Brassicas

Brassicas in garden (photo Yvette Henson)

by Yvette Henson

I just planted my brassica seeds in flats to plant out into the garden when it is time.  Brassicas are plants in the Brassicaceae family, also known as cruciferous or cole crops.  Plants in this family that are grown for eating include cabbage, kale, broccoli, cauliflower, mustard, radishes, turnips, and more.  As vegetables, they are rich in anti-cancer compounds, one of which is free glutamine.  Brassicas are also high in other many other nutrients.

Brassicas are cool-season crops.  Although some varieties can take longer to mature, they can better survive temperatures below freezing.  We can plant them before the last spring frost and/or later in the summer so they mature when temperatures are cooler (which will improve their flavor and quality).  Cool-season crops generally do very well in our mountain communities where we have lower day and nighttime temperatures.  They can grow well in the open but growing under cover gives the advantage of an extended harvest (earlier and later), cooling in the summer, less evaporation from the soil and protection from cabbage worms, etc.

Brassicas in garden (photo credit Yvette Henson)

Brassicas aren’t too picky about soil - some of them even prefer clay soil.  They do require fertilization (pre-planting and every 3 weeks through harvest), and need water most when establishing and when edible parts are maturing.  Uneven watering and high temperatures may cause heading-type brassicas to split or bolt.  Many disease problems can be reduced if grown on 4-5 year rotation with non-cole crops. The most common insect pests are cabbage worms, aphids, and flea beetles.  These pests are best managed by reducing stress on the plants, covering them with row cover or timing the planting to avoid a particular pest. 

All the varieties I will recommend in this article are open pollinated (OP).  That means that you can plant extra for seed production.  If you provide proper growing conditions, isolation distances and save the best for seed, replant and repeat, you should eventually get a better strain adapted to your local conditions.

Radishes  (photo Baker Creek Seeds)

Radishes (Raphanus sativus) are a good digestive.  Radish roots can be eaten fresh, be pickled or roasted.  There are also radishes cultivated for their edible leaves and seed pods (Raphanus sativus subsp. caudatus).  Radishes are probably the easiest Brassica to grow.  Be sure you know if you have spring radishes or fall radishes so that you plant them in the correct season.  Most spring radishes mature in a short time (30 days +) but generally fall radishes take longer to mature.  If your season is really short you can plant both types in the late winter and spring, but if you have warmer summer days you will want to plant fall radishes later.  Fall radishes often store well. My favorite spring radish so far is ‘Early Yellow Turnip-rooted’.  Yellow radishes withstand heat better than reds.  My favorite fall radish is ‘Watermelon Radish’ (60 days).

Kales (2 different Brassica spp.) have a high mineral content and are good cleansers.  They also contain vitamins A & K and potassium.  They are easy to grow and can yield a lot of greens over time in a small area.  Kale can be direct seeded in the garden 3-5 weeks before the last frost date, or 6-8 weeks before first frost.  You can start harvesting young leaves as early as 40 days and it can be harvested several weeks after the last frost.  ‘Red Russian’ is a Siberian kale (Brassica napus), the classic kale with tender leaves that makes great massaged-kale salad; dinosaur kale (Brassica oleacea) is great in soup and for kale chips; and a beautiful burgundy-leaved curly kale (Brassica oleacea) is ‘Baltic Red’ which is edible and ornamental! 

Early Jersey Wakefield Cabbage (photo Southern Exposure Seed)

Cabbage (Brassica oleracea var. capitata) contains chlorine and sulphur which help cleanse stomach and intestines, and cabbage juice is good for stomach ulcers.  They are relatively easy to grow but they don’t compete well with weeds or deep cultivation. They do best when planted as young plants directly in the garden.  If planting is timed so that heads are forming when temperatures are cool they will be denser and of better quality.  They are most susceptible to frost damage when heading up, but there are cabbage varieties classified as winter cabbages that can withstand frost.  These types can often be stored for several months in the winter.  Two of my favorite varieties of cabbage are ‘Early Jersey Wakefield’ and ‘Mammoth Red Rock’.  ‘EJW’ is an early (60-75 days) cabbage with a conical head and mild, sweet flavor, and it doesn’t take up too much room in the garden.   'MRR’ matures a little later (100 days), it has a round flat head with purple tinged leaves and stores well. It makes an excellent semi-fermented ‘kraut’.  Purple cabbages seem to experience less aphid pressure.

Mammoth Red Rock Cabbage (photo credit Yvette Henson)

Nutribud Broccoli (photo Adaptive Seeds)

Broccoli (Brassica oleracea var. italica) can be a little more difficult to grow than cabbages.  They do best when planted out as young plants about the time of last frost (earlier if under cover).  Our favorite broccoli is ‘Nutribud’ (80 days).  It contains higher than average amounts of free glutamine.  It forms a beautiful head followed by side shoots.  We prefer the side shoots rather than the heads - they are more tender and continue producing until winter kill. 

Cauliflower can be difficult to grow.  It is sensitive to handling, temperature extremes and sun scald on heads.  A reliable variety that is easier-to-grow is ‘Macerata’ (70-80 days), it forms tasty lime-green heads.

'Macerata' Cauliflower (photo Baker Creek Seeds)

Please share your successes and lessons learned growing Brassicas.  What are your favorite varieties?

Yvette Henson is the Director and Agent at the Colorado State University Extension in San Miguel and West Montrose Counties.