Production planning, successions, and crop rotations to maximize your high tunnel space in winter
by Joe Rowland, CFSA Organic Initiatives Coordinator | Wednesday, Jan. 11, 2023 –
I’m new to CFSA, if you didn’t know, and have the privilege of working with growers on season extension and high tunnels. When I started growing in high tunnels 12 years ago, I focused on the shoulder seasons. I wanted to grow earlier in the spring and later in the fall. So, I would make sure my tunnels were clean, clear, and raring to go by my March 15 target date for tomatoes. Similarly, I would have that tunnel packed full of beautiful greens and things in November and December as production slowed outside.
In hindsight, what I didn’t focus on enough was the doldrums of January, February, and March!
Sometimes that March, even April, timeframe was the leanest of all for me. Spring hadn’t quite sprung, but those cold-hardy crops had about given up the ghost, and on the first warm days, they were going to seed.
Repeatedly, I found that the fall and winter stayed warmer than usual through Christmas, meaning that I still had steady production in the field until that time as well, albeit slower to rejuvenate. I ended up with double the yields that I needed during those times, with the high tunnel duplicating what the field already had to offer.
By December/January, I was typically ready for a break. I would often plant a cover crop, leave the tunnel fallow, or carry fall crops along until time to prep for my tomatoes.
My advice to you is to not do this!
Those tunnels are so valuable at that time of year. Growers like Pam Dawling and the great folks at Wild Hope Farm (Chester, SC), amongst many others, have pushed the envelope in winter growing. Pam talks about using the outside beds of her tunnel as a nursery. She direct seeds cold-season, quick crops earlier in the fall, and when things play out, or she has gaps in production, she can simply prick out the seedlings, bare root, from the outer beds and move them to where they are needed. If this makes you nervous, you can grow them in trays as usual, but there’s beauty in letting the soil buffer these plants and provide them with moisture and nourishment that is not completely dependent on the farmers’ footsteps (and fossil fuels). Pam also uses her main tunnel beds as a nursery for early spring transplants. She directs seeds in January and later transplants bare root into the field once the weather warms.
Let’s look closer at Pam and Wild Hope’s winter high tunnel production plans. Keep in mind that Pam is in Virginia and Wild Hope in South Carolina, so take notice of how planting dates and days to maturity fluctuate.
PAM DAWLING’S HOOP HOUSE PLAN
There are a number of interesting points to make from the hoop house plan below.
The days to maturity change drastically based on planting dates later into the winter (as we will also see with the Wild Hope planting plan). The brassica salad mix and mizuna are interesting examples.
The salad mix is entirely direct sown. The 10/2 planting is ready in about a month, while the 1/27 planting takes over 2.5 months to harvest.
- The mizuna may show us the value of transplants in this situation. The 10/20 crop is transplanted and ready to harvest in about a month (though daylight and temperature in October may play as much of a role in this as transplant production).
- The following direct sown succession on 11/9 takes a whopping 3+ months to mature.
- As day length increases, the planting on 2/1 is marketable in about seven weeks.
So, from October to March, the same crop has been ready in 1 month, 3.5 months, and 1.75 months!?
Now let’s talk about Pam’s lettuce.
Look at all the cuttings off of the 10/24 lettuce mix planting! Up to eight cuts! But, the December and February plantings only get three harvests, if they’re lucky. This shows you how much things can slow down in the dead of winter. I also like that they are harvesting leaves from mature lettuce heads before harvesting the whole plant. This may not be efficient for marketing, but it is effective for sustaining a harvest for personal use.
Also, take a look at Pam’s 2022-2023 winter hoop house planting plan and her current planting plan. I like that she has tasks to complete built right into the planting plan. Similarly, I have used a large desk calendar in the past to visualize farm tasks and field prep that corresponds to scheduled planting dates.
A word to the wise: This time of year things grow slowly! It may take some trial and error and gleaning information from other growers to hit your targets. Don’t put all your lettuce in one tunnel (eggs in one basket) and expect everything to be ready when you need it. Spread the liability around by differing planting dates, varieties, and days to maturity. And if you really want to figure things out, keep good records.
Pam has a handy website and has published two books that may be of help to you:
- Sustainable Market Farming: Intensive Vegetable Production on a Few Acres
- The Year-Round Hoophouse: Polytunnels for All Seasons and All Climates
WILD HOPE FARM’S WINTER HIGH TUNNEL PLAN
At Wild Hope Farm, they operate a very successful winter CSA. Mary Stone, Peanut Belk, Shawn Jadrnicek, and Rachel Klein developed a production plan that can supply 100 individuals for ten weeks from January through -March using two) 30 x 96 high tunnels and minimal outside supplementation from the fields.
View Wild Hope’s Winter Planting Plan
With planting dates starting in September and October and continuing into January and February, they are working to perfect the system. As one crop plays out, they have transplants available or are direct seeding to fill a later need in the plan. The team at Wild Hope has been kind enough to share their winter high tunnel planting plan and field map with us.
