With the fruit harvest winding down, don't neglect some essential chores that are necessary in the organic orchard. My peach trees are already dropping leaves creating a beautiful golden carpet on the orchard floor.
While leaves are busy showing their color, underground there is some significant root growth occurring. The tree is sending nutrients to the roots so watering is still critical until the ground freezes.
Do Not Fertilize
Once the leaves drop nutrient uptake stops. Fertilizing is not necessary in the fall.
Clean up the OrchardRemove any fallen fruit or fruit remaining on the tree. Fruit left on the tree will mummify and if infected with any disease will act as an inoculate the next spring. It's a good idea to check the trees after leaf fall to make sure there is no fruit remaining on the tree.
Mow WeedsMow down any weeds or grass. Clean weeds out of the tree wells.
In the fall, repair, fix, and enlarge your tree wells. The well should reach the drip line of the tree. Fall is a great time to add a light layer of compost. Mostly compost is added to avoid leaving a bare soil through the winter. Most of the compost applied in the spring has been worked into the soil. We add grass clipping this time of year. Be sure that you only use clippings from an organically managed lawn free of herbicides and pesticides. The compost applied on top of fallen leaves will aid in their decomposition.
Remove Leaves if Scab has been a problem
Apple scab is more of a problem in areas with cool, moist summers which is not the case in my area. However, if you do have problems with scab you must clean up the leaf litter because the spores overwinter on the leaves. Spring applications of sulfur and a fall application of copper after leaf fall will help.
Apply final spray of the season
When 50-60% of the leaves have fallen, apply the last spray of the season. This spray helps to decompose and break down the fallen leaves. I leave all leaf litter in the orchard. A spray of fish emulsion and neem oil should be targeted at the trunk, branches, and the ground. According to Micheal Philips, author of The Holistic Orchard, this helps with leaf decomposition, defend against bacterial and fungal disease in bark crevices, and the nitrogen in the fish emulsion helps with spring bud growth. In the fall, tree roots are in full stride seeking out nutrients to store in the cambium tissue. The fish fertilizer will help with this and ensure healthy spring growth. This is an important spray do not skip this step in managing your orchard.
Apply a spray of Copper after leaf fall.
Copper is effective in preventing many fungal and bacterial diseases. I go into more detail about copper and what is controls and how to apply it.
Remove any limb spreadersLimb spreaders are used on younger trees to develop good scaffold branches. In the fall the limb tissues have hardened off and the spreaders are no longer necessary. Leaving them on the trees through winter will allow snow and ice to accumulate on them and possible break branches.
Install tree guards on younger trees.Young bark is a tempting treat for voles, mice, and rabbits. Their gnawing can girdle you trees. Tree guards protect the bark from damage. I use a spiral plastic guard. I put them on young trees before the first snowfall and remove them in the spring.
Whitewash tree trunks
White washing tree trunks prevents sun scald injury on the trunks. Sun scald injury occurs when there are fluctuations in temperatures. The bark exposed to south and southwest sun become active with warm afternoon temperatures. They lose some of the cold hardiness because of this and are injured when temperatures drop to below freezing. To make the white wash, mix latex interior paint with water 1:1. Paint the entire trunk and lower scaffold of the branches. Do not use exterior paint. Some have antimicrobial products added that can damage the tree.
Disease Prevention and Copper
When leaves fall from your tree it leaves a small scar. Fungal spores and bacteria can enter these scars causing disease. Theses diseases can effect buds, leaves, fruit, and in some cases the entire tree.
Copper is a broad spectrum fungicide which controls bacterial canker, Coryneum blight or shot hole, anthracnose, bacterial leaf spot, black rots, blights, downey mildews and Septoria leaf spot.
It has been used since the 1700's and is an approved organic spray. It inactives important enzymes in fungi and bacteria.
Copper does not concentrate in the plant tissue but does persist in the soil. It should be sprayed as in dormant season after leaf fall in the fall and before bud break in the spring if necessary. Over-apllication should be avoided. Only spray if fungal disease is an issue in your orchard.
Wear appropriate clothing including long sleeves, pants, hat, and gloves. Protect your eyes and skin because it can irritate them. Follow directions on the product you purchase as well as safety recommendations.
You can purchase fixed copper as a spray or dust. Copper is protectant so cover the entire tree surface. You are creating a barrier to prevent invasion by spores and disease organisms. As I mentioned before it best used after leaf fall because you are trying to protect leaf scars from becoming an entry point for disease.