Note to readers, attached is the complete final report for FNE04-503.
Our goal was to evaluate the performance of ten cut flower varieties in three kinds of tunnels using three different covers and two to three planting dates. We were seeking information that would help us match tunnel structures and covers in a way that would give us the highest quality cut flower crop.
Stock and lisianthus both performed better in the high tunnel than in any other structure. Most other cut flowers performed very well in the high tunnel, too, but they performed just as well in the less expensive structures. Even “second early” plantings of stock and lisianthus have performed just as well in the walk-in tunnel.
Unlike high tunnels, walk-in tunnels are not snow-bearing structures. In this area, they can only be used from late April through late November. The chief advantage of a walk-in tunnel is that it costs much less than a high tunnel. Temperatures within walk-in tunnels are fairly similar to those inside high tunnels, although temperature highs are slightly higher and lows are slightly lower in the walk-ins. Using breathable Typar to cover a walk-in tunnel creates a warmer (when un-vented) and less humid tunnel environment. With respect to most cut flowers, the walk-in tunnel covered with greenhouse plastic performed similarly to the high tunnel. Snapdragon, for example, performed very well in the walk-in tunnel when covered with greenhouse film. Bells of Ireland, Godetia, Asiatic lily, and China aster each performed very well in walk-in tunnels, regardless of the covering. The breathable cover is useful for cut flower production because it excludes insects, but it can create an environment that is too hot if not vented.
Low tunnels can be used from about May 1st through late November in this area. They are the least expensive structures for extending the season. Temperatures inside low tunnels covered with breathable materials are often cooler than those inside high tunnels. When plastics are used as low tunnel coverings, temperatures can become excessively hot. Even breathable fabrics can produce an environment that is too hot. As a rule, high tunnels and walk-in tunnels have produced better early-season cut flowers than low tunnels. Low tunnels remain a good choice for second early crops because they produce good later crops, and they do it very economically.