Molybdenum, despite the funny name, is essential for good nitrogen utilization in the plant. It is needed for the process that converts nitrate nitrogen in the plant into amino acids and then into complete proteins, imparting disease and insect resistance on the way. It is also necessary for the microbes responsible for nitrogen fixation in soil and in legumes. A little goes a long way! In the soil our target is the lowest of all the essential nutrients we recommend.
The molybdenum products on the market tend to come in large quantities, like 2.5 gallon jugs, suitable for larger scale agriculture to cover acres at a time. In this post we’ll show you how we made a concentrated liquid we can reach for to use in foliar feeding and in soil drenches in our home garden.
There are a lot of good reasons to make sure your plants have sufficient molybdenum.
- Moly is needed to convert nitrate to amino acids and then on to complete proteins in the plant (it’s part of the nitrate reductase enzyme). Incomplete proteins are a magnet insects and disease, so this is a biggy.
- Moly is needed for nitrogen fixation in legumes.
- Molybdate, the most common form of molybdenum in the soil, is an anion which leaches with rain and irrigation. We look at a lot of soil tests and many of them show zero moly or moly just above the detection limit.
- Moly is less available at lower soil pH. This is different from most soil mineral elements. Like phosphorus, it ties up with iron and aluminum at low pH, but unlike phosphorus, it doesn’t tie up with calcium at high pH.
- The presence of moly in the soil and plant has been shown to dramatically improve yield (ref 1).
- Legumes and brassicas have high moly requirements while tomatoes are medium and grains are low. However, even species with low moly requirements show a dramatic increase in yield when moly is sufficient in the plant.
- Sandy soils tend to be deficient in moly. Moly can increase drought resilience, another plus for adding it to sandy soils.
- Molybdenum supports the bacteria in the soil that fix nitrogen – free nitrogen from the atmosphere!
Note
Do not apply molybdenum to areas where ruminant animals might graze. Molybdenum can be toxic to ruminants.
What You’ll Need
- Sodium Molybdate Dihydrate. We buy ours from Alpha Chemicals
Note
Although sodium molybdate dihydrate is an OMRI approved input for situations where a molybdenum deficiency is documented, there are no organic approved products in powdered form. The Alpha Chemicals product we use is not approved. Check with your certifier for approved products containing moly.
- Amino acid soy hydrolysate. We use BioAg NitroMino. It is very important to store this product in a tightly sealed container. All amino acid hydrolysates absorb moisture like crazy and will turn to brick in no time if stored improperly. You can see ours as the yellow powder in the glass jar in the photo below.
- Fulvic acid. We use BioAg Ful-Power. Fulvic acid along with amino acids will lightly chelate the molybdenum and provide the carbon pathway for easy absorption by the plant. They also hold the moly in a form that is not so easily leached by rain or irrigation.
- Clean water – free of bicarbonates and chlorine compounds. It can be distilled or rain water, or reverse osmosis water, or spring water, or any water that has been tested as clean. Bicarbonates or chlorine can greatly reduce the effectiveness of the mix.
- A small, clean 8 oz bottle or jar.
- A gram scale. I put mine in a plastic bag to protect it.
- A funnel to get things into the jar.
- Gloves, a face mask and eye protection (I used my glasses).
The Recipe
- Start with 200 ml clean water in your 8 oz bottle. Note that 200 ml of water weighs 200 g.
- Use your gloves, mask and eye protection for the rest of the steps.
- Add 15 grams sodium molybdate hydrolysate using the funnel. Cap and shake the bottle to dissolve the powder.
- Add 25 grams amino acid hydrolysate. Cap and shake the bottle for 10 minutes or so to dissolve the powder. The powder likes to stick to the insides of the bottle and funnel, so this step takes a while.
- Add 25 grams of fulvic acid. Cap and shake to mix.
- Let it sit half an hour before using to make sure the moly is fully chelated.
Congratulations! You have just created a 3% molybdenum solution, chelated with about 8 times amino and fulvic acids. [How does the math work? Sodium molybdate hydrolysate is about 40% molybdenum. 15 g * 0.40 = 6 g which is 3% of 200 g water.]
Once we have our little bottle of concentrate, we can use it to create foliar sprays or soil drenches. As with the concentrate, we want to be sure we only use clean water in our foliar or drench.
A safe concentration rate is 2 tablespoon / gallon (or 8 ml / liter). This provides an overall dilution of about 240 mg Mo per liter (3% times 8/1000).
This morning I used two gallons of the diluted mix as a foliar for about 150 sq ft of cane berries about 18″ tall, plus 9 citrus ranging from 3′ tall to 10′ tall, plus three mature semi-dwarf stone fruit trees and 20 feet of passion fruit hedge. I sprayed to the point of runoff, although I wasn’t able to fully cover the semi-dwarf trees. The morning was dewy and cool and I did the spraying after it got light but before the sun came up.
My hope is that the moly with the boost of amino acids and fulvic acid will give my berries and trees some immunity against disease, plus improve their nitrogen utilization. I feel like perennials especially need a moly boost in our sandy soil, and these areas have not received moly as a soil amendment. Plus it’s fun to go out with Moly early in the morning!
This reference has a lot of non-relevant information, but near the end is a summery of yield improvement.
