Four of the critical stages of high nutrient demand for fruit trees are pollination, early development, mid to late season, and late season/postharvest. During these times, growers should be sure to maintain healthy fertilization levels.
Some tips for nutrient management during each stage of fruit production:
Stage 1: Pollination
Fertilizing for fruit set actually starts the season before during bud development. This year, you’ll feed the buds from the prior season for good fruit set for this season. Fertilization during bud development is important because you can always thin fruit off, but you can’t create blossoms and fruit set if you don’t have it at the beginning. Boron is critical during pollination and early fruit set. Many growers apply a foliar boron spray, particularly during early bloom. Foliar applications are the most efficient method of uptake, and a foliar spray applies nutrient right where it needs to be – on the buds themselves. The buds are a small target, so growers don’t need to apply much. In most cases, only a pound or two of boron per acre per season would be needed.
Fase2 growth nutrients during this phase will stimulate growth in perennial crops such as orchards and vineyards. Fase2 promotes fruit set and bud retention and is intended for foliar applications.
Stage 2: Early Development
Early development is largely about nitrogen and phosphorus, applied to produce a good canopy and for the energy to get and hold fruit set. Overall, fertilizer rates will be based on what’s appropriate for the age of the tree and the results of a soil test.
Stage 3: Mid To Late Season
Calcium and potassium are the nutrients to monitor mid- to late-season. While every variety will need more potassium during this time, calcium is especially important for Honeycrisp apples.
Foliar applications are the way to fine tune a crop, fill in certain growth stages, or deal with a dry period of little water uptake – but start with the soil to get the right balance. As trees will also be setting buds for next season during this phase, micronutrients can be important to apply at this time.
Stage 4: Late Season/Post Harvest
Some of the very early season apple varieties and all types of cherries will have a fair bit of growing to do, even into the late season. For these, maintaining insecticide and fungicide applications, even after harvest, will maintain leaves as long as possible and give trees more energy going into winter. Some growers have also been looking into late-season nitrogen as a way to improve spring flush and vigor.
Throughout the entire growing season, Pro-Germinator and Sure-K are two main nutrition products that support a balanced fertilizer program. Pro-Germinator is primarily used as a soil application, but it can also be applied as a foliar nutrient. It provides season-long phosphorus availability. Sure-K provides potassium for foliar or fertigation applications, which allows flexible use depending on crop or variety. For those varieties that need additional calcium, Liberate Ca from AgroLiquid can be tank mixed with many other products for efficient source of calcium applications.