Growing Fruit Organically + Disease-resistant varieties

Greenmantle has always been committed to the organic approach to horticulture. This applies both to the nursery stock we sell and our own personal garden and orchard. We believe that in the long run, organic methods will promote healthier plants, people, and planet.

Of course, we realize that not everyone agrees with this philosophy, and we also understand that growing "clean" fruit organically can be a very difficult and elusive goal for customers, particularly in humid regions of the country. For those who wish to pursue a program of fruit culture that eschews dependence on chemical inputs (or at least uses less than conventional methods normally require) - we offer the following suggestions:

1. Natural organic orcharding begins with the soil. Eventually, your trees' roots may mine every square inch of your orchard ground in search of nutrients. When possible, begin a soil-building program before the trees are planted. And develop a long-range plan to manage and maintain the tilth of your soil. The organic and bio-dynamic movements have developed many useful methods (legume cover-cropping, mulching, compost dressing) to achieve the goal of sustainable orcharding.

"It goes without saying that soil improvement is the
fundamental concern of orchard management."

While building up the tilth and organic content of the soil can solve a multitude of problems, certain situations may require additional "inputs". Sometimes a comprehensive soil test will indicate a specific nutrient imbalance that needs to be corrected; the N-P-K paradigm seldom tells the whole story. Fruit trees can be very sensitive to mineral deficiences. Supplements that provide major nutrients like calcium, magnesium, and sulfur as well as minor nutrients such as boron, copper, and zinc may bring about dramatic improvement in tree health and fruit quality. Compost teas, fish emulsion, and seaweed meal are all valuable sources of trace elements. These can be applied to the soil and/or sprayed as a"foliar feed". The latter approach may offer some extra benefits in increased disease-resistance and cold-hardiness.

Greenmantle's Chief Fertilizing Officer bestows his approval on some product

2. Develop a sense of place - and understand its inherent virtues and limitations. Soil, climate, and microclimate will affect every decision. Once you determine what can be expected to grow well - and what will be marginal, experimental, or impossible - you can make realistic choices. This learning process might entail trial-and-error planting, consultations with experts, as well as checking with more experienced neighbors. Our own education meant visiting numerous abandoned homestead orchards and interviewing local old-timers who knew fruit. Plus lots of mistakes and failures. Perseverance - we hope - will further.....

"An organic farm, properly speaking, is not one that uses certain methods and substances and avoids others; it is a farm whose structure is formed in imitation of the structure of a natural system; it has the integrity, the independence, and the benign dependence of an organism."

3. Start with healthy, well-formed nursery stock. Good tree structure begins at planting time. Unbranched one-year whips are obviously simple to deal with; a light heading back will encourage lateral shoot growth and stiffen the leader. Larger branched trees usually need to be pruned more heavily to compensate for any root damage and to promote a strong framework. Each branch should be spaced about 12 inches apart and oriented in its own direction, typically about 120 degrees from the adjacent branches. Damaged or poorly formed branches (eg. bad crotch angles) should be removed now. The few remaining limbs are then headed back, perhaps halfway to the trunk - making the cut at an appropriate bud. Growth can be directed by pruning to outside, inside, or left/right buds. Later in the season, the tree should be inspected and re-pruned if necessary to insure that the most useful bud is continuing the growth of the branch. Greenmantle Nursery prunes all its trees before shipment so they are ready for planting.

4. Plant carefully and provide appropriate aftercare and protection.
Planting depth and orientation toward the sun are also critical considerations. Too deep or too shallow will cause a multitude of problems later on. Newly planted trees should be given a solar orientation that minimizes damage from sunscald. Usually this means pointing the graft scar to the north so that the initial topgrowth leans toward the south. A slight tilt of the whole tree in this direction might be useful. In addition, a coating of whitewash or paint (white exterior latex) should prevent sunscald and the consequent girdling by flatheaded borers.

Chrysobothris femorata - Flatheaded Apple Borer.
It preys particularly on young, drought-stressed trees.

