Long season brassicas consists of Kale and Swede and they can produce more tonnage than short seasons but require more time and nutrients to do so. These aren’t near as common as short season brassicas in the food plotting world. Long season brassicas are more susceptible to grass problems but that can be controlled with clethodim (Select or Arrow) at 6-8 ounces per acre along with crop oil and Dual II Magnum is supposed to be safe for pre-emergence weed control in brassicas as well.
Varieties of kale differ markedly in rate of establishment, stem development, time required to reach maturity, and in winter hardiness. The stem-less type kale (e.g. Premier) has a faster rate of establishment than varieties which produce stems. Crop height of the stem-less type is approximately 25 inches, whereas that of marrow stem kale is 60 inches with primary stems often 2 inches in diameter. Stem-less kale attains maturity in approximately 90 days, allowing two crops/year, whereas varieties that develop stems require 150 to 180 days to attain maximum production. Premier has consistently survived winters in central Pennsylvania, whereas other varieties of kale usually are winter-killed in December. Pay attention to the maturity dates on whatever variety of brassica you plant and get them in the ground so they can mature before the first frost.
Like turnips, Swedes produce a large edible root. Yields are higher than those of turnip, but they grow slower and require 150 to 180 days to reach maximum production. Swedes usually produce a short stem (neck), but can have stems 2 1/2 feet long when grown with tall crops which shade the swede. Unfortunately, stem elongation is at the expense of root development. The variety Calder was found to be cold hardy in central Pennsylvania and thus ideal for stockpiling and late fall or early winter grazing.