If you grow hydroponically, you must use nutrients as the water alone is not enough to sustain plants’ growth. Without nutrients, your hydroponic vegetables and herbs will die quickly. Which nutrients to use and where to find them should be your first problem that we are ready here to solve!
The most common nutrients for hydroponics are fertilizers containing mainly nitrogen, phosphorus, and potassium in liquid and dry form. Vegetables grown in hydroponics need an increase in nutrients during the vegetative and fruiting stages. The so-called complete fertilizer is an ideal choice for hydroponic gardening.
One of my first concerns in choosing hydroponic nutrients is its form. Are liquid nutrients cheaper than dry? Which is easier to use? Which has a longer shelf-life