Supplemental Heat for Winter Greens Production: What's the Cost?
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture

There seems to be little agreement among winter greens growers regarding the true costs and potential value of using supplemental heat all winter. With support from the Northeast Sustainable Agriculture Research and Education program (NE SARE) and the generous cooperation of the Poughkeepsie Farm Project (PFP), we tried to start gathering some data to add to the high tunnel heating debate. We tracked yield, soil nitrate availability, total nitrogen uptake, propane use, and soil temperature all winter in the two identical side-by-side 42'x196' double layer inflated poly Harnois high tunnels with one tunnel set to 33 degrees ambient air temperature and the other set to 40.
The data from the trial is still being analyzed, but here are a few key results that have emerged:
- Maintaining adequate soil moisture and, ideally, living roots in the high tunnel before planting is necessary to preserve the soil microbial community that makes nitrogen available for plant uptake.
- Soil nitrate levels were not significantly or consistently different between the two temperatures; however, total nitrogen uptake in the warmer tunnel was higher for curly kale, spinach, and especially for Salanova lettuce.
- The warmer tunnel yielded three harvests in the same time that the cooler tunnel yielded only two.
- It took 979 gallons of propane to heat the tunnel to 33 degrees from November through March. It took 2.1 times as much propane to add the extra 7 degrees to reach 40 over the same period.
- Fertilizing to 70 pounds/acre of nitrogen in September provided sufficient nitrogen to kale, spinach, and Salanova until mid-February.
- Targeted early spring fertigations with soluble Chilean nitrate carried those crops to maturity in early April
A big thanks to the great crew at PFP for all of the help tracking yield! Going forward, a group of vegetable specialists with Cornell Cooperative Extension hopes to continue to investigate fertility management in winter high tunnels generally and specifically the interplay between supplemental heating and nitrogen. If you are interested in collaborating, please reach out to Ethan at eg572@cornell.edu.
This article is from the April 26, 2018 edition of ENYCHP Vegetable News. To read the full newsletter, CLICK HERE.


Upcoming Events
Cover Crop Field Meeting

October 21, 2025 : Cover Crop Field Meeting
Willsboro, NY
Thinking about upping your farm's cover cropping game? New technology for seeding and crop tracking, research-driven recommendations for high tunnel cover cropping, cold tolerant varieties for North Country climates, and farmer expertise will be shared at this field event.
New York State Agritourism Conference
November 10 - November 11, 2025 : New York State Agritourism Conference
Saratoga Springs, NY
The first-ever New York State Agritourism Conference, hosted by the CCE Agritourism Program Work Team, is designed to support farms in growing successful visitor experiences. This statewide gathering will feature expert-led sessions, peer networking, and practical tools to help farms expand direct sales, education, hospitality, and entertainment offerings.
Date:
- November 10: A full day of educational sessions targeted at beginning or experienced agritourism operators.
- November 11: A half-day, interactive networking session with fellow attendees.
ASL 104sp Seleccion y organizacion del personal (Staffing and Organizing Your Team) taught in Spanish
November 12, 2025 : ASL 104sp Selección y organización del personal (Staffing and Organizing Your Team) in Spanish
ASL104-SP: Selección y organización del personal (Staffing and Organizing Your Team - impartido en español) ¡Inscripciones abiertas!
En este curso identificamos cómo escribir descripciones de puestos disponibles en el trabajo para atraer a los mejores candidatos. Aprenderá a encontrar empleados con un perfil deseado, cómo entrevistar y seleccionar a las personas adecuadas. Descubrirá cómo completar la documentación de nuevos empleados, la autorización de empleo y la contratación de personal (on-boarding): es decir, cómo efectivamente incorporar nuevos empleados al rancho en una manera exitosa y productiva.
Los temas incluyen:
- Convertirse en un lugar de trabajar preferido
- Planear cuántos y qué trabajadores se necesitan
- Diseñar descripciones de trabajos para un mejor reclutamiento
- Cómo evitar favoritismos y discriminación
- Cómo buscar y entrevistar los nuevos trabajadores
- Cómo decidir a quién contratar
- Y cómo dar una buena bienvenida al nuevo trabajador
Inicio del curso: miércoles, 12 de noviembre de 2025
Discusiones en vivo por Zoom: Cada martes 18 de noviembre - 23 de diciembre, de 1:00 a 2:00 p.m. (hora del Este)