Typical September and October frosts will not kill most Brassica species. During the past three years, in the southern third of the state for example, turnip growth ceased about the second week of November - when most producers were already into a hay feeding mode for the winter. During the exceptionally warm fall of 1999, leaf growth and root development continued into late December. Members of the Brassica family useful to sheep production include various types of turnips, rape, kale, tyfon and swedes. Varieties can be loosely categorized into forage, root or combination types.
Classification is dependent upon primary dry matter production site - the leaf or root or both.
Most Brassica species can be sown in the early spring or in the late summer or early fall - but timing of the seeding needs to be closely related to animal utilization of the product and the number of growing days needed prior to anticipated grazing. If your flock lambs in the winter, then a late-summer seeding can provide ewe feed during late September through December. If your flock lambs in the spring, an August seeding can be used to flush and winter ewes during November through February. Due to Michigan s wet, cool, fall climate and the availability of large amounts of late summer open ground following small grain and vegetable harvest, turnips for fall and winter grazing are an ideal crop for sheep producers. However, turnip tops, stockpiled for winter grazing are more vulnerable to weather damage, especially following a persistent hard freeze then are turnip roots.