What are the best winter cover crops
for home gardens in Pennsylvania? When should they be planted? What
should be done in the spring to kill them or till them in?
A. Cover crops are grown to protect the soil from erosion,
and to be cut back and tilled into the soil in spring to increase
its organic matter and nutrient content. They also help stimulate
soil microbial activity, shade out germinating weed seeds, and help
loosen compacted soil as their roots grow. Winter rye is the most
commonly grown winter cover crop in our area because it is cold
tolerant and can be sown as late as mid-October, which gives
gardeners time harvest annual vegetables and remove spent annual
flowers prior to planting.
Cover Crop Growth
It is a winter annual grass
that will continue to grow until temperatures drop to about 40
degrees and resume growth when temperatures warm in spring.
Winter rye germinates quickly, and tolerates wet or dry
conditions, low fertility, and acid soils.
It secretes a substance that inhibits the growth of many weeds
and other plants, so it is important to mow it down and till it
in about four weeks prior to planting vegetables or flowers next
spring. All raw organic matter can tie up available soil
nitrogen as it decomposes and cause a temporary nitrogen
deficiency in crops, so working it into the soil early enough
avoids that problem as well. Winter rye produces a dense root
system and lush foliage, so it can be difficult to till under.
It helps to mow it short prior to trying to till it in. It may
be easier to compost the clippings for later application to
garden beds, and till in the crowns and roots alone.
Legumes as Cover Crops
Certain legumes are often used as cover crops, but really
provide the most benefit if you plant them in spring and allow
them to grow all summer, which can take too much valuable space
in a home garden. Legumes are plants that have the unique
ability to fix nitrogen from the air in association with soil bacnsive root systems
and are a good choice to break up hard, compacted clay soils.
Their best use in home gardens may be to start new beds in
places where the soil is less-than-ideal. Strip off the sod,
plant a cover crop of legumes, and allow them to grow for a
season before working them into the soil. Plteria, and they
return that nitrogen when they are cut back and tilled into the
soil. They also have exteant the desired
crops next year. Legumes used for cover crops include clovers,
hairy vetch, and alfalfa. Be sure to cut them back before they
go to seed, or some will make a nuisance of themselves.
Planting a cover crop
To plant a winter rye cover crop, remove spent annual vegetables
and flowers from the garden. Till up the soil to prepare a good
seedbed, then broadcast the seed at two to two-and-a-half pounds
per thousand square feet. Rake it in lightly and water to start
the germination process.
Composting for the garden
Ash tree damage