Brussels sprouts(Brassica oleracea var . gemmifera ) grow lento and are not tolerant of high temperatures , characteristics that make them a challenge to grow in climate with long , hot summer . They arebiennials — taking two class to complete their living round — and are able to come through the wintertime in the comparatively balmy climates of U.S. Department of Agriculture plant hardiness zones 7 to 9 . If leave behind to grow into their second time of year , the plants will flower and limit seed , but they are most often grow in the vegetable garden as annuals and pulled up after the crop of their sprout late in the season .
Seedlings
Brussels germinate seeds.html ) take temperatures above 50 degrees Fahrenheit to germinate , but in most areas , sow semen right away in the garden in early spring does n’t produce a serious harvest because the plant begins to get sprouts about the time that summertime heat eyeshade . More often , nurseryman part seeds indoors in the spring and set out transplant in the early- to mid - summer for a fall harvest time .
Five to six week after germination , seedlings are typically about 6 column inch high . They have round or gist - shaped , gray - green leaveswith a thick , waxy texture .
Mature Plant
Mature Brussels sprout plants aretall and upright , gain a summit of about 2 or 3 feet and a spread of about 2 foot . They have a thick , idle gray - green main stem from which grow the great , heavily vein leaves .
Sprout Development
Theedible sproutsdevelop from buds at the plant ’s leaf axils , the stop where the leaf ’s stem , called a leafstalk , meets the chief prow of the plant . The sprout themselves lie of clusters of small leaves that take form a tightly packed oral sex — like a mini bread — 1 to 2 inch in diam ; sprout that develop during warm conditions may formmore loosely .
Sprouts start to mature first at the bottom of the flora and ferment their way upward , and sprout are typically ready to glean within90 to 100 daysafter the plants are transplanted into the garden .
Flowering Stage
plant allow to winter will only flower and set come if they ’re exposed to temperatures below 45 degree Fahrenheit for a calendar month or two . When it does flower in the spring of its second year , the plant bear bunch of brightyellow , four - petaled flowerson a tall flush stalk at the top of the plant , and at this point any sprouts on the plant life will have an unpleasant flavor .
Cultivars
Among commercially develop Brussels sproutcultivars , some have been engender to reduce the species ' long grow season and increase its heating plant permissiveness . * * ' Bubbles , ' * * for example , matures after about 82 days and is especially tolerant of quick temperatures . * * ' Jade Cross E ' * * and * * ' Oliver ' * * are notable for their sprout , which are heavy and comparatively easy to remove from the industrial plant . * * ' Rubine ' * * is an strange variety that produces flushed sprout but is very slow - growing , taking about 105 Clarence Shepard Day Jr. to mature .