First, let’s take a look at the Wild Hope field map. The color coding makes it very easy to see when crops go in and out of each bed. Some of the other useful information on the map is the succession number, target transplant date, and amount of bed feet to be planted.
When doing intensive plantings with quick turnaround times, it is critical to have an understanding of when bed space will be turned over and have target dates for re-planting that correspond.
These dates and ranges are targets and are somewhat specific to the micro-climate at Wild Hope, but they can be a great starting point for further investigation on your farm. A document like this would be good for you and your crew to have with you in the field as a guide when planting without getting bogged down by all the additional information included in the planting plan.
This field map is basically a crop rotation template as well. With some easy changes—the bed numbers could represent fields, months changed to seasons or years, and specific crops to crop families—you have the makings of a long-term crop rotation for your operation.
Similarly, for those of you that are certified organic or just want to be on top of recordkeeping, I have used a document like this to track the date and quantity of amendments applied to each field. It is nice to be able to look at things in the context of a calendar, as opposed to just notes on a page. Maybe organic recordkeeping should be left for another day, but I hope that this has you thinking of ways to better organize yourself.
This planting plan is great! Many of you may have taken one of the workshops at our annual Sustainable Agriculture Conference from the Wild Hope crew. They are incredibly detail oriented and organized in their recordkeeping.
The big takeaways from this plan for me are right here:
This is the crux of winter growing: How long does it take, and when will it be ready?
- 120 days to maturity for kale
- 90 days for bok choy
- 50 days for radishes
- 70 days for Hakurei (salad turnips)
Again, these numbers won’t work out exactly for you, but the days to maturity have more than doubled in some cases as opposed to being under optimal growing conditions with greater day lengths.
As we saw with Pam Dawling’s plan, an interesting piece is the difference in days to maturity of different successions of the same crop. Lettuce planted on 10/7 has 89 days to maturity, the 10/17 planting jumps to 107 days to maturity, and the 11/10 planting leads to 125 days to maturity. So the goal post is moving as you progress into the darkness of winter. This trend will begin to reverse as you move into January and February. As daylight increases, those numbers will begin their journey back to matching what’s printed on their seed packets. This is fascinating and difficult to manage!
Wild Hope, Pam Dawling, and surely countless others have been experimenting and, most importantly, keeping records so that the rest of us can have a good starting point. Big thanks to them for their work and willingness to share!
OTHER CONSIDERATIONS
Market Demands & Personal Sustainability
My early tomatoes were great, profitable, and worth the work. But, having high-quality greens at a time when the local food landscape is scarce can be very profitable as well. And, I think some, if not many, would argue that it’s more enjoyable to bundle up and work in a tunnel in January than it is to trellis endless rows of tomatoes when it’s 120 degrees in the tunnel come June.
But, don’t cut your kohlrabi at both ends (or burn your candle at both ends). Pushing all winter and not resetting for spring can have disastrous effects on your production the following year. Maybe you can slow down a little in your tunnel in the late summer to fall. Rest it. Grow a cover crop. Start a little later into the fall and winter with cool-season crops and see how it goes.
Interplanting & Companion Planting
There’s a lot of opportunity in companion planting and interplanting as winter holdovers cross paths with spring newbies, and summer survivors stretch into those first freezes.
One thing to be aware of is both crops’ moisture and temperature needs; they don’t always overlap. Those newly planted tomatoes between the holdout kale have different moisture, temperature, and fertility requirements. Once they are growing together, you’ll have to choose which one you want to favor at the expense of the other. Helpful hint: I (almost) always favor the newer crop! If fertility and moisture are not prioritized, a more established crop can easily suck up all the nutrition, or a more vigorous young plant can outcompete its older bedfellow for water.
Again, let’s look to our collective knowledge and those growers doing this work and start our experimentation with some level of understanding.
A good place to start is those short-season, quick crops that don’t need a lot of space and are light feeders. Things like radishes, salad turnips, baby greens (e.g., lettuce mix, arugula, kale, tatsoi, mizuna, tokyo bekana) can work well. Pam Dawling has done extensive work in this area and has some great recommendations for winter-hardy greens for your tunnel.
Download Pam’s Extend Your Growing Season into Colder Weather w/ High Tunnels Guide
Stay On-Schedule
When utilizing multiple successions and quick turnarounds, you need to have a strong market ready for your products or be prepared to abandon a planting and clear the bed to make way for the next round. Letting things linger too long may throw off the timing for the rest of the planting plan and affect your later offerings. And your typically bustling farmers market can slow to a crawl sometimes on those cold winter mornings. Having a home for all this delicious winter bounty before it’s sitting in your walk-in would be a good idea. It’s not an exact science, and you’ll never have exactly what you need at all times, so hopefully, you’ve connected with gleaners, food banks, or others in your community that can help those in need to put any surplus to good use and not waste those valuable calories and input costs.
Want More?
I’m available to continue this conversation with all of you in person! CFSA has high tunnel technical assistance available, as well as tons of high tunnel production resources online. Don’t hesitate to reach out.
I look forward to “digging” into all of this with you. So many puns; I’m sorry, I have a problem!
Good growing to ya!