Establishing your trees of course means protecting them from marauding mammals (deer, rabbits, dogs, rodents, etc.) Young trees that have been defoliated by grazing animals may never really recover their health and vigor - they are certainly more prone to sunscald, borers, poor structure, and stress-related diseases. Good fences, at least in the early years after planting, are an absolute requirement in most regions.

Finally, we cannot over-emphasize the importance of adequate irrigation during those critical first years. Here in Northern California, drought stress leads to stunted, weak trees that cannot support the weight their own fruit. And for young trees, this situation is yet another invitation to borer devastation. Figure out a schedule that provides deep regular watering - at least till the tree is firmly established.

Foxwhelp apples are honestly depicted by the great British pomologist and illustrator Thomas Hogg (1818-1897) as very susceptible to apple scab. Foxwhelp of course, is regarded as the premier hard cider apple of Great Britain, so a little blemishing can't hurt. Who knows, maybe the scab even enhances the flavor of the fermented brew? At any rate, a working cider press is a godsend to the organic apple grower…..

5. Cultivate reasonable expectations. A misguided quest for superficial perfection too often becomes the justification for toxic sprays. (This is called "clean" fruit.) Modern cosmetic standards for fruit may be somewhat unrealistic . Even here in California, with low humidity and no rainfall during the growing season, scab can blemish a certain percentage of our apple crop - depending on variety. Since we don't market much fruit, this doesn't bother us. At any rate, less than perfect fruit can make fine apple sauce and cider. Of course, some kinds of fruit are easier to grow organically than others. So.......

6. Make informed choices for both variety and rootstock . Nowadays, fruit growers have many options to choose from, and these may include disease-resistant selections: scab and fireblight resistant apple varieties, fireblight resistant pears, peaches immune to leaf curl. Just make sure that you need this type of resistance. If a disease is not a real problem, then ordinary varieties may produce higher quality fruit. Also, it is useful to remember that even the disease-resistant varieties are still susceptible to insect damage.

Bartlett Pear - An old classic that still dominates the marketplace, Bartlett goes back to 1770's England, where it was originally known as "Williams Bon Chretien". It came to North America a generation later and was renamed "Bartlett". We grow a strain of this variety that has been selected for improved resistance to fireblight by researchers at the University of Illinois - Urbana.

A sandpear hybrid like Kieffer may be very appreciated by pear growers in a fireblight infested region like Mississippi - but why plant this gritty fruit in Northern California or Oregon where exquisite dessert varieties like Comice and Bosc flourish? Sometimes the decision-making process is not as clear-cut or obvious. We have long been fascinated by the quandary afforded by disease-resistant apples: Is it better to grow a good scab-resistant variety like Liberty - or a great, but scab-prone apple like Spitzenberg? As nurserymen/ collectors we grow both. But we expect that many of our customers will ponder this dilemma.

Rootstock selection can be even more critical to the health and longevity of the tree. Natural vigor may require a taller ladder, but it often means a healthier orchard. Knowing your soil type and its drainage tendencies is an important consideration. For instance, MARK apple rootstock thrives in heavier clay loams, but seems poorly adapted to sand typical of irrigated high desert plantings. Mazzard cherry tolerates winter "wet feet" better than most other cherry roots. And the Malling- Merton apple series (eg.MM111) was developed in part to resist soil infestations of wooly apple aphis.

Organic growers should also keep in mind that many modern orchard practices were developed in conjunction with a heavy spray program. So intensive (close) spacing of dwarf trees in trellised rows typically means more fungus diseases unless regularly sprayed. Likewise, many genetic dwarf varieties, especially peaches, have such a dense growth habit that disease problems are inevitable without chemical intervention.

Caused by the fungus Taphrina deformans, Peach Leaf Curl plagues Prunus persica wherever wet spring weather is common. Trees can recover from the damage and still bear a crop, but the disease obviously results in stress.

