Pear

Fertilize by last year's shoot growth, not by the calendar

In spring, measure last season's terminal shoot growth before you fertilize anything. A pear that grew less than 6 inches gets about 1 pound of calcium nitrate. A pear older than 3 years that grew more than 12 inches gets no nitrogen at all - only sul-po-mag, and only if a soil or tissue test calls for potassium or magnesium. Test the soil every three years. Nitrogen on an already-vigorous pear buys succulent shoots, and succulent shoot tissue is exactly what fire blight infects and races through - so on this crop the shoot ruler decides the fertilizer, not the season.

Thin to one pear per cluster as soon as the fruitlets set

Once the fruitlets have set, thin to one fruit per cluster and space the remaining clusters about 6 inches apart along the limb. Do it as early as you can get to it. Next year's flower buds are initiated over the four to six week period following full bloom, so aim to have thinning finished before that window is out - the earlier the job is done, the more it accomplishes, and thinning at the tail end of it is largely too late to buy you a crop next year. The tree is setting next year's flower buds during those same weeks after bloom, so a heavy crop left on spends the tree's reserves on seed and shuts down next season's flowers - thinning early buys both fruit size this year and a crop next year.

Dormant pruning: train a central leader before growth startsFeb – Mar

Prune while the tree is fully dormant, before active growth begins in spring. Keep one central trunk with tiers of wide-angled scaffolds and let the canopy taper narrower at the top, so light reaches the lower limbs. Pear limbs grow narrow and upright on their own, so spread young branches with weights, ties, or spacer sticks. Avoid heavy fall pruning. Pears bear on long-lived spurs that need direct light to stay fruitful, so an open, tapered canopy is what keeps spurs producing throughout the tree instead of only in the top tier.

⚠ After a severe winter pruning, do not fertilize the tree that spring; a heavily pruned tree may need no fertilizer for one to two years, and pushing succulent growth on a pear invites fire blight.

Cut out fire blight cankers while the tree is dormantJan – Feb

Before growth starts, go over the tree and find last season's fire blight: sunken dark cankers on limbs and blackened shoots hooked over like a shepherd's crook. Cut each one a minimum of 8 to 12 inches below any sign of infected tissue. Take out the suckers at the base of the tree at the same time, and destroy everything you remove rather than leaving it in the row. The fire blight bacterium overwinters alive at the margins of those cankers, and in spring they ooze the inoculum that infects the opening blossoms; cutting them out in dormancy removes the season's first source of the disease from the tree.

⚠ Disinfect pruning tools between cuts with a bleach solution or alcohol, because the bacterium moves from cut to cut on the blades. Base suckers are highly vulnerable to infection that can run straight into the trunk.

Dormant horticultural oil for pear psylla, before the buds swell

Watch the buds, not the calendar - the date this comes due moves by weeks between regions. Any time from full dormancy until the buds swell, cover the whole tree with horticultural oil, and include oil again in the delayed dormant spray as the buds break. Green tip is the outside limit: the oil has to be on the tree before the overwintering females mature their eggs, and egg laying runs from then through white bud. Pear psylla adults overwinter on the tree and become active any time the temperature is above 40 F, laying eggs from late winter through white bud. Oil works less as a poison than as exclusion, and an early oil has been shown to delay egg laying by over 95 percent for about five weeks.

⚠ Timing is the whole rule: applied after egg laying has started, the oil has missed its window. Follow the label for temperature limits - oil applied in freezing or hot conditions can injure the tree.

Fire blight: delayed-dormant copper between bud swell and green tip

Between bud swell (silver tip) and green tip, when leaves are just starting to emerge, apply a fixed copper spray. Put it on as a high-volume application that thoroughly wets every exposed surface - twigs, spurs, and old canker faces. Copper knocks down the bacterial populations that overwintered on the bark and in canker margins before rain can wash them into the opening blossoms, which is where fire blight actually enters the tree.

⚠ This is a delayed-dormant timing only, between silver tip and green tip. Once leaves are out, the copper window has closed.

Fire blight: streptomycin on open blossoms during warm, wet bloom

When wet weather lands during bloom and temperatures run about 60 to 75 F, spray streptomycin as soon as the flowers open and repeat at 3 to 4 day intervals as long as blossoms are present. A minimum of two applications is needed for control. The open flower is where Erwinia amylovora multiplies; in warm weather the population on a single blossom can explode within a day or two, and rain then carries the bacteria down into the nectary where they infect.

⚠ Keep a minimum 50-day interval between the last streptomycin application and harvest. Streptomycin is an antibiotic, not an insecticide - never substitute an insecticide at this timing, because bees are working the open flowers.

Codling moth: first spray after the petals are off

Wait until petal fall, then begin codling moth sprays about three weeks after full bloom, when the first eggs are hatching. Spinosad and codling moth granulovirus are both effective; repeat at the interval on the label, generally every 7 to 10 days while moths are flying. Rake up and destroy dropped fruit as it falls to break the cycle. Newly hatched codling moth larvae bore into the fruit almost immediately, and once inside the fruit no spray can reach them - the only opening is the short span between egg hatch and entry.

⚠ Apply after petal fall and never during bloom, when the risk of harming pollinators is high. Spinosad needs repeated applications within each generation to give acceptable control.

Pick pears hard and green, then chill them before ripening

Pick European pears when they are full sized for the variety but still green and firm, not soft on the tree. Then give them their cold period: Bartlett needs only 1 to 2 days of refrigeration, while Bosc, Comice, and D'Anjou need 2 to 6 weeks. After chilling, ripen at 65 to 75 F in high humidity - roughly 5 days for Bartlett, 7 for Bosc and Comice, 9 for D'Anjou. They are ready when the flesh just below the stem yields slightly to gentle pressure. European pears resist ripening straight off the tree, and without that postharvest chilling a mature fruit will simply shrivel and decompose instead of ripening. Store-bought pears have already had their cold period, which is why home-grown fruit seems to fail.