Hops grow vertically as one or more vines that spiral up a twine or anything else convenient. Depending on latitude, location, and variety, they sprout from about mid-March or April and grow through the summer and early fall. A single plant can easily grow 40 feet tall when it is mature but growth in the first year is usually much less. In most instances by the second or third year the plants will exhibit full growth. Height is very closely linked to the amount of sunshine the plant gets.
Hops grow best in full sun and you should pick a spot with the best possible southern exposure. Hops grow best in loose, well drained soil. Blended peat moss and sand make a good hops growing environment. In cases of poor soil drainage, it can be helpful to create a mound of soil a foot or so tall which will aid drainage.
Hops need lots of water. As they grow be sure to give them a very good soaking at least once a week. Mulch in the summer helps with weed control and also holds additional water. Also, hops have big appetites. Composted cow manure has been reported to be an excellent well balanced fertilizer.
Once a bed has been prepared the rhizomes are planted about four inches below the soil surface with any obvious buds coming from the rhizome oriented to point upward toward the soil surface.
After several inches or so the new vines should be thinned such that just the most healthy and vigorous three vines are left to continue growing. This will be an ongoing process as new shoots may show up later but the initial thinning is an important one. It's been reported that the young shoots that are culled may be steamed and eaten like asparagus. On the other hand, some growers espouse cutting the new shoots at all, allowing all vines to grow to full height.
As the vines grow over a foot tall they should be trained to grow up a twine. This can be done by twisting the vine around the line. You may have to repeat this for a few days before the vine gets the idea. Remember, like most plants, hops will "follow" the sun, and so have a natural tendency to wrap from east to west, or counter-clockwise looking up for a south facing plant.
The most common hops trellis consists of strings running from the roof of a building down to stakes driven into the soil near the plants. Another option, often used by commercial growers, consists of a large central pole, with strings running from the top of the pole down to the foot of each plant, similar to the spokes on a wheel. Expect the string or twine to hold a lot of weight as the vines grow tall. A 25+ foot plant may weigh 20+ pounds.
Hop blossoms start out looking like large sand burrs and then take on a characteristic cone shape and grow in size. The size of a fully developed cone depends on the variety, varying from one to two inches long by one half to one inch in diameter.
The hops are fully mature and ready for picking when two changes take place. First, immature hops have a damp, soft feel and when squeezed slightly tend to stay compressed. Mature hops feel more like paper, spring back when squeezed and feel noticeably lighter. The second key test is to pick an average example hop and cut it lengthwise down the center with a knife. When ready to pick the yellow powder (the lupulin sacs containing the essential oils and bitter substances that are "where it's at") will be a dark shade of yellow, like the stripes on a highway, and it will be pungent. If a light shade of yellow then chances are the hops are immature.
When ready to pick it is best to snip the stems of the cones with scissors or a knife to avoid jarring the hops and knocking lupulin powder out or worse, pulling the center of the cone out with the stem, causing a great loss of lupulin. Touching hops plants can cause skin irritation in some people; gloves and long sleeves can help in this matter.
Just picked hops are roughly 80 percent water; if left alone they spoil rapidly. For proper storage most of the water is removed by drying. A good drying method it to lie the hops on a card or screen in an attic. Just a few hours during the heat of summer or a few hours more in cooler weather is enough to dry the hops. Use a before and after weighing and trial and error to try to achieve about 7-10 percent residual moisture after drying.
After drying, hops keep best at low temperatures and away from oxygen. A kitchen freezer easily takes care of temperature but to get the hops away from oxygen is difficult. Tightly packing hops in canning jars will minimize the trapped air but be careful not to use too much force and break the all important lupulin sacs since this accelerates oxidation. Purging the canning jar of oxygen by blowing in carbon dioxide from a kegging system will also help prolong freshness.
It's common to get 4 or 5 harvests per year by picking the biggest, most mature hops every two weeks or so as the flowers ripen. Patience and judgement are important since cones left on the vine too long turn brown and are obviously oxidized and spoiled, while immature hops have little lupulin in them.
At the end of the growing season when the leaves have fallen or turned brown, cut the vines at the surface of the soil and if possible remove the twine. After cutting back the vines a layer of three or four inches of mulch and composted manure can be put over the exposed vines for insulation and nutrition during the winter.
Japanese beetles are the number one nuisance in many areas. A common remedy is to position a "Bag a Bug" type beetle trap about 30 feet directly up wind from the hop vines. There is some concern that the "Bag a Bug" traps may actually attract more beetles than they catch, but that probably depends on the situation. Certain plants such as rose bushes may also attract the beetles, so it's best to keep those plants away from your hops. Also, the beetles' larvae live in the ground, and in cases of extreme Japanese Beetle infestation the surrounding lawn may need to be treated accordingly. A number of other pests, such as aphids, can harm hops, and can be treated with any number of pesticides. Remember, though, that you will be consuming these hops, and should use low toxicity natural pesticides, such as 1% Rotenone dust, for direct pest control on the plants. As with any consumable, you should ensure that any pesticide is well washed off before using the hops.
One other hazard is animals. A short fence of rabbit wire will keep cats, dogs, rabbits, etc. at bay. Deer have also been reported to be fond of hops.
Rhizomes are available from an increasing number of sources. American Brewmaster in Raleigh, NC and Freshops in Philomath, OR are two well-known suppliers. Cost is usually a few dollars each. They should be kept in plastic bags, moist and cold in your refrigerator until they are planted.
Additional information about hop growing can be found in "Homegrown Hops" by David R. Beach. Also, the 1990 special issue of "Zymurgy" is devoted to hops and contains an article about growing hops by Pierre Rajotte. The AHA also has additional hops-oriented publications.