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COVER CROPPING FOR POLLINATORS AND BENEFICIAL INSECTS

cover crops for pollinators. Grass cover crops do not pro- A pollinator-oriented cocktail may include a mix of plants
vide nectar and their pollen typically has lower protein con- that have different strengths and which flower at different
tent than the pollen of broadleaf plants, making them only times. Buckwheat, rapeseed, lupines, phacelia, sunn hemp,
marginally attractive to bees. A flowering plant/grass blend cowpeas, partridge pea, sunflowers, and many clovers are
may be an ideal solution in situations where a grass crop all cover crops that are also beloved by bees and benefi-
is needed to achieve other management priorities, such cial insects. Stacking these pollinator plants in one field
as preventing nutrient leaching. You have more flexibility can lengthen the bloom period. For example, if rapeseed
when selecting plants in support of predator and parasitoid blooms in early spring and is harvested in May or June, then
insects for pest management, with certain grass cover crops it can be followed by the late-summer blooming sunflower,
supporting alternate prey (such as aphids) to help sustain which can then be over-seeded with a winter legume/small
the beneficial insects when cash crops are absent. Avoid grain mix. The rapeseed serves to manage nematodes, the
cover crops that serve as alternate host plants for crop dis- sunflowers mine nutrients and bring them to the surface,
eases and those that support large numbers of crop pests. while the legume/grain mix adds nitrogen and prevents
An alternate host is another species, different from the cash winter erosion. This is just one path using an all-pollinator
crop, which serves as a reservoir for the pest or is necessary rotation for season-long flowers. All of these plants except
for the pest to complete its life cycle. For example, if you are the small grain have flowers highly preferred by pollinators
growing a brassica vegetable crop, do not cover crop with and other beneficial insects. Additionally, some plants like
another brassica, as it would support similar pests. How- cowpeas and sunflowers also have extra-floral nectaries—
ever, cover crops that support low levels of crop pests may or nectar-producing glands at leaf stems—which attract
be valuable in some cases, as they can provide a consistent and support beneficial insects.
food source for beneficial predators. This diversity can really pay off. Using a SARE grant, a re-

searcher in Florida found significant differences in wild bee
abundance and diversity based upon the number of crops
present on a farm. At one end of the spectrum, the farm
with the fewest number of bees (5 species) grew only two
crops and mowed directly up to the field edges. The farm
with the greatest abundance of bees (14 species) grew nine
crop species and maintained open, unmowed buffer areas
around the farm. Multi-species cover crop mixes are a rela-
tively simple way to expand plant diversity on a farm, with
benefits to bee abundance and diversity.
This is an excerpt from an excellent publication from SARE
entitled “Cover Cropping for Pollinators and Beneficial In-
sects”. If you are interested in this topic, we encourage you to
download the entire 16 page bulletin from www.sare.org.
Diverse cover crop cocktails have synergy and they general-
ly work better than each single species could alone. In fact,
a planting of legumes and grasses can result in an overall
increase in available nitrogen. Legumes build up soil ni-
trogen quickly, but their residue also decomposes quickly,
releasing nutrients. A small grain does not add soil nitro-
gen, but it is an excellent nutrient scavenger. Additionally,
its residue decays over a longer period of time, providing
a slow-release mechanism for soil nutrients. Small grains
are also useful for controlling erosion, preventing nutrient
leaching and suppressing winter weeds. Mixing the fertil-
izing effects of the flowering legume with the soil-building
small grain can be a winning combination for winter cover.

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