Hoagland's Complete Nutrient Solution

Hoagland's Complete Nutrient Solution

   - Hoagland Solution 1 

   - Hoagland Solution 2 

   - Knop's solution ^[1]

Fine powder, applied for 100 L media preparation

25X Stock, liquid media, 500 ml

Applications

For use in plant cell culture and micropropagation.

Components, mg per litre

Hoagland Solution 1   

Hoagland Solution 2  

Preparation

Dissolve 2.32 g of solution 1 mixture or 2.17 g of solution 2 mixture into MQ or distilled water. Heat with continuous stirring until all are dissolved. Make the volume to 1000 ml. Adjust the medium to the desired pH using 1M HCl/NaOH and aliquot into tubes or flasks. Autoclave at 121°C for 15 minutes.

During preparation, avoid naked flames, and DO NOT mix the basal salt mixture with reducing substances such as sucrose in powder form.

Storage

The media powder is extremely hygroscopic and should be protected from atmospheric moisture.

The media powder is in a sticky status and packed in a sealed plastic bag inside a sealed aluminium bag. Please seal the bags after use.

If possible, the unused powder should be stored in a sealed box with silica desiccant and refrigerated at 2~8°C.

Note

This mixture contains a large amount of inorganic salt in hydrate form, such as Ca(NO₃)₂·4H₂O and MgSO₄·7H₂O, resulting in the media powder in a sticky state.

We recommend the user use up all the mixture when first opening the pack ^[3]. Dissolve all the mixture in double distilled water or MQ water and make 4 L of 25X stock for future use.

The 25X stock can be stored at RT (better 2-8°C) for future use, the shelf life of such a stock can be several years as all ingredients and elements are in a stable inorganic salt form.

The 25X stock is in a suspension state. After resting for a while, the precipitates monocalcium phosphate exist in an emulsion state, which will re-suspend easily after shaking, facilitating the next round of dilution to 1X stock.

When making it into a 1X working solution, water-bath the 25X stock at 40°C for 10~15 minutes is optional to achieve better suspension, shake it well, and quickly make it into a 1X solution. Autoclave at 121°C for 15 minutes.  0.22μm filtration after autoclave is an optional process to remove any remaining precipitates ^[4].

[1] To request a quote and order a customised version, please contact support@gmexpression.com

[2] We still have our old recipe with FeNaEDTA - 20mg/L. Please contact us if you would like to have this recipe.

[3] An easy way to use up the mixture is to cut the corner of the plastic bag, fill the bag with about 100~250ml of MQ water, shake the plastic bag to dissolve the basal salt and pour the solution into a beaker or volumetric flask, repeat several times until no salts left in the plastic bag. 

[4] When preparing Hoagland Solution, if the pH is near 7 (original pH 5.3-5.6), it is normal to observe a few precipitates at the bottom of the solution after autoclaving. This is mainly calcium carbonate, formed from calcium ions reacting with carbon dioxide in the air, with less calcium phosphate. Remove them by filtering, or leave them as they do not affect the experiment results.

---------------------------------

FAQ

Q: Will the choice of either medium make a significant difference to the cell growth? Is the pH of solution 1 and 2 very different?

A: The differences between Solution 1 and 2 primarily lie in the macro-elements.

Solution 2 contains ammonium and nitrate salts, which may sometimes be preferred over Solution 1, which only has nitrate salts. The ammonium ion helps delay the development of undesirable alkalinity. However, beware ammonium ion is toxic to most crop species and is rarely applied as the sole nitrogen source.

When it comes to micro-elements, molybdenum is essential for the growth of a small group of species, such as tomato plants. The differences between 0.12 mg/L Na₂MoO₄ and 0.02 mg/L H₂MoO₄ are minimal and exchange the recipe is allowed. However, considering H₂MoO₄'s solubility is relatively low, and Na₂MoO₄'s introduction of Na ions can disrupt the accuracy of comparable experiments. This is sometimes why Na₂MoO₄ is not preferred or H₂MoO₄'s is limited use. The reason for using H₂MoO₄ in Solution 2 is that it can better react with NH₄NO₃ in the solution, leading to the formation of the more soluble (NH₄)₂MoO₄, which Solution 1 lacks such convenience.

For more details, you can refer to this link. https://en.wikipedia.org/wiki/Dennis_Robert_Hoagland#Macronutrients

The pH of original 1X Hoagland Solution 1 is 5.3-5.6, the PH differences between Solution 1 and 2 is not big, Solution 2 is slightly more acid, different species have their optimal pH for growth, making pH adjustment essential before inputting the solution into culturing flasks. For example, blueberry growers need to adjust the final pH to 4-5, while some species, like granatum, require a more basic pH.