Here's an excerpt from a hop growing presentation made by Jason Perrault to some growers in Vermont:
When we are talking about hop growing, if you don't understand the developmental process that the plant
goes through, you won't be successful in growing the plant. Anyone can grow a hop plant, but if you
really want to maximize yield and quality you have to understand every developmental stage of the plant.
Each stage does have its unique characteristics. Therefore, you have to change your management scheme
to match up with those characteristics. So those main stages of growth are dormancy, spring regrowth,
vegetative growth, reproductive growth, formation of cones, and preparation for dormancy. So, in
dormancy, here late summer and fall, the plant has allocated all of its photosynthetically derived energy
down to the roots, that starch is converted into soluble sugars, and that is what it really uses to explode
into growth the next year. At this time lets go out into the field. We may not be doing much out in the
field. Maybe putting on some compost, kind of working that into the ground. We may be preparing new
yards if we are going to be planting anything. So there isn't a whole lot. The yards are pretty quiet at this
time. At the end of dormancy, the days start getting longer, they are getting warmer. The plant then starts
using those sugars and it just takes off. In this initial regrowth, for anyone who is growing hops, it just
takes off in a really rapid fashion with really long internodes, really gamey growth. These are not what
we want for crop production. The plant is really just pushing that first flush of growth out, using a ton of
energy. What we do as commercial growers is we go and cut all of that stuff off. We start with the next
flush of growth, which is a little more controlled growth. Once we get through this period, probably the
end of May or beginning of June, the plants have used up most of those soluble sugars, and now it is
using what is in the soil. So here, if it is needed, this is where you would be applying nutrients. In the
field, as I mentioned we are pruning and we do this about three weeks to a month before we are planning
on training. You time this pruning around your desired training date. So we go through and mow the
tops off. We'll do it mechanically with what we call a pruner, which is just some blades that go across the
top, taking out those aerial buds. It does two things, one, it gets the desired pruning effect that we want,
where we are getting rid of those first vines, but also were getting rid of those aerial buds. Those are the
buds that contain the overwintered powdery mildew spores, the overwintered downy mildew spores, and
some other key issues. So, we are getting rid of those. About a month later we are able to train.
It's a good explanation of why COMMERCIAL hop growers knock off the first growth. As home growers with only maybe 10 or 20 plants, we can deal with things on a little more one-to-one basis. Here's the link to the whole article:
http://www.uvm.edu/extension/cropsoil/wp-content/uploads/jason-perrault-transcript.pdf