What are the Pros and Cons of Liquid vs. Dry Hydroponic Nutrients?

Note: Prices shown in this article are current as of the initial publication date.

Hydroponic nutrients are available in 2 forms – liquid and dry. But which one is better? This is one of the first questions that people have when they start their hydroponic journey and it can be difficult to find a definitive answer. Unfortunately the short answer is – it depends.

Both liquid and dry nutrients have their own merits and the answer rests on your personal preferences, but we will lay the pros and cons out here for you so you can make your own decision. Before we get too far into details, though, and in the interest of full disclosure, I am a firm believer that dry nutrients are the best, so read on and forgive me if my bias comes through.

Liquid Nutrients

Liquid nutrients are readily available at hydroponic stores and even in many big box garden centers. There are MANY companies that make them and the options are seemingly endless. Liquid nutrients usually only have one or two parts and they are relatively easy to use – just measure out the amount you need, dump it in your reservoir and, voila, your plants will grow.

Liquid Nutrients, however, do have a few drawbacks. Chief among them is you’re buying a lot of water. How much water? Well, when looking at a plant fertilizer, you will typically see 3 numbers on the package. This is known as the NPK ratio and tells you the amount of Nitrogen (N), Phosphorous (P) and Potassium (K) that you are getting in the fertilizer as a percentage of the total weight. AeroGarden Hydroponic Nutrients from Miracle Gro, for example, have an NPK ratio of 4-3-6. That means of the total weight of the bottle of AeroGarden Nutrients, only 4% is Nitrogen, 3% is Phosphorous, and 6% is Potassium. What’s the rest? Well, there’s 1% Calcium, 0.5% Magnesium and a lot of water.

For reference, here are the NPK ratios of some other popular liquid nutrients:

• General Hydroponics FloraGro: 2-1-6
• General Hydroponics FloraMicro: 5-0-1
• Root Farm Base: 4-0-1
• Fox Farm Grow Big: 3-2-6

Dry Nutrients

Dry nutrients have historically been used more by professional, large-scale growers and have been less available to the home grower. In recent years, however, this has changed and there are an increasing number of dry nutrients available to home growers. Because you aren’t getting water along with your nutrients, dry formulations are much more nutrient dense and NPK ratios are much higher. Masterblend’s Tomato Formula, for example has an NPK of 4-18-38. When you add in the weight of the other essential plant nutrients contained in the mix (AKA micronutrients), over 60% of the product is plant nutrition. The remainder is elements that keep the nutrients in a form that is readily water soluble and available to plants once dissolved – and no water.

Dry nutrients also win when it comes to cost. A 2.5 kg Masterblend nutrient kit from Gecko Grow (1 kg of Masterblend, 0.5 kg of Magnesium Sulfate, 1 kg of Calcium Nitrate) yields 440 US gallons (over 1,600 litres) of full strength nutrient solution for just $44. To get the same amount from Aerogarden, you would go through 6 litres of liquid concentrate. Today’s price on Amazon for Aerogarden nutrients is $35 per litre, so you’ll spend $210 to get the same amount of plant nutrition as a $44 Masterblend nutrient kit from Gecko Grow.

The main criticism of dry nutrients is that they can be harder to use. Rather than measuring by volume, it is usually recommended to measure by weight. That means you need to pull out the kitchen scale and measure out your nutrients when it’s time to use them and then dissolve them into your system in the right order. It can seem like an extra step, but after making the switch, most growers agree that it isn’t as much of a barrier as they first thought. You can also add water to make a liquid concentrate yourself using the recipe in this article.

Another thing to watch out for when selecting dry nutrients is solubility. If you have any pumps or sprayers in your system, you will want a dry nutrient that is 100% water-soluble with no fallout, or you may have nutrient particles clogging your system. Masterblend nutrients are guaranteed to be 100% water soluble with no fallout, so you can safely use them in any system.