winter greens.
Photo Kathleen Slattery

If you have a hoophouse, you may now be planning or planting crops for fall, winter and spring. If you don’t have a hoophouse, this is a good time of year to consider getting one. See Twenty Benefits of Having a Hoophouse at the end of that post. There are grants available from NRCS, including reparation levels of funding from traditionally underserved groups of people. There are now companies that will construct your hoophouse for you, if you don’t want to do it yourself, or can’t. If you do want to build your own, there are detailed instructions in my book The Year-Round Hoophouse. You can buy the book here on my Books page direct from me, or from my publisher New Society, or you can buy it wherever books are sold.

I have many posts about winter hoophouse vegetables, so rather than try to write something completely new on the topic, I am going to give you a guide to find your way around the information already here.