There are a number of studies showing Alternate Bearing (AB) as a naturally occurring and internally regulated process. That’s equivalent to saying that your family has a history of high blood pressure, when it’s actually a family history of poor living and eating habits that has caused the problem.
After harvest, a perennial crop is completely depleted. All the energy that the plant/tree can muster has gone into fruit/nut ripening. Failure to adequately nourish your plant/tree with significant post-harvest applications means entering the dormant period with little energy in storage for a spring push. There are many studies stating that a perennial crop takes in from 30% to 50% of its total nutrient uptake for the season at post-harvest. That’s a window that everyone should take advantage of!
Here’s the scenario for AB. The grower has little or no post-harvest applications and the plant/tree goes into dormancy depleted. In the spring, the grower’s fertility applications are a futile attempt to play catch-up on an already exhausted plant whose metabolism is now in full swing. Then the plant/tree pushes fruit ripening at the end of the season and is completely depleted again. The lack of a post-harvest application fails to recharge the batteries or build carbohydrate reserves stored in the woody tissues of the plant, and the same process starts all over again. Only this time, the perennial is more depleted than the previous year and the outcome is an AB yield.
Bob Wilt at Sunset Valley Organics concurs: “After harvest the plant is very low on energy and needs to prepare for winter, stockpiling carbohydrates (sugar) to get through the winter and initial spring and new growth. Also these ‘sugars’ act as anti-freeze when it gets cold and will help the plant get though freezing conditions. Many growers experience ‘alternating years’ where they have a heavy crop one year and a light crop the next. This is a perfect example of a lack of energy post-harvest. After harvest, if the plant is short of energy it will take the low road and go in to vegetative the following year. Conversely if the plant has adequate energy in the fall it will produce a heavy crop the following year. I personally experienced this situation many times, until I started understanding the energy needs of the plant. Now that I feed post-harvest I consistently have good yields with high quality (nutrient density) every year, without winter damage.”
We recommend using our fish hydrolysate, Pacific Gro (which, by the way, Bob uses) along with MetaGrow ST compost teas, Agrostim or Supergrow foliar or soil fertilizers and other carbon sources. This gets the soil biology revved up, which in turn recharges the plant for its winter nap and spring awakening.