I'm always looking for the most recent techniques to help protect our plants from deer and other critters. Deer browsing our shrubs, vegetables, and flowers is a constant source of angst for home owners. Fencing deer out of your yard is often not practical for a suburban homeowner, so repellent sprays are really the next best option.
Recent research at the Connecticut Agricultural Research Station, reported by Connecticut Gardener magazine, highlights the best repellents. Essential oil based repellents, containing oils such as mint, thyme or pepper, often evaporate quickly. Odor based sprays, such as those containing rotten eggs or blood meal, are more effective, but eventually wash off plants after about 5 weeks. In their research, the best deer repellent sprays were fat based. Fat based sprays don't smell bad to humans, don't need reapplying after rains and gave plants months of protection.
Fat-based repellent sprays were discovered in Austria when farmers noticed that deer avoided plants that had raw sheep’s wool hanging on them. Raw sheep's wool has lanolin-based fats that repel deer. Lanolin is a byproduct of wool processing and is safe for people, wildlife and the environment. While their research showed three months of protection from lanolin-based sprays, these commercial products, such as Trico, are very expensive.
A less expensive home remedy alternative that proved as effective as lanolin-based sprays is milk fat. Mixing Half & Half with equal parts water in a sprayer worked as well as the lanolin sprays.
