Extending the vegetable growing season with low cost quick hoops

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2010: $6,000.00
Projected End Date: 12/31/2013
Region: North Central
State: Missouri
Project Coordinator:
Curtis Millsap
Millsap Farm

Annual Reports

Information Products


  • Vegetables: beets, carrots, greens (leafy), greens (lettuces), radishes (culinary)


  • Crop Production: high tunnels or hoop houses

    Proposal summary:

    Local food producers are in an enviable position at this time in history; every newspaper or radio station, or T.V. station seems to have some piece about the importance of local food, and customers are getting to farmers markets, farm stands, and local food stores in record numbers. Unfortunately, most producers in the midwest stop growing after the first frost, and don't have produce for about 5-6 months out of the year. Similarly, there is a two to three month period in the summer when it is too hot outside to produce lettuce, as it gets bitter and bolts before it reaches harvest size. This leaves eaters with a quandary; how to eat local year-round.

    High tunnels and climate controlled greenhouses offer options for growers to extend the season, but usually with a high price tag, both for construction and on-going expenses. High tunnels may be able to be constructed for around $2-$5 per square foot, while heated greenhouses are usually more in the range of $5-10 per square foot. This high cost makes it necessary to grow very high value crops with long harvest windows in these structures, like salad greens, tomatoes, spinach, and cucumbers. Unfortunately, this often means that lower profit, slower growing, or single-harvest staple crops, like green onions, carrots, beets, radishes, potatoes, etc., are not worth the expense of covering with a high tunnel, and so they are not available to local markets after the outside weather gets too bad to keep them in the ground. Additionally, the high cost of a high tunnel or greenhouse is often a deterrent to new growers, or experienced growers interested in extending the season, either because they simply don't have the capital to spend up front, or because they are unwilling to borrow money in the hopes of earning it back in a timely manner. So the problem, to put it simply, is that growers need lower cost field-scale season extension strategies, so they can supply local food to eaters year-round.

    On our farm we have begun to explore the possibilities of temporary low hoops with light coverings, sometimes referred to as quick hoops. These hoops are bent out of 10' galvanized electrical conduit (EMT), bent into 6' diameter half circles, stuck into the ground 6"-12" on each side, then covered with either floating row cover or plastic, which is weighted down on the edges. The first place we encountered the practice was in The Winter Harvest Handbook, by Elliot Coleman. This fall we've installed about 1,600 linear feet of quick hoops, covering a 6' wide double-bed of vegetables, for about $1,000 in materials, and $300 in labor. This means we've covered 9,600 square feet of growing space for under $ 0.15 per square foot. Currently, at the end of November, after several frosts into the upper teens, we are harvesting bok choy, beets, carrots, arugula, lettuce, spinach, green onions, kale, mizuna, spinach, and two types of turnips from under our quick hoops.

    We think the potential of this simple innovation is tremendous, and needs to be explored further. The problem is there is minimal information on the best way to build, maintain, or cover these temporary structures, especially on a field scale. We can see that this could be the key to low-cost, low-risk season extension, both in the winter and spring with various frost covers, and in the summer with shade cloth to shelter delicate head lettuce and baby lettuce from intense heat, but there is very little information on the best materials and practices. We are currently using the lightest weight row cover available because of expense, our concerns about light transmission in the darkest time of the year, and the potential for overheating on those occasional warm and sunny days in November and December. However, we wonder if other weights of covers might work better, and we would like to determine what the "sweet spot" is where optimal light transmission and warmth retention intersect with economics.

    We propose to use 12 different 200' beds to trial six different types of winter covering, including no cover, three different thicknesses of row cover, greenhouse plastic, and greenhouse plastic with row cover under it. We'll plant beets, spinach, carrots, baby lettuce, and kale in each bed on the same date, approximately the first of September, covering them before the first hard frost, and use wireless data loggers in combination with a laptop computer to record and graph soil and air temperatures in each trial plot throughout the winter. Additionally, we'll note date of first harvest, quantities harvested each week, frequency of harvest, degree of frost damage to each quick hoop on a weekly basis, and overall mortality of plants under the various treatments.

    In the summer we'll trial 6 200' beds of lettuce, planting several varieties or head lettuce and baby lettuce under three different thicknesses of shade cloth, supported on the same quick hoops. For the summer crops we'll record dates of harvest, overall yields per treatment, and degree of heat damage or bitterness or bolting. We will keep track of the cost of each different treatment, and compare that to the overall benefit to the crops. Our goal is to determine which cover or combination of covers is most beneficial and economical toward the goal of extending the growing season in challenging growing conditions.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.