The Appin Turnip is bred for it's leafy crown, mostly as a forage for cattle, other livestock, and deer plots.  As a cover crop, they produce a heavy cover, and because of a quick maturity, are valuable as a cover between the harvest of a crop, and the planting of later crops, such as spring and fall crops.

Unlike other turnips, the Appin Turnip grows it's bulb mostly in the ground.  This allows it to grow leafy forage from it's multiple crowns to produce repeatedly, and giving a possible 4 regrowths of grazing forage.

I'm offering 1/6 an ounce (5 grams), or around 1250 seeds, enough to cover 96 square feet, or 6 square foot gardens, if full turnip coverage is desired, 240 square feet, or 15 square foot gardens, if mixed with other cover crops.

Turnips, have been grown and eaten for more than 4000 years, probably starting in Europe.  Archeological records show turnips grown in India 1500 years BCE for oil.  Wild relatives are found all over western Asia, and eastern Europe, so it's thought the origin of the plant is in this region.  The bulbous root and leafy tops are both edible, giving rise to many cultivars focused on the kind of food grown.  The Appin turnip is a forage turnip.  It was bred for planting in pastures and growing large leafy crowns so browsers like Deer, cattle and other grazers would have forage in the colder parts of the year.  The roots and large crown are helpful in scavenging nutrients and shading the soil to choke out weeds.  The bulbous taproot growing mostly in the ground would then hold those nutrients until they are killed and decompose in the beds, releasing them back to the soil.

Turnips are somewhat shade tolerant, so can be used in cover cropping situations that would allow the first crop to finish while the turnips get started.  While most turnips grow their bulb above the ground, the Appin turnip tends to grow it's bulb in the ground, allowing it to remain warm enough to continue putting it's energy into the crown. Turnips are cold tolerant and will often overwinter without any freeze-kill.  For that reason, they would have to be manually killed in the spring when used as a cover crop.

Turnips, Radishes, and Mustards are all members of the Brassica family, and are all used as a cover to build soils and deter weeds.  Tillage Radishes tend to freeze out in the middle of winter, so are useful in storing nutrients, and then held until the ground warms.  Turnips are different by not dying in the cold, but continue to hold that nutrition for longer, until manually killed.

Appin turnips should be broadcast over the bed, and compost or other media raked over the seed to a depth of around 1/2 inch (13 mm).  Maximum depth of planting is 1 inch (25 mm), to give the seed a chance to sprout in dry soils.  The plants should develop easily in garden soils, without further amendment.

Turnips, in general, don't germinate well in cold soil.  Seeding should be delayed until the soil is above 50°F (10°C).  If plastic is placed over a garden bed, the sun's rays will pass through, collect under the plastic, and warm the soil, a process called "Solarization."  In the North, turnips are best planted at the end of July, or start of August for a winter cover.  In the south, the turnips can be planted in late summer or early fall to overwinter.  In my experience, the turnips are much more tasty to flea beetles, and tend to get wiped out if planted too early.

Appin turnips are fairly drought resistant, due to the large taproot.  Young plants aren't very good at handling extended dry periods though.  The turnip crowns are tall and dense, so will shade the soil and deflect rain to help avoid erosion.  Because of this density, Appin Turnips will shade out shorter crops.  They can be safely planted under Tomatoes, Corn, or other tall crops, and will achieve maturity while other crops finish.