Brussel's Sprouts form right at the base of each leaf. If the plants are left alone the sprouts at the bottom mature first while the plant continues to grow taller and produce smaller sprouts up the stem, clear to the tippy-top. You will get plenty of sprouts without doing ANYTHING to the plant. However, most of them will be disappointingly small. If you want larger sprouts I suggest the following:
1. As sprouts begin to form at the base of the leaves, remove some of the lowest leaves every other week or so by either snapping them off sideways or cutting them off with a knife. Removing excess leaves channels more energy into growing sprouts rather than leaves.
However, be sure not to remove more than 1/3 of the leaves at any one time or the plant will become stressed and production could actually be negatively affected.
Topping plants stops them from growing taller and producing more sprouts, and lets the plant concentrate on plumping up the sprouts that are already on the plant. Interestingly enough, topping the plants seem to cause the upper sprouts to get bigger than the lower sprouts!
If you do these two things you will be amazed at how big your sprouts will get! But don't let them get too big before you harvest them... or they could get loose and tough on you if you're not careful. Some of mine got really huge this year! Look at this one....
Fortunately it was tightly knit, tender, and delicious!
Remember, Brussel's Sprouts taste best after the first freeze....so don't eat them all now! In fact, not many people realize that these plants are not merely hibernating right now....they are actually STILL GROWING, so any sprouts you've left outside will continue to plump up for the next few months!