Hops

Feed established plants in at least three split applications, aiming for the equivalent of 120 to 150 pounds of actual nitrogen per acre across the season (about 0.33 pounds of actual N per 100 square feet). MSU runs the splits from April to the beginning of July in Michigan, which in practice means from shoot emergence to about the time burrs form — use the burr stage, not the calendar, to know when to stop. Give first-year plants only one-half to two-thirds of that. Hops want little phosphorus; target potassium around 100 ppm. A bine puts on 20 feet in a single season and cannot do it on one spring dose. Nitrogen arriving late pushes soft leafy growth instead of cones and thickens the canopy that mildew wants, which is why MSU's window closes in early summer rather than running to harvest.

On plants two years and older, let the first shoots come up and cut them off at the crown once that secondary growth reaches about two feet. Never do this to a first-year plant. If a cold spring has pushed you past the point where there is still time for a full regrowth cycle before your training date, skip pruning entirely that year rather than pruning late and losing the crop. The downy mildew pathogen overwinters in the crown and buds, and the first flush of shoots carries that inoculum up into the plant as infected basal spikes. Removing that flush throws the spores away and forces a clean, uniform second flush. In a Washington commercial trial reported by MSU Extension, a four-week pruning delay dropped powdery mildew on leaves from 46 percent to 10 percent and on cones from 9 percent to 1 percent.

Once the regrowth is long enough to handle, pick the strongest bines and wrap them clockwise around the support string, then rub off the surplus shoots at the base. MSU guidance ranges from two or three bines per plant up to three or four per string, so err toward the lower end on young or weak crowns. Hops twine clockwise on their own; a bine wrapped the wrong way will unwind itself and fall. Check back every few days and re-wrap any that have slipped. Err toward training earlier rather than later. Hops set cones on the laterals of bines that reach the top wire, so the plant needs its whole season on the string. Training too late costs real yield: a Czech study cited by MSU found bines trained too late gave nearly 40 percent less. Limiting the bine count puts the crown's energy into cone-bearing growth instead of a thicket.

If downy mildew showed up last year, begin a copper fungicide as soon as basal foliage emerges in spring and repeat on a seven to ten day schedule, stretching to 14 days in hot dry spells. Actinovate AG, Regalia and Sonata are also labeled for hop and are the other options open to organic growers. Pseudoperonospora humuli overwinters in the crown and sporulates from the first infected shoots, so the spores are already flying before you can see a lesion. Copper is a protectant film on the leaf surface; it has to be there before the spore lands.

Through the fastest growth and into cone set, give a mature plant at least six gallons a day — that is MSU's floor for the peak weeks, not a ceiling, so water more in heat or sandy ground. Water at the base and keep it off the foliage where you can. First-year plants have almost no root system yet and need consistently moist, never waterlogged, soil to build one. This is the stretch when the bine is building its whole frame and then filling cones, and the crop is set by what the plant can draw in those weeks. Overhead water also wets foliage, and downy mildew spores develop in wet or foggy conditions at 60 to 70 degrees.

Starting as soon as there is foliage to take and continuing as the bines climb, strip the leaves, side suckers and stray ground shoots from the bottom four feet of every bine, and pull the weeds out of that zone too. Carry the stripped material out of the yard and destroy it rather than dropping it at the base of the plant. Downy mildew spores splash up from the soil and infect the lowest leaves first, and they develop in wet or foggy weather at 60 to 70 degrees. Opening the bottom of the canopy improves air circulation, dries those leaves faster and cuts off the ladder the disease climbs.

Scout season-long, from the time bines are climbing until harvest, sampling two leaves from about 20 plants across the yard at several heights and examining the underside with a hand lens. More than two adult mites per leaf in June is the point to act on; by mid-July the threshold rises to five to 10 mites per leaf. Twospotted spider mite development accelerates with heat right up to an upper threshold around 100 degrees, so a population invisible in June becomes a bronzed, cone-ruining infestation in weeks; cold wet weather holds it back. Mites that reach the cones are effectively unmanageable, which is why the scouting has to start before damage is visible.

Start checking cones as they lose their soft green feel. Ripe cones are papery, springy and dry to the touch, and a cone crushed in your hand stays compressed rather than springing back, leaves a sticky residue and smells strongly. Tear one open: the lupulin should be dark golden yellow. Soft cones are early; orange lupulin and a rancid, cheesy smell mean you are late. The whole planting comes ripe inside a window of about seven to ten days, and the alpha acids and aromatic oils that make the cone worth growing peak and then degrade fast. There is no second pass.

After picking, cut the bines down and take the vegetation out of the planting. Burn it, or compost it well away from the soil near the crowns rather than at their base. Any unharvested bines still standing, including on first-year plants, should come down and be destroyed after a hard frost. Downy mildew overwinters in the crown and on plant debris, and a pile of old bines at the base of the plant is next spring's inoculum sitting exactly where the new shoots will emerge through it.