Making Your Own Hydroponic Nutrients

In 2016, we released a video showing you how you can start Making Your Own Hydroponic Nutrients. One of the most popular videos we’ve ever created; six years later, this video is still surprising us with how many views it gets! But it honestly makes sense. Who doesn’t love a guide that shows you how to save a lot of money so you can continue to enjoy your hobby! 

However, while videos on how to grow fruits and vegetables are an irreplaceable tool for many, for some, for whatever reason, they just don’t work. If you’re one of those people, we’re hopeful that we have the solution for you — no pun intended.

We are happy to present Chilled’s written Step-by-Step Guide to Making Your Own Hydroponic Nutrients at home. 

Basic Hydroponic Nutrient Formula

Our basic formula consists of three dry fertilizers that come together to provide a well-balanced nutrient profile for our crops.

The goal of this formula is for it to replicate the highly concentrated liquid fertilizers you can find in garden centers. To do that, we are creating separate two formulas: Part A and Part B. This will allow us to store these fertilizers for long-term use.

You don’t have to use the following fertilizers in this way. When looking to create a single round of irrigation that’s used fairly quickly, you can simply mix all three directly into a single container of water — instructions below. 

For our Hydroponic Nutrient formula, we are using the ever-popular Masterblend Fertilizer Recipe Combo Kit: 

Masterblend 4-18-38 Tomato Special will provide our plants with the widest range of nutrients. In fact, this fertilizer can be somewhat used solely where the other can’t. However, there is very little nitrogen and magnesium in this fertilizer and no calcium and sulfur. If you want a general formula that works for all your crops, you’ll need to add the other two fertilizers. 

Epsom Salt will provide additional magnesium and sulfur. The company Masterblend does not manufacture Epsom Salt. Instead, they outsource to Powergrow for it. You don’t have to use Powergrow’s Epsom salt. But while all Epsom salt is composed of magnesium and sulfate, the ratio can vary, and there are different grades for human and agricultural use. Powergrow’s Epsom salt is 16% magnesium oxide, 9.7% magnesium, 32% sulfate, and 12.8% sulfur. 

Calcium Nitrate (15.5-0-0) delivers calcium and nitrogen. Again, Masterblend does not produce their own calcium nitrate, relying on Powergrow, but you don’t have to use there’s. Powergrow’s calcium nitrate is 15.% nitrogen (14.5% nitrate nitrogen & 1% ammoniacal nitrogen), 19% soluble calcium, and less than 1% chlorine. 

Chilled’s General Purpose Recipe:

Part A Solution:

• 1-gallon Reverse Osmosis (RO) or distilled water
• 600 grams Masterblend 4-18-38 Tomato Special
• 300 grams Epsom Salt
• 1.5 grams Sodium Benzoate as an anti-mold and anti-fungal preservative (optional)

Part B Solution:

• 1 gallon RO or distilled water
• 1,100 grams Calcium Nitrate*

*This is about twice as much Calcium Nitrate as you’ll find in the traditional Masterblend formula, which is 2 parts Masterblend 4-18-38 Tomato Special, 1 part Epsom Salt, and 2 parts Calcium Nitrate. 

Formula’s Specifics

The above makes 250x concentrate (each gallon of concentrate would make 250 gallons of working solution) when using it at 15ml Part A and 15ml Part B for each 1 gallon of water.

With RO water you would get an EC of about 2.0 or PPM of 1000 at the 500 conductivity scale (.5 conversion).

Working Strength Nutrient Breakdown (Approximate)

Based on the 500 conductivity scale:

• Nitrogen – 203 ppm
• Phosphorus – 50 ppm
• (K)Potassium – 200 ppm
• Magnesium – 45 ppm
• Calcium – 220 ppm
• Sulfur – 50 ppm
• (Fe)Iron – 2.5 ppm
• Zinc – 0.63 ppm
• Boron – 1.27 ppm
• Copper – 0.63 ppm
• Molybdenum – 0.063 ppm
• Manganese – 1.27 ppm
• Chlorine – 12.7 ppm

Traditional Masterblend Single Use Formula

One Gallon Recipe: 

• 1 gallon RO or distilled water
• 2.4 grams Masterblend 4-18-38 — dissolve in water 1st
• 1.2 grams Epsom Salt — dissolve in water 2nd
• 2.4 grams Calcium Nitrate (15.5-0-0) — dissolve in water last

Step-By-Step

Creating your own liquid nutrients from granular fertilizers is a great way to save money, increase shelf-life, and manipulate your nutrient formula, e.g., NPK, without having to buy additional fertilizers!

