Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
I had an interesting conversation with a Delmava-based crop consultant on the use of rainshelters for vegetable and fruit production. As the climate is expected to become wetter with more extreme rainfall events, losses of vegetable and fruits to excess rain will become more of a concern.
A rainshelter is a high tunnel structure that is used to cover plants during fruit formation and development. Multi-bay “European” style tunnels are most commonly used as rain shelters covering from ½ acre to several acres. Rain shelters are used extensively in high rainfall areas such as England to protect rainfall sensitive crops such as strawberries. Covers may be used for the whole season or just for the fruiting period.
Rainshelters are also used for tomatoes and other fruits such as cherries which are susceptible to cracking. Some fruits crack from absorbing water through the skin of the fruit when they are ripe or near ripe, others crack with excess water in the root zone, and there can be a combination of the two processes. Rainshelters control both types of fruit cracking. Rain shelters also reduce foliar wetting and rain splash and therefore can reduce fungal and bacterial diseases considerably if left on for the whole growing cycle.
While a high tunnel will serve as a rain shelter, less expensive low-tunnel structures can also be used that have a plastic cover over hoops from 2 to 6 feet tall.
Rain shelters have been shown to improve the quality of tomatoes throughout the growing season and can be a valuable tool to increased marketable fruits of high quality. They are also useful for fruit crops such as cherries, strawberries, brambles, grapes, and blueberries. Specialty melons prone to cracking will also benefit from the use of rainshelters.
Dwarf cherries being grown under a rain shelter.