Grow Better Blueberries with Haifa products

Nutrition of blueberries: general rules

 

♦ When setting the application rates, consider expected yield and required balance of nutrients
♦ Provide complete fertilization, with macro- and micro-nutrients
♦ Consider cation ratios Ca/K, Ca/Mg, Ca/(K+Mg)
♦ Consider NH4/NO3 ratio. The majority of nitrogen should be supplied as nitrate
♦ Use soluble and chloride-free potassium
♦ Use diagnostic tools such as soil analysis, foliar, suction probes, chlorophyll meters, etc.
♦ Split applications according to the plant’s uptake dynamics

 

Berries hate salinity:

Berry type	EC (dS / m) at which the yield decreased by:
	10%	25%	50%
Blackberry	1.5	2.0	2.5
Blueberry	1.0	1.5	2.0
Raspberry	1.5	2.0	2.5

Considerable yield reduction occurs at relatively low EC levels.

 

Nitrogen Deficiency:

• Nitrogen leaching, resulting from intensive rains or excessive irrigation, is a common cause of deficiencies
• Typical symptoms: small pale leaves, sometimes with tiny red spots
• Blueberries are salt-sensitive, so excessive N fertilization may cause mortality of young plants
• Ammonium is the preferred form of nitrogen for blueberries
• Ammonium nitrate can be used in fertilizer mixes: 

       ​- Where the nitrate portion of the mix constitutes a minor part of the total nitrogen in the mix and the soil pH is below 5.3.
       - For very light (20 pounds per acre or less) applications of nitrogen where a small amount of nitrogen is needed.

• Urea and controlled release fertilizers are also suitable sources of nitrogen for blueberries
• In the soil, urea is a rapidly converted to ammonium, which is readily absorbed by the plant
• In soils where the pH is on the high end of the range for blueberries (above 5.0), use a more acid-forming fertilizer such as ammonium sulfate

 

Timing of nitrogen applications for blueberries in Alabama ​

Phosphorus in Blueberries:

 

• Phosphorus is very important for the root establishment and for energy transfer in the plant
• Many blueberry fields are low in P:

         ​ - In acidic soils P availability is low

          - In sandy soils P is prone to leaching
 

• Pre-plant application of P is advisable
• High levels of phosphorus in the soil can tie up iron, making it unavailable to the blueberry plant
   

Recommended application rates

Application rate		Soil test P (0-45 cm / 0-12”)
Lb/acre	Kg/ha	NaHCO3	Bray I	NaOAc
100	112	0-4	0-10	0-1
80	90	4-8	10-20	1-2
60	67	9-11	20-30	2-3
30	34	12-14	30-40	3-4
10	11	15-17	40-50	4-5
0		18-25	50-100	5-10
0		Over 25	Over 100	Over 10

 

Potassium in blueberry:

• Potassium is essential for photosynthesis and water regulation. 
• On bearing plants, the annual potassium requirements can be supplied by 1-2 applications

 

Potassium recommended rates:

Application rate		Soil test K (0-45 cm / 0-12”)* * Soil extract in sodium acetate
Lb/acre	Kg/ha
80	90	0-50 ppm
50	56	50-75 ppm
30	34	75-100 ppm
0	0	Over 100

• For established plants, determine K application rates according to soil analysis

• In general:

           - To correct shortage apply 113-224 kg/ha (100-200 lbs/acre) K₂O

           - To maintain adequate level apply 56-113 kg/ha (50-100 lbs/acre) K₂O

 

 

Secondary elements:

• Blueberries have low calcium requirement
• Excessive calcium may cause iron deficiency
• Liming

           - Only when soil pH is below 3.6

           - Lime application rate: 560 kg/ha (500 lbs/acre)

           - Do not exceed this rate 

 

 

On highbush blueberries, classic magnesium deficiency is a green "Christmas Tree"
in the center of a chlorotic leaf. 

It usually occurs on the older leaves

 

 

 

On young rabbit-eye plants

magnesium deficiency is commonly shown as

pink edges and interveinal yellowing of leaves
 

 

 

Ca-Mg balance:

• Calcium - magnesium levels should be kept in balance
• The normal range is 1:8 to 1:10 (Mg:Ca)
• High calcium levels can induce magnesium deficiency
• To correct magnesium deficiency, apply 16.8 kg/ha (15 Lbs/acre) magnesium

 

Calcium and fruit quality

• Pre-harvest calcium sprays. 

           - Increase firmness of the berries

           - Extend shelf-life

           - Reduce Botrytis rot

Blueberry showing Ca deficiency (left); inside view, note corky area (right).

 

Iron in blueberry:

♦ Iron deficiencies is likely to occur when soil pH is too high

♦ The best treatment is lowering soil pH

♦ Foliar sprays of Iron chelate may alleviate some leaf symptoms but usually do not improve overall plant vigor 
 

 

 

 

Nutrigation™  program for blueberries:

Recommended fertilizers (kg/ha)			Nutrients required (kg/ha)			Timing
Multi-K	MAP	A-S	K2O	P2O5	N
60	12	32	30	7	15	Leaf emergence
90	16	42	40	10	20	Flowering
110	21	53	50	13	25	Fruit set
110	20	53	50	12	25	Fruit growth
60	13	30	30	8	15	Fruit maturation
430	82	210	200	50	100	Total

 

Texas fertigation schedule for blueberries:

Grams/plant/week			Plant diameter (feet)
K	P	N
0.5	0.5	1	1
0.75	0.75	1.5	2
1	1	2	3
1.2	1.2	2.5	4 and up

 

 

Nitrogen fertigation for blueberries:

1.Reduce annual N rate by 1/3, compared to soil application

2.Start application 2-3 weeks after bud break, continue into July

 

 

Leaf analysis

Suggested critical levels of nutrients in highbush and rabbiteye blueberry leaves

Excess	Normal: rabbiteye	Normal: highbush	Deficiency	Nutrient
2.5%	1.2-1.7%	1.8-2.1%	1.7%	N
0.8%	0.08-0.17%	0.12-0.4%	0.1%	P
0.95%	0.28-0.6%	0.35-0.65%	0.3%	K
1%	0.24-0.7%	0.4-0.4%	0.13%	Ca
0.45%	0.14-0.2%	0.12-0.25%	0.08%	Mg
NA	NA	0.12-0.2%	0.1%	S

 

Excess	Normal: rabbiteye	Normal: highbush	Deficiency	Nutrient
450 ppm	25-100 ppm	50-350 ppm	23 ppm	Mn
400 ppm	25-70 ppm	60-200 ppm	60 ppm	Fe
80 ppm	10-25 ppm	8-30 ppm	8 ppm	Zn
100 ppm	2-10 ppm	5-20 ppm	5 ppm	Cu
200 ppm	12-35 ppm	30-70 ppm	20 ppm	B

 

Need more information about growing blueberries? You can always return to the blueberry fertilizer .