- If prepared properly, little N is needed the year of growth. Apply 0.6-1 ounce N per tree at bud break and again 4 weeks later.
Leaf analysis (heavy crop will increase N by 0.2-0.3%)
- Hard cultivars - 2.2-2.4%.
- Soft cultivars - 1.8-2.2%.
- Nonbearing years - 0.5-2 feet of growth.
- Bearing years - 8-15 inches of growth.
- If the percent N in leaves is greater than optimum, decrease N application by 10% for each 0.1% leaf N is above optimum.
- If the percent N in leaves is less than optimum, increase N application by 10% for each 0.1% leaf N is below optimum.
- For possible set improvement, apply urea (spray grade with less than 0.25% biuret) at tight cluster to pink at a rate of 3 lbs/100 gal and again at petal fall to seven days after petal fall at a rate of 5 lbs/100 gal.
- Generally K is required only on bearing trees, except for newly cleared land or on particularly sandy or gravelly soil.
- Leaf analysis (heavy crop will have 0.4% lower)
- All cultivars - 1.2-1.8%.
- Deficient K - 120-180 lbs K2O/acre (200-300 lbs muriate of potash -- KCl).
- Optimum K - 60-90 lbs K2O/acre (100-150 lbs muriate of potash -- KCl).
- Excess K - discontinue for a year.
All cultivars - 0.35-0.50%.
- Deficient Mg - use dolomitic limestone plus 15 lbs Epson salts/100 gal. in petal fall, first cover, and second cover sprays (avoid high temperatures or slow drying).
- Optimum Mg - continue present program.
- All cultivars - 35-50 ppm.
- General program - 1-2 lbs B/acre/year to the soil or 1 lb solubor/100 gal in first and third cover sprays (do not apply later than 30 days after petal fall)
- Less than 25 ppm B 1.7 lbs solubor/100 gal in fall plus 1 lb solubor/100 gal prebloom or 1 lb solubor/100 gal prebloom, first, and third covers or 1 lb solubor/100 gal prebloom plus 2-3 lbs B on the soil
- 25 to 34 ppm B continue present program plus 1 lb solubor/100 gal at tight cluster or petal fall 35 to 50 ppm B continue present program
- More than 50 ppm B discontinue application for one year
- Foliar applications in the fall (postharvest before leaf drop) may improve flower development, pollination, and set. Spring applications (first and second cover) may improve recovery from cold damage.
- All cultivars - 35-135 ppm.
- Deficient Mn 4 lbs manganese sulfate/100 gal in the first cover spray, or 3 sprays of a Mn-containing fungicide.
- All cultivars - 25-50 ppm.
- Deficient Zn - 1 lb or 1 quart zinc chelate (EDTA)/100 gal at tight cluster and in the second cover spray.
- All cultivars - 7-12 ppm.
- Deficient Cu - Bordeaux mix or copper sulfate (2 lbs/100 gal) at green tip to 1/4-inch green.