Hydroponic AB Mix Calculator

For the AB Mix stock solutions commonly sold in Indonesia, the dose is usually 5 ml of solution A plus 5 ml of solution B per 1 liter of water. The exact figure depends on the product strength and the crop target EC. Measure the EC of the diluted solution with a meter, then enter the result in the calibration field in the calculator so the dose is right for your product.

Solution A contains calcium, solution B contains sulfate and phosphate. While concentrated, the calcium reacts into calcium sulfate and calcium phosphate, which settle out and cannot be taken up by plants. White precipitate at the bottom of the tank almost always comes from this mistake. The two may only meet once each of them is diluted in the reservoir.

Lettuce grows well at EC 0.8 to 1.2 mS/cm. On a 500 scale TDS meter that is 400 to 600 ppm, while on the 700 scale it is 560 to 840 ppm. The recommended pH is 5.5 to 6.5. Ranges for other crops are in the reference table on this page.

A TDS meter does not measure ppm directly. It measures EC and multiplies it by a factor. Cheap meters usually use the 500 scale, some other brands use 640 or 700. The same solution can read 1000 ppm on one meter and 1400 ppm on another when the contents are exactly the same. So record EC, not just ppm.

Only by adding fresh water, never by adding any fertilizer. The correction fields in the calculator work out how many liters of water to add. Remember that the reservoir volume rises too, so make sure there is still capacity. Add it in stages, stir, then measure again.

The main ingredients are Calcium Nitrate, Potassium Nitrate or KNO3, MKP or Mono Potassium Phosphate, and Magnesium Sulfate, known as Epsom salt. The balancer is Potassium Sulfate, sometimes with ammonium sulfate added. For micronutrients you use Fe-EDTA, Manganese Sulfate, Zinc Sulfate, Copper Sulfate, Borax, and Sodium Molybdate. All of them are available at farm supply shops and domestic online marketplaces.

Tank A holds Calcium Nitrate, Potassium Nitrate, and chelated iron. Tank B holds MKP, Magnesium Sulfate, Potassium Sulfate, and the micronutrients other than iron. This split keeps calcium from meeting sulfate and phosphate while they are still concentrated. The calculator already separates them in the result table.

Double the per-liter dose. For lettuce with a target EC of 0.8 to 1.2 mS/cm, 2 liters of water needs about 3.3 to 5 ml of stock solution A plus 3.3 to 5 ml of stock solution B. For hungrier water spinach or mustard greens, about 6.3 to 8.3 ml of each.

That dose holds if your stock solution gives EC 2.4 mS/cm at 5 ml per liter, which is the most common on the market. A volume as small as 2 liters is hard to measure with a kitchen cup, so use a 10 ml needleless syringe. Half a milliliter off at this volume already shifts the EC a fair way.

AB Mix is two concentrated solutions of fertilizer salts dissolved in water. Solution A holds Calcium Nitrate as the source of calcium and nitrogen, Potassium Nitrate, and iron in chelated form such as Fe-EDTA. Solution B holds MKP as the source of phosphorus, Magnesium Sulfate or Epsom salt, Potassium Sulfate, and micronutrients in the form of Manganese Sulfate, Zinc Sulfate, Copper Sulfate, Borax, and Sodium Molybdate.

There is nothing secret in it. What separates one brand from another is only the ratio of each ingredient and the purity of the fertilizers. That is why you can make AB Mix yourself, and the whole composition is laid open in the calculator on this page.

All three are fast-growing leafy greens that tolerate a fairly concentrated solution. The target EC is 1.5 to 2.0 mS/cm, equal to 750 to 1000 ppm on a 500 scale TDS meter. The dose is about 3.1 to 4.2 ml of stock solution A plus 3.1 to 4.2 ml of stock solution B for each liter of water.

Start at the lower limit when the seedlings have just been transplanted, then raise it in stages once the roots push through the media. Water spinach that is harvested several times usually wants the EC a little higher each time new shoots appear.

Every type of lettuce is kept in the same range, EC 0.8 to 1.2 mS/cm. On a 500 scale TDS meter that is 400 to 600 ppm, on the 700 scale it becomes 560 to 840 ppm. Romaine, green leaf, curly leaf, and red leaf lettuce do not ask for different figures.

What really differs between types is their sensitivity to temperature, not the nutrient strength. Red leaf lettuce holds its color better on cold nights, and romaine turns bitter faster if the solution is left too concentrated in hot weather. If the leaves start to taste bitter, lower the EC to the bottom of the range, not the other way around.

Source water is best below 200 ppm on the 500 scale, or EC below 0.4 mS/cm. Well water in many areas sits at 100 to 300 ppm, and municipal tap water is often higher. Above 400 ppm the room left for fertilizer gets narrow, especially for lettuce, whose target is low.

The thing to understand is that the source water EC is already counted before a single drop of fertilizer goes in. The calculator on this page subtracts the source water EC from the target EC, so the dose it gives already accounts for it. If your water is very high, filter it with RO or blend it with rainwater collected clean.

You can, but the result is not AB Mix and cannot be worked out with this calculator. Liquid organic fertilizer from livestock manure, leachate, or fermented kitchen waste supplies nutrients in a form that bacteria still have to break down first. The content changes from batch to batch and a TDS meter does not read it as available nutrients.

If your aim is to cut costs, the more measurable route is blending your own from single fertilizers. The ingredients are still mineral salts, as in factory AB Mix, the price per liter of solution is far lower, and every element can be worked out down to ppm. That is what the Blend Single Fertilizers mode on this page does.

No. All the calculation runs in your browser. This website is a static page with no database, so no numbers are sent or stored anywhere.