Peach

Feed nitrogen at bloom, then split the rest

Make the first application somewhere between bloom and petal fall using a complete fertilizer such as 16-4-8, 12-6-6, 12-4-8 or 10-10-10, then a second about two months later, and a third after harvest if the tree carried a crop. Young trees in their first three years need less than a mature bearing tree. Peaches pull more out of the soil than most tree fruit and respond to nitrogen more than to any other nutrient, and bearing trees ship nitrogen and potassium out of the orchard in every fruit picked. Splitting the dose feeds the tree when it is actually growing instead of dumping it all at once.

⚠ Do not apply fertilizer after August 15. Late nitrogen pushes soft growth that will not harden off before winter, and excess nitrogen drives water sprouts and washes color out of the fruit. Soil test rather than guessing.

Thin the fruit to a hand's width apart

About four weeks after full bloom, once the shucks have split and you can see which fruit has really set, pull fruit off by hand until the ones left are spaced about 6 inches apart along each limb. Take the small, damaged and doubled fruit first. A peach sets far more fruit than it can ever mature, and left alone it will ripen a heavy crop of small bland fruit and snap its own limbs under the weight. Thinning is what turns the same amount of sugar into fewer, larger, better-tasting peaches.

Prune to an open center at the tail end of dormancy

Prune in the last stretch of dormancy, as the coldest weather breaks and the buds begin to swell but before they open - in the warm end of the range this is mid-February to early March, further north it is later, so watch the buds rather than the calendar. Keep three or four scaffold limbs with wide crotch angles above 45 degrees, the lowest about 15 inches off the ground and the highest about 30 inches, and cut out the center so the tree holds a vase shape that light can reach the bottom of. Do not prune between leaf drop and midwinter. Peaches fruit only on wood that grew the previous season, so a tree left unpruned walks its crop higher and further out every year until the fruiting wood is all out of reach. Holding the cuts until the end of dormancy also keeps open wounds from sitting through the cold, which is when winter injury and bacterial canker get in, and it lets you see which wood the winter already killed before you decide what to keep.

⚠ Heavy pruning drastically reduces the crop, so cut moderately rather than trying to fix an overgrown tree in a single season. Pruning by the calendar in a cold zone means cutting in midwinter - wait for bud swell.

Strip the mummies after harvest

Once the crop is off, go through the tree and pull down every shriveled mummified fruit still hanging, and rake up the ones on the ground. Get them out of the orchard rather than composting them at the base of the tree. Leave the twigs with sunken cankers for the dormant pruning pass at the end of winter - cut those out then, when the wounds will not be sitting open through the growing season, and burn or bin the prunings. Brown rot overwinters in exactly two places: mummified fruit on the tree and on the ground, and the cankers on twigs and branches. Those mummies are what produce next spring's spores during bloom, so pulling them now removes the inoculum before it can start the cycle over, and the cankers come out with the rest of the dormant cuts.

Peach dormant fungicideFeb – Nov

Apply a copper or chlorothalonil spray at leaf drop and again at bud swell. Times the two windows that stop peach leaf curl.

⚠ Read the label; leaf curl can't be cured once leaves emerge.

Brown rot: fungicide while the flowers are open

As the flowers open, spray captan or chlorothalonil to protect the blossoms from brown rot. Repeat if bloom stretches out over a long cool wet spell, since flowers that open later are unprotected by the earlier spray. Monilinia fructicola infects through the stigmas and anthers of open flowers, and a blighted blossom becomes the twig canker that seeds the fruit rot months later. Fungicides only prevent new infection, they cannot cure what has already gone in.

⚠ Fungicide only at this stage. Never add or apply an insecticide during bloom, because honey bees, native bees and other beneficial insects working the flowers will be killed.

Plum curculio and oriental fruit moth: first insecticide at petal fall

Once the petals have dropped and the bees have left the tree, spray malathion for plum curculio, catfacing insects and oriental fruit moth, and repeat through shuck split into first cover. Plum curculio females cut crescent-shaped egg scars into the young fruit as soon as it sizes, and the overwintering generation of oriental fruit moth is bored into shoots at this same moment. Hitting this window is what stops both from establishing a population that runs all season.

⚠ Do not spray until the petals are off - insecticide during bloom kills honey bees and native bees. Malathion carries a 7-day pre-harvest interval on peach.

Peachtree borer: soak the lower trunk during moth flight

Hang a pheromone trap and spray permethrin or carbaryl on the lower trunk and the ground at the base of the tree once males start showing up, then again two to three weeks later if they are still flying. Wet the bark from the lower scaffolds down to the soil line until it puddles at the base. This is a trunk spray, not a canopy or fruit spray. Females lay on the lower trunk bark and in soil cracks near the base, the eggs hatch in about ten days, and the larvae tunnel straight into the sapwood below the soil line where nothing can reach them. The insecticide only works as a barrier on the bark during the ten days between laying and hatching, so it has to be there while moths are flying.

⚠ Time this by trapped moths, not by the calendar - flight runs anywhere from mid-June into September depending on where you are, and a single application will not hold long enough on its own. Look for oozing clear gum mixed with sawdust-like frass at the soil line as your confirmation the pest is present.

Brown rot: cover the fruit as it ripens

Start covering the fruit again in the last few weeks before picking, on a 10 to 14 day interval, and shorten the interval during frequent rain. Both propiconazole and captan carry a 0-day pre-harvest interval on peach, so either can legally be used right up to picking - read your own product's label, since the interval belongs to the label and not to the active ingredient in the abstract. Ripening fruit turns sharply susceptible to brown rot as its sugar climbs, and a gap in coverage now lets in latent infections that stay invisible until the fruit rots in the bowl days after you pick it. Sugar-rich fruit and warm wet weather are exactly what the fungus needs to sporulate.

⚠ On peach, propiconazole carries a 0-day pre-harvest interval with a 12-hour re-entry interval, and captan a 0-day pre-harvest interval with a 24-hour re-entry interval - do not enter the block inside the re-entry interval. A 0-day interval is not a licence to ignore the label: follow the label's limit on total seasonal applications and its resistance-management rotation, and wash fruit before eating.