Hoagland’s nutrient solution

Title: Procedure for the preparation of Hoagland’s nutrient solution for hydroponic studies

Reference: Hoagland and Arnon, 1950

Citation: Hoagland, D.R. and D.I. Arnon. 1950. The water culture method for growing plant without soil. California Agri. Exp. Sta. Cir. No. 347. University of California Berkley Press, CA., pp: 347.

Reagents: See table given below

Procedures:

Stock Solution

  1. Take 6 plastic bottles and wash them thoroughly. Label each bottle from 1 to 6 or as desired (as shown in column 1 of the table)
  2. Prepare molar solution of macro-nutrients and  mM solutions for micro-nutrients by dissolving the quantity given in the “Amount required for SS” column
  3. Put each nutrient stock solution in a separate bottle. All macro-nutrients will be combined in one bottle. Do not mix unless needed because it would precipitate quickly
  4. Store in a refrigerator at 4 oC
  5. These calculations are per liter basis. To calculate a different molarity, you will need to recalculate the given quantities

Working solution

  1. Take one liter of water (rap or distilled) in an open container
  2. Use the given quantity of stock solution from each bottle as shown in “Volume of stock solution per liter of final solution” of the table e.g. you would need 6 ml of KNO3 from bottle 1 per litter of water
  3. If you wish to prepare the half strength Hoagland’s nutrient solution, simply double the quantity of tap water (i.e. 2 L) OR use half quantity of stock (e.g. 3 ml of KNO3 per liter)

Precautions:

For stock solution

  1. Preferably use laboratory grade salts to prepare stock solutions. Commercial grade salts precipitate and yields poor results.
  2. Keep each stock solutions in a separate bottle and do not mix before use
  3. Keep the stock bottles air locked/tightly sealed
  4. Never mix concentrated stock solutions before use
  5. Never use STOCK solution if you observe any precipitation in the stock bottle
  6. The shelf life of stock solution is about 6 months unless any precipitation occur earlier

For working solution

  1. Freshly prepare working solution just before use by mixing the given quantity as shown in tables below
  2. Never apply working solution if any precipitation is observed in the dilution container
  3. Never store the working solution more than 3 days
  4. Check the pH of working solution, and if necessary adjust to pH 5.8 to 6.3 with 1M KOH or HCl. If you do not want to change the K concentration then you can use NaOH but it will add Na.

pH of nutrient solution: Depending on the nature of growing media, the pH of nutrient solution is altered over-time (mostly turns acidic). For example, in sand it goes acidic over a week or so. It may cause alterations in nutrient availability that is observed as leaf cholorsis. It is suggested to periodically replace the nutrient solution by completely draining by tap/distilled water once a week and replace with fresh nutrient solution.

Tip: If precipitation occur during addition of stock solutions to water, try adding MgSO4 at end (Bottle number 4)

Table of Elemental Concentration in Stock and Working Solutions

 Sr. # Macronutrients (M) M. Wt. M of SS Amount required for SS Volume of Stock solution per liter of final solution
Element
1 KNO3 101.1 1 101.1 6 mL/L of water
K, N
2 Ca(NO3)2.4H2O 236.16 1 236.16 4 mL/L of water Ca, N
3 (NH4)2PO4 115.08 1 115.08 2 mL/L of water
N, P
4 MgSO4.7H2O 246.49 1 246.49 1 mL/L of water
Mg, S
5 Micoenutrients (mM) (all in one bottle ) 1 mL/L of water
KCl 74.55 50 3.7275 K, Cl
H3BO3 61.84 25 1.546 B
MnSO4.H2O 169.01 2 0.33802 Mn, S
ZnSO4.7H2O 289.55 2 0.5791 Zn, S
CuSO4.5H2O 249.71 0.5 0.124855 Cu, S
H2MoO4 (85% MoO3) 161.97 0.5 0.080985 Mo
6 Fe-EDTA 346.08 20 6.9216 1 mL/L of water
Fe

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