7. Don't become so focused on the fruit that you forget the tree . Healthy fruit grows on healthy trees. Too many people seem obsessed about getting a precocious crop off of their young trees. This can lead to broken or misshapen branches and stunted trees. It is often best to strip off a premature fruit set to allow the tree to develop a strong, well-formed framework that can hold a crop year after year.

Getting a young tree established during its adolescent period is crucial to long-term success. Judicious pruning and training means less remedial damage control later on. A properly structured tree will allow optimum air circulation and light penetration; this results in better quality, less blemished fruit. Too much openess, however, can lead to sunburn and borer damage. Again, we do recommend the use of white paint on young trunks when appropriate.

Balanced feeding and watering is, of course, essential. The orchardist should carefully monitor shoot growth - both length and caliper - and adjust irrigation and fertilization accordingly. This requires some experience with "normal" growth rates for trees in a particular zone. Here in California, drought stress - and concurrent lack of vigor - can frequently lead to attack from the flatheaded apple borer. On the other hand, excessive watering and fertilizing - whether chemical or organic - can make a tree more susceptible to disease. Fireflight (Erwinia) in particular likes to prey on apple and pear trees that have been "hyped" with too much nitrogen. Go a little slow with the manure teas and fish emulsion - even though they are certified organic .....

Fireblight (Erwinia amylovora) damage in top of old pear tree. This problem can often be contained by careful pruning and good cultural practice. In regions where fireblight means an ongoing struggle, growers should consider resistant varieties and rootstocks.

8. Learn about non-chemical methods of pest control appropriate to your region. Timely spraying with oil and/or lime sulfur has long been utilized to prevent damage from both insects (mites, San Jose scale, aphis, and pear scylla) and diseases (powdery mildew and various scabs). For many years, organic practitioners have been developing "non-toxic" approaches to monitoring and controlling insest pests (eg. apple maggot, codlin moth, etc.) Methods include trapping, releasing of predatory insescts, and biological sprays. Timing is all important with any pest management practice, organic or chemical.

Mr. Bean and his revolutionary new spraying equipment - circa 1885.
Lead arsenate was a favorite....Note protective gear.

Organic fruit growers wishing to market a bug-free crop will of necessity become expert in the life cycles of insect pests as well as the subtleties of temperature variation and fruit bud development.

9. The value of Good Housekeeping in the orchard should never be underestimated. Sanitation can make a big difference with many diseases as well as insect and rodent pests. Windfall fruit allows pathogens and worms to winter over safely in the orchard. Likewise, fallen leaves can harbor disease spores and promote re-infestation in the Spring. Raking and burning orchard debris - including all pruning wood - can really help. Pruning out diseased and dead wood is a vital orchard hygiene practice. Where fireblight is endemic, careful pruning with sterilized tools is an important element of control.

Finally, we should remind our customers of the need to keep mulching material pulled back from your tree trunks, particularly in winter. Rodents (mice, voles, etc.) love to nest in this organic debris; the result is gnawed bark and possible girdling of the tree.

10. Balance human needs with those of the wildlife community, while safeguarding the well-being of the orchard. Like the 'Peaceable Kingdom', natural orcharding is a beautiful ideal that offers inspiration and hope to folks struggling to grow fruit without doing harm. Fruit trees, however, are horticultural artifacts developed by humans over the millenia to serve their own anthropocentric agenda. And this sometimes means an inherent conflict with the wild animals that co-exist with us. We are obviously not the only ones who delight in fresh, tree-ripened fruit. Many fruit gardeners are willing to share the harvest with other creatures, especially when there are no other realistic options. But when the animals in question damage and destroy the trees, even mild-mannered animal-lovers have been known to take up arms.

Our own experience points to only one long-term sustainable approach to orchard protection: Good fences do make good neighbors of our fellow creatures. Building and maintaining an orchard fence that keeps out animal interlopers is a formidable challenge…….. yet there is no other dependable method - natural or unnatural - to protect the attractive nuisance we humans call the Orchard.

"A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise."

Thinking About Growing Fruit Organically