Prep Materials

• Gloves
• Mixing Bucket
• Water (preferably heated above room temperature)
• Measuring cups, beakers, or scale
• Mixing/agitating unit like a paddle
• Near boiling water, if using sodium benzoate

Mixing Part A

1. Mix 600 grams Masterblend 4-18-38 Tomato Special into 1 gallon RO water. Pour closely and slowly over the water as the dusty powder tends to bloom and poof up. Mix thoroughly, agitating the water until cloudy water becomes easier to see through and the solids appear completely dissolved.

2. Mix in 300 grams Epsom salt, and once again, mix until solids appear fully dissolved.

3. Optional – To dissolve sodium benzoate, near-boiling water will greatly help and is almost needed. To do this, simply mix 1.5 grams of sodium benzoate into a separate container filled with about 10-20 ml of hot water. Once dissolved, simply mix the sodium benzoate solution into your Masterblend/Epsom salt solution.

• While incredibly helpful in discouraging fungal growth in your solution, please handle sodium benzoate with extreme care and ensure it’s out of reach of kids and animals.

Mixing Part B

1. Mix 1100 grams of the Calcium Nitrate into 1 gallon RO water and agitate until it appears nearly dissolved. Filled with the most impurities, Calcium Nitrate doesn’t typically fully dissolve like the other two fertilizers.

• To combat the impurity issue, you can let Part B formula stand overnight before mixing it with Part A. In the morning, you’ll notice the impurities have mostly settled at the bottom. Slowly pour Part B into an empty container, carefully ensuring the impurities at the bottom don’t tag along.

Mixing Part A and B

There are several two ways to mix Part A and B together. For both applications, mix A and B in equal parts. 

Option #1: For short-term storage of up to a week, Parts A and B can be directly mixed and then diluted with clean water to the preferred EC/PPM amount before application. 

Option #2: For long-term storage, Parts A and B should remain separate to avoid calcium from crystalizing. Before application, take a container of clean water and mix in desired amount Part A and B in two separate steps. Based on our formula strength, 15 ml of Part A and 15 ml of Part B mixed into 1 gallon of water will give you a solution strength of approximately 1000 ppm or 2.0 EC.

Hydroponic additives such as amino acids and seaweed blends can be added at this point, then pH can be adjusted to the desired range. 

Adjusting Your Hydroponic Formula

While designed for hydroponic systems and inert soilless mediums like coco coir, the Masterblend 3-piece combo works well for crops in the ground and soil mixtures. Because these media are almost guaranteed to have nutrients in them, you may have to adjust your fertilizer formula. And even hydro growers may want to make some adjustments as well. Here are some ways you can do that!

First, unlike the traditional 3-part Masterblend formula, ours’ uses twice as much calcium nitrate due to us using reverse osmosis water. If using tap water, you may find your plants do better with the traditional formula, which uses equal parts calcium nitrate and 4-18-38 tomato special. 

Speaking of tomatoes, if only growing them and other fruit-bearing crops, you’ll most likely want to stick closer to the traditional formula due to the amount of nitrogen it also brings along even when using RO water. 

With the calcium nitrate, you most likely won’t need to go higher than what we recommend, but you don’t have to go as low as what’s traditionally used. Try 1.5 parts calcium nitrate to 1 part Tomato Special. We use a lot because the Chilled garden is about 50/50 leafy greens and fruit-bearing crops, and those leafy greens tend to use up a lot of the nitrogen in our solution. 

The other most common adjustment you might make is the overall potency of solutions A and B. When mixed, Parts A and B give you 250 gallons of working solution at 1000 ppm each. That is a lot for small gardens and those looking to experiment with their ratios. 

Last, while less common, some cultivators will manipulate how much Epsom salt they use, with some creating nutrient formulas that are equal parts Masterblend, Epsom salt, and calcium nitrate. This may be a bit too much magnesium if using RO water or a medium that lacks calcium, however.

pH Adjustments 

The pH of Part A and B together will vary, especially if using tap water. Most tap water ranges between a pH of 7 and 8, while reverse osmosis water typically has a pH range between 6 and 6.5. Calcium Nitrate will have the most apparent effect on pH. However, because it’s nitrate and not ammonium-based, nitrogen’s acidify effects won’t be as prominent. 

Any basic pH adjustment solution for hydroponic fertilizers is OK to use. pH up is most commonly potassium carbonate, and pH down is most commonly phosphoric acid. Both are completely fine to use.

Make all pH adjustments last after mixing Part A and B and any other additive you add.