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# Switching From Liquid Nutrients to Dry Salts: How to Mix GreenPlanet’s Horti Line

A jug of liquid nutrient is mineral salts that were dissolved in water before the jug was filled. When you buy it, you pay for that water and for trucking it to the store. Dry nutrients leave the water out. You buy the minerals in a bag and add the water in your own grow room, which is a big part of why commercial growers feeding large rooms are moving to them.

The switch changes how you mix. You weigh out the salts, dissolve each product in its own pail, and add the pails to the reservoir yourself. Justin Cooper, co-founder of GreenPlanet Nutrients, says the biggest mistake people make in that routine is rushing it: pouring the premix into the reservoir without letting it sit for a few minutes first. A grower who has only poured from a bottle has never had a reason to wait, and the reason comes down to what the salts are still doing after they disappear into the water.

GreenPlanet built its Horti Commercial Line for growers making that move. The line is five bags of dry, fully soluble fertilizer, and you only ever mix two of them at a time. We filmed a tutorial on the line with Justin and Sara Boon of GreenPlanet, and the method in this article comes from that session and from GreenPlanet’s own Horti feed chart.

## Why commercial growers are moving from liquid to dry nutrients

When Sara asked Justin why commercial growers are choosing dry nutrients over liquids, his answer was about what is inside the jug.

> “In this case, you’re just not buying water that’s been filtered and put into the product at the manufacturing.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

Water is heavy. A grower buying liquid concentrate for a large room pays to ship all of that water from the factory, and Justin points to the carbon footprint of the shipping as well as the cost. With dry nutrients, the shipment is only the part the plant uses, and the grower supplies the water at the reservoir.

## Why mineral nutrients feed faster than organics

Liquid and dry mineral nutrients share one advantage over organic fertilizers: they feed the plant right away. When Sara asked Justin what the advantages of a system like Horti are, he started with how fast cannabis grows.

> “You don’t have the opportunity to wait for a nutrient to break down and be bioavailable. You want it to be fast.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

Organic fertilizers such as blood meal hold their nitrogen in proteins and other organic compounds. Soil microbes have to break those down into ammonium and nitrate before the roots can absorb them, and that can take days or weeks depending on temperature, moisture and how active the soil life is. Mineral nutrients are already in the forms roots take up, such as nitrate, potassium and calcium, so they are available as soon as they dissolve. Justin’s other point follows from the same chemistry: salts that dissolve completely also rinse back out of the medium when you flush.

## Five bags, two at a time

The Horti line is five products. The three numbers on each bag are its NPK, the guaranteed amounts of nitrogen, phosphorus and potassium, in that order.

- **Horti Grow**, 8-11-21 plus magnesium, sulfur and micronutrients. For vegetative growth.
- **Horti Bloom**, 5-15-26 plus magnesium, sulfur and micronutrients. For early and mid flower.
- **Horti Late Bloom**, 0-24-26 plus magnesium and sulfur. For the last two weeks of flower.
- **Horti Cal**, 14-0-0 plus calcium and magnesium. Paired with Horti Grow and Horti Bloom.
- **Horti Late Cal**, calcium and micronutrients with no nitrogen. Paired with Horti Late Bloom. Justin describes it as “multiple forms of calcium.”

Five bags on the floor can look like a complicated program, but the stage of the crop tells you which two you need, and you never use more than two at once:

- **Veg:** Horti Grow and Horti Cal
- **Early to mid flower:** Horti Bloom and Horti Cal
- **Late flower, the last two weeks:** Horti Late Bloom and Horti Late Cal

GreenPlanet’s feed chart then calls for 7 to 10 days of plain water before harvest. Our article on [whether you need to flush cannabis](https://growingexposed.com/do-you-need-to-flush-cannabis/) covers that last stretch.

Justin calls the Horti line “the steak and potatoes.” It is the base program, and growers who want to add to it can. He named GreenPlanet’s Rezin and Vitathrive as products that go on top of the base, along with others aimed at terpene profile and potency. Each bag also carries a QR code on the back that opens GreenPlanet’s feed programs and product resources on your phone, so the chart is with you at the reservoir.

The line comes in two sizes. The 50 lb bags are made for greenhouses, farms and large cultivators running stock tanks. The 5 lb bags are for hobby and craft growers, so a home grower can try salts without buying a 50 lb bag.

## What GreenPlanet leaves out of the bag

Justin says the Horti line has no anti-caking agent, no fillers, no carbonates and no food coloring. GreenPlanet’s product sheet says the same about fillers and states that the line contains “ZERO sediment or organic material to block irrigation systems.” Carbonates matter on a drip system in particular, because they can come out of solution as hard scale inside the lines and emitters.

Leaving those things out means everything in the bag is meant to dissolve and feed the plant. Justin calls the line 100% bioavailable, and he connected the claim to something most growers on drippers will recognize: the white crust that builds up on emitters, tables and the tops of pots.

> “It’s food you paid for, and when you see salt residue all over the drip emitters, all over the table, all over the top of the pots, that’s ultimately food that you paid for and is not bioavailable.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

Salts the plant does not take up stay in the root zone and push up the EC. EC, or electrical conductivity, is the meter reading growers use to measure how much dissolved salt is in a solution or in the medium. When it climbs too high, the plant struggles to take up what it needs, which growers call lockout, and Justin says the buildup does real damage to the root zone. A formula that dissolves completely also makes flushing easier, because the salts rinse out instead of staying behind. If buildup is already clogging your lines, our article on [why drip emitters keep clogging](https://growingexposed.com/why-do-my-drip-emitters-keep-clogging/) explains where it comes from.

No anti-caking agent also changes how you store the product. Horti salts are hygroscopic, meaning they pull moisture out of the air, and a grow room is humid. Close the bag fully every time you weigh from it. If moisture does get in, the salts harden, but Justin says they are still fine to use. He goes a step further and keeps each product in its own sealed bucket.

## Three ways to mix the Horti line

GreenPlanet’s feed chart covers three methods, and the right one depends on the size of the operation.

1. **Weigh out a single batch.** Measure enough salt for one reservoir and mix it in. For a grower new to dry nutrients, a single batch is the simplest place to start.
2. **Make a stock tank concentrate.** Dissolve a whole bag in a stock tank and measure out some of that concentrate each time you fill the reservoir. Justin says this is his preferred method. GreenPlanet’s procedure is to fill the tank halfway, start the mixer, pour in a full 50 lb bag (Horti Late Cal comes as two 25 lb bags), top up to the 25 US gallon mark and mix for up to 30 minutes until it is fully dissolved. Each product goes in its own tank, and the concentrate should never be stronger than 2 lb per US gallon.
3. **Run a stock tank through an injector.** An injector draws concentrate from the stock tank into the irrigation water on its way to the plants, so there is no reservoir to mix by hand. The Horti line was designed for day tank, injector and dosing systems.

## How to mix a single batch of Horti

These are the steps for the first method, weighing out one batch for a reservoir. The example is a 50 US gallon batch in early flower.

1. **Work out the stage.** The stage tells you which two bags you are using and which column of the feed chart to read. Early flower means Horti Bloom and Horti Cal.
2. **Decide how much you are making.** For most growers, the size of the reservoir decides it.
3. **Read the rate and scale it.** The chart gives grams of each product per 100 US gallons, and per 100 litres. In early to mid flower it calls for 270 g of Horti Bloom and 250 g of Horti Cal per 100 gallons, so a 50 gallon batch needs 135 g of Horti Bloom and 125 g of Horti Cal.
4. **Weigh it.** Put a container on your scale, tare it so the scale reads zero with the container on, and add product until you hit the weight. Seal the bag straight away.
5. **Dissolve each bag in its own pail.** Use at least one gallon of water for every pound of nutrient. Most growers use a five-gallon pail and a drill with an agitator bit. The salts dissolve quickly, even in cold water.
6. **Let the pails sit for a few minutes.**
7. **Fill the reservoir, stopping short of your total.** The water in your premix pails counts toward the final volume.
8. **Add the first premix, then the second.** Run the reservoir pump for a few minutes so everything is evenly mixed before you take a reading.
9. **Check the PPM and adjust it.**
10. **Set the pH last.**

## Why the premix needs a few minutes

Step 6 is the one that looks easiest to skip.

> “But this is where people make the biggest mistake. They rush to add the nutrients to the reservoir without letting it sit for a few minutes to allow for something called ionization.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

As a salt dissolves, it breaks apart into ions, the electrically charged particles of nitrogen, potassium, calcium and the rest that roots can actually take up. Justin calls that process ionization. Liquid nutrient users have never had to wait for it, because the salts in a bottle were fully dissolved before it was filled. With dry nutrients, the grower has to give the premix time to finish.

Keeping each bag in its own pail matters for a related reason. At concentrate strength, the calcium in Horti Cal or Horti Late Cal can react with the sulfate and phosphate in the other bag and form solids that fall out of solution. GreenPlanet’s directions call for separate tanks for each product “to avoid precipitation.” Those solids are nutrients your plants will not get, and they settle in tanks and lines. Diluted in a full reservoir, the two products mix without that reaction, which is why the premixes go into the reservoir one after the other and never into each other.

## Check the PPM, then the pH

PPM, or parts per million, is the number most nutrient pens show for the strength of a feed. The pen measures EC and converts it, using one of two scales. On the 500 scale, an EC of 1.0 reads as 500 PPM. On the 700 scale, the same solution reads 700 PPM. Check which scale your pen uses before you compare it with a chart, or you can end up feeding about 40 percent stronger or weaker than you meant to.

GreenPlanet works off the 500 scale. On that scale, the Horti feed chart targets 1000 PPM in veg, 800 in early to mid flower and 700 in the last two weeks. If your reading is high, add water, as long as you left room in the reservoir. If it is low, add a little more of both products at the same ratio. Once you hit the number, write down how much nutrient it took. Justin says the back and forth of adjusting should only happen once, because next time you know exactly how much to weigh.

The chart sets pH between 5.5 and 6.3. In that range the plant can take up every nutrient in the mix. Outside it, some nutrients become unavailable to the plant, and you will see slow growth or yellowing.

pH up and pH down are very concentrated and need careful handling. Wear eye protection, and never mix the two together in concentrate. Do not pour either one straight into the reservoir. Pre-dilute it first, one ounce to 32 ounces of water, then add it gradually so you do not overshoot your target.

## Less is more

When Sara asked about the most common mistakes growers make with dry nutrients, Justin answered with a joke before the real answer.

> “Yeah. They don’t buy the GreenPlanet line.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

His real answer was overfeeding. Many growers believe more food means a bigger crop, and Justin says that once a plant has been pushed too hard, it is very difficult to bring it back, even with a flush. That is why he treats the feed chart as a general guide to get you running. Every cultivar uses a different amount of food. Some plants want more than the chart, others want less, and once you know how your plants grow you can tailor it, for example by adding a little more nitrogen in veg.

> “Some plants definitely like to be fed less, and overuse is a really common problem within the industry. I always hedge on the side of less is more.”
>
>  Justin Cooper, Co-Founder, GreenPlanet Nutrients

If you get stuck, GreenPlanet has a support team you can call. Justin says you will reach a real person and get real answers about how the product works, and he added that the person might be him.

## Get the Horti Commercial Line

Growing Exposed does not sell nutrients, but GreenPlanet Nutrients does. Contact them directly, or use the links below to learn more.

Learn more about the Horti Commercial Line, its five products and its feed program at [GreenPlanet Nutrients](https://greenplanetnutrients.ca/feed-programs/horti-commercial/).

Commercial grower? Find your GreenPlanet rep. Call GreenPlanet toll free at 1-866-913-4769 or email info@mygreenplanet.com and ask who your sales rep or distributor is. GreenPlanet has reps and distributors in Canada, the United States, Australia and Europe. [Contact GreenPlanet Nutrients](https://greenplanetnutrients.ca/contact-us/)

## Common questions

### How many grams of Horti do I need per gallon?

Divide the feed chart’s rate per 100 US gallons by 100. In veg that is 3.2 g of Horti Grow and 2.5 g of Horti Cal per gallon. In early to mid flower it is 2.7 g of Horti Bloom and 2.5 g of Horti Cal, and in the last two weeks it is 2.7 g of Horti Late Bloom and 2.5 g of Horti Late Cal.

### Can I use the Horti line in soil or coco?

Yes. GreenPlanet lists the Horti Commercial Line for both soil and soilless media, which includes coco. The same feed chart, PPM targets and pH range apply in either medium.

### Can I run the Horti line through an injector or doser?

Yes. The line was designed for day tank, injector and dosing systems. Dissolve each product in its own stock tank at 1 or 2 lb per US gallon, never stronger than 2 lb. GreenPlanet’s feed chart lists how many millilitres of each concentrate to dose per gallon for a range of target EC readings.

### How do I find out which PPM scale my meter uses?

Check the manual or the manufacturer’s spec sheet first. If you are not sure, test a 1413 µS/cm calibration solution, which has an EC of about 1.4. A pen on the 500 scale reads about 700 PPM, and a pen on the 700 scale reads about 980 to 1000.

### Where do I find the Horti feed chart?

Scan the QR code on the back of any Horti bag. It opens GreenPlanet’s feed programs and product resources. The full chart, with rates for reservoirs and stock tanks, is also on the GreenPlanet Nutrients website.

## Watch the full video

Sara Boon of GreenPlanet takes Justin Cooper, GreenPlanet’s co-founder, through the five Horti Commercial Line products, the three ways to mix them and growers’ most common questions. About 12 minutes.