Tech Gro Mira-Cal sp fertilzer calcium

Tech-Gro™ products are soluble, dry nutrients designed to be mixed and used as nutritional sprays for crops.  They have been developed with improved dispersion and wetting characteristics which makes them incredibly easy to use.

Tech-Gro B-17 and Mira-Cal™ continue to be some of our grower’s favorite products year after year.  Currently, Tech-Gro B-17 is approved as a certified organic input material in Washington and California.


  • Rapid uptake of nutrients when applied to foliage
  • Compatible with many pesticides and fungicides already used by growers
  • Nutrients applied to foliage are less likely to leach into underground water supplies

The Importance of Calcium

The role of Calcium in plant nutrition continues to grow steadily in importance.  A large number of Calcium-related disorders in fruits and vegetables are well recognized.  These include blossom-end rot in tomatoes and cucurbits, bitter-pit in apples, corking in pears and apples, internal browning and hollow-heart in potatoes, tip-burn and spotting in lettuce, blackheart of celery, cavity spots on carrots, pops or blanks in peanuts.  Properly supplied, Calcium prevents or controls these disorders.  Calcium has also been reported to reduce rain-cracking in cherries, to enhance color development in apples, peaches, and strawberries, cherries, and papayas.

Sizing Sprays with Tech-Gro Mira-Cal™


Cherries, Grapes and Oranges with       Gibberellic Acid and TG Mira-Cal

GOAL: INCREASE Calcium levels during a period of cell growth and divisions with sizing spray applications of gibberellic acid and to increase fruit quality


5 – 7 lbs./acre                Tech Gro Mira-Cal (30%Ca)

Plus label amounts of Gibberellic Acid

Mixing order: add Tech Gro Mira-Cal to the water tank first, then follow with label amounts of Gibberellic Acid

Always read and follow all label directions before spraying.

Nutrient Technologies B-17 BORIC ACID SPRAY™ is a fine, dry, free-flowing granule containing 17% elemental B derived entirely from Boric Acid.  It dissolves readily in the spray tank and has excellent wetting and adhesion properties.  B-17 is mildly acidic and requires no buffering agents or adjuvants for activation.  Recommended rates are 3-5 lbs per acre with a maximum for most crops of 6 lbs per acre per season.


Plant Availability and Hydrolysis Factors

Boric Acid and Solubor are both commonly used as a source of Boron in nutritional sprays. Although it is not as water soluble as Solubor, Boric Acid is the preferred source for Boron.  It is neutral in pH, does not require buffering, and does not contain Sodium.  But the primary reason for its preferred status is simple: Boric Acid is the most efficient form of Boron because plants absorb and utilize Boric Acid directly both through the roots and through the leaves.

Claims that Solubor converts immediately to Boric Acid when it is dissolved in water are open to question.  Sodium Borate, the chemical form of Solubor, is not the sodium salt of Boric Acid.  It is Disodium Tetraborate.  The dissimilarity is evident in the following comparison:


Molecular weight = 61.84.  Contains 17.5% Boron, 0% Sodium.

HO – B – OH



SOLUBOR (Borax, Sodium Tetraborate): Na2B4O7

Molecular weight = 201.27. Contains 20-22% Boron, 21-23% Sodium.

O = B – O – B – O – B – O – B = O

\           \

ONa      ONa

Boric Acid and Borax are both naturally occurring minerals.  For Solubor (Borax) to be converted to Boric Acid, it must undergo the following chemical hydrolytic reaction:

Na2B4O7 + 5H2O ® 2 H3BO3 + 2NaH2BO3

The conditions under which this specific reaction occurs have not been demonstrated, and there is conflicting evidence that it occurs in aqueous solutions at all.  Plant enzymatic reactions are probably required to degrade this molecule to its useful form.  W.L. Lindsay, Colorado State University, makes the following statement: “B fertilizers of the form B4O7= are expected to hydrolyze to H3BO3”  (Micronutrients in Agriculture, SSSA, p. 54).  His reference is to soil applications where there are ample microorganisms to assist in this hydrolysis.  In other words, it is assumed that hydrolysis of Borate to Boric Acid takes place but there is no known mechanism through which this conversion occurs.  Technical bulletins from U.S. Borax Co. indicate that aqueous solutions of Borax (Sodium Tetraborate) are stable.  They also indicate that Boric Acid occurs in Borax (Borate) solutions only when the two chemical forms have been physically mixed together.

The bottom line remains the same: Boric Acid will always be the preferred source for Boron in nutritional sprays.



Tree Fruit and Nut



 1-2 qt./acre                  Tech-Flo Mn-15

1-2 qt./acre                  Tech-Flo Zeta Zinc 22

1 pt./acre                      Tech-Spray Copper

1-3 pt./acre                  Tech-Spray Hi-K or ZnPK

½-3#/acre                    Tech-Gro B-17

5#/acre                         Lo-Bi Urea


Tech-Flo Mn-15          0-7-0               15% Mn

Tech-Flo Zeta              0-0-0               22% Zn

Tech-Gro B-17            0-0-0               17% B

Tech-Spray Copper     0-10-0             2.5% S, 5% Cu

Tech-Spray Hi-K        0-26-28

Tech-Spray ZnPK       0-16-9             1% Zn

The above recommendation may need to be modified based on current in-season tissue and/or soil analysis results, cost/market value considerations or cultural practice needs.

  Always read and follow all label directions before spraying.