How can Midwestern growers make the most of winter high tunnel real estate for winter salad mixes?

View the project report

Commodities

• Vegetables: greens (leafy), greens (lettuces)

Practices

• Crop Production: continuous cropping, greenhouses, high tunnels or hoop houses

Optimizing production in winter high tunnels relies on careful selection of crops, because winter plant growth is so slow and limited. Every year, we consider winter market demand and plant crops that we know will grow well, but we wish we had better data on the relative yields of our various potential salad mix ingredients so that we could make the most informed decisions about what to plant and how to use our precious tunnel space for the best winter yields. 

Winter vegetable production provides growers with great opportunities to enter untapped markets, to distinguish themselves with niche products, and to spread their income through the year. At the winter Worthington Farmers Market, the largest farmers market in Columbus, we regularly sell out of our produce early in the market, suggesting that the market could accommodate additional growers. Still, Midwestern winter growers, especially as they’re starting out, may struggle to find information that will allow them to optimize their winter salad mix production. Research has confirmed that babyleaf brassicas and lettuce are among the top choices for generating income with winter growing, but with so many choices on the market, it’s hard to know which varieties generate the best returns. 

Solution:

We will trial 8 varieties of cold tolerant babyleaf brassicas, 2 arugulas, and 4 varieties of lettuce for salad mix by seeding each of these crops in our unheated high tunnels in 2.5’ x 10’ blocks on three different dates in September, October, and November 2023. For each planting date, all trial varieties will be planted into the same tunnel. We will choose trial varieties based on past experience, and input from other growers. We’ll also choose varieties that have varying colors, textures, and shapes to create an appealing salad mix for customers. We’ve found that planting single varieties of brassicas and lettuce rather than mixes, and mixing the varieties post-harvest, allows for better yields and control for winter growing. Different varieties bolt at different times and some get freeze damage or disease while others remain unaffected. Our goal here is to find 4-6 varieties for optimal winter salad mix yields. 

To prepare beds for planting, we will broadfork, use a power harrow or tilther, apply organic fertilizer or compost as needed according to our soil tests, then direct seed the crops into our high tunnel beds with a Jang JP-5 seeder, seeding 10 rows per 2.5’ wide bed for all crops. After seeding, beds will be irrigated with drip tape or micro sprinklers and covered with row cover to aid germination. Row cover will be removed after germination, and left off except during periods of <20 degree F weather. Below 10 degrees F, we will cover the crops with two layers of row cover. Most of our tunnels have automatic louvre vents at the peak of each endwall. We will also roll up tunnel sides to vent the tunnels when the tunnel temperatures reach >80F 

We hope to get as many cuts as possible off of each planting, so crops will always be harvested above the growing tip for cut-and-come-again harvests. Crops will be harvested with the Farmer’s Friend Quick-Cut Greens Harvester (https://www.farmersfriend.com/quick-cut-greens-harvester). We will track the days to harvest for each crop, the number of harvests we’re able to get throughout the winter season, the marketable yield (mass) per harvest, and the overall total mass we harvested per crop over the winter. Every week, we will also record any noticeable differences in crop health by taking photos and notes, looking for differences in disease, pest pressure, and cold damage. We will also track the overall sales of lettuce to identify any trends in the market demand for varieties. 

Objectives:

1. Evaluate the relative yields of 8 babyleaf brassicas, 2 arugulas, and 4 lettuce varieties planted in high tunnels on 3 different planting dates for winter harvests. 
2. Identify which 4-6 of these crops give the best yields for winter salad mix production.
3. Share findings through a field day, quarterly Community Growers Network trainings, our website and social media, and a conference presentation