Mustard greens, a leafy brassica, are highly susceptible to browsing damage from deer, especially when other food sources become scarce. The presence of deer in residential and agricultural areas has increased, making the protection of vegetable gardens a common challenge for growers. While mustard greens are not their only food source, deer will readily consume them, and the damage can quickly decimate a crop. Understanding the factors that make these greens attractive to deer is the first step in developing an effective protection strategy.
The Deer’s Diet: Are Mustard Greens a Favorite?
Mustard greens are part of the Brassica family, and deer are generally attracted to the tender, high-moisture content of leafy vegetables. The palatability of mustard greens stems from their tender texture and nutritional value, which deer seek out. They particularly favor the new, fresh growth of these plants, often consuming the entire leaf blade.
The characteristic sharp, peppery flavor of mustard greens comes from compounds called glucosinolates. Deer are sometimes deterred by this pungent taste when the plant is young and the flavor is strongest. However, the concentration of these compounds often decreases after a light frost, converting starches into sugars and making the greens sweeter and more appealing to deer. Consumption of mustard greens and other brassicas generally increases during the late summer and fall when natural forage quality declines and deer are seeking nutrient-dense food sources to prepare for winter.
Identifying Deer Damage vs. Other Pests
Distinguishing the culprit behind garden damage is necessary for selecting the right control method. Deer browsing is characterized by a ragged, torn appearance on the leaves and stems. This specific type of damage is a result of deer lacking upper incisor teeth; they press the lower incisors against a hard dental pad on the upper jaw and tear the plant material rather than making a clean cut.
Deer damage typically occurs from ground level up to six feet, often creating a noticeable browse line on taller plants. Rabbits, in contrast, possess sharp incisors that create a clean, 45-degree cut, and their feeding is usually confined to the lower parts of the plant, generally within two feet of the ground. Damage from slugs and snails is distinct, leaving irregular holes and often a telltale slimy trail on the foliage. Identifying the torn edges and height of the damage is the surest way to confirm deer as the primary pest.
Effective Strategies for Protecting Your Crop
Protecting a mustard green crop requires a combination of methods, as deer are persistent and adaptable. The most reliable method for complete exclusion is the use of physical barriers.
Physical Barriers
A permanent fence must be at least eight feet tall to prevent deer from jumping over it, as they can clear obstacles up to seven feet high. For smaller garden plots, an opaque fence is sometimes effective even if slightly shorter, as deer are hesitant to jump over a barrier when they cannot see where they will land. Another effective physical barrier is a double-row fence, which utilizes two parallel, lower fences spaced about five feet apart. The depth perception challenge discourages the deer from attempting both jumps. For temporary protection of a small crop, a simple polypropylene mesh netting or row cover draped over hoops can deter casual browsing.
Repellents and Deterrents
In addition to physical barriers, repellents can provide a secondary layer of protection. Repellents work by using taste, odor, or fear to discourage feeding. Taste-based sprays often contain putrescent egg solids or capsaicin, making the treated foliage unpalatable. Odor-based options use strong scents like garlic, mint, or predator urine to make the area undesirable.
For maximum effectiveness, repellents must be rotated and reapplied frequently, especially after rain or when new plant growth appears. Motion-activated sprinklers or auditory devices can also be used as temporary deterrents, as deer are easily startled by sudden movement or noise. A layered approach that combines a robust physical barrier with the strategic rotation and reapplication of scent and taste repellents is the most successful strategy for protecting mustard greens from deer damage.