Farming with Low Tunnels
Farming With Low Tunnels Allow Early Spring Planting
Farms based in Zone 9 of the US Hardiness Zone Map can produce crops all through the year due to low hard frosts during winter. However, even in regions with hard frosts throughout the winter can use a seasonal low tunnel to overwinter crops. Low tunnels allow farmers to have an earlier spring crop by creating a warmer microclimate that allows many spring farms to be planted in late fall.
Farming with low tunnels uses inexpensive structures that are easy to assemble and disassemble. This allows them to be easily moved to different crops and locations. They are the smaller, less expensive and temporary version of a greenhouse. Unlike a greenhouse, they can be moved which increases soil health and optimizes space for a small-scale farm. They also are sustainable because they increase yields, water and nutrient efficiency, and enhance growth. They are comprised of either metal hoops or PVC pipes for structure and plastic, spun-bonded fabric, or insect nets for coverage, and sand bags or some weight to hold down the covering.
The row cover is important based on location. If there is possible chance of snow, plastic will create a warmer environment that is also stronger to hold snow and maintain intact against wind. However, plastic may be too warm in some regions and cause condensation that could lead to decay, therefore, a spun-bonded fabric would be a better option. Spun-bonded fabrics are conducive for air flow, if plastic is used, it’s necessary to open the sides of the row cover for ventilation on warmer days after the winter solstice.
Low tunnels built with string or rope on either side can tie down the cover to the stakes; but allow easy access to inside of the tunnel to harvest.
Low Tunnels Protect Newly Planted Crops From Pests and Weather
Once bed is prepped, seeded or transplanted crops and then as soon as possible put up the low tunnel to protect newly planted crops from pests and weather. One of the benefits of the cover being plastic or fabric, allows the sides to be easily moveable, therefore allowing maintenance within tunnel, such as wedding or repairing irrigation. Additionally, by using weights to hold down row cover along with rope ties, allows the cover to be easily lifted. Another weight could be by shoveling clumps of dirt over the row cover to weight it down.
Another way to warm up the soil in conjunction with the low tunnels, is to place jugs of water in the soil. Before planting crops, dig a large enough whole for a gallon jug to place into bed. Since water has a high heat capacity, the heat will release during the night and keep the soil warm, thus decreasing chances of frost and enhancing vegetative growth. This is a labor-intensive process and thus may be better for small plots of high value crops to extend their growing season.
During late fall and early spring, cool season crops that can be planted in a low tunnel include: kale, kohlrabi, broccoli, lettuce, spinach, chard, onions, and beets. Cool season cut flower include: anemone, ranunculus, chrysanthemums, and daffodils.
Farming with low tunnels is a great way to protect crops from harsh winter weather and produce greater yields. They are great alternative to greenhouses since they are not permanent and can extend growing seasons and allow farmers to provide a more continuous supply of vegetables.
About Margaret Cooper
Margaret is a student studying environmental science management with a passion for conservation, ecology, and sustainability. She is a gardener and floriculturist at her university’s Student Farm where she enjoys creating a working landscape that provides both food and ecological habitat. She loves going into the garden and creating recipes on the spot from farm-fresh food.
Vandenlinden, Colleen. “Tips for Growing in Low Tunnels.” The Spruce, TheSpruce,
“Quick Hoops Low Tunnels | Set-up & Management with Eliot Coleman.” Greenhouse Bell
Pepper Production Guide | Tech Sheet (PDF), www.johnnyseeds.com/growers-library/vegetables/managequickhoops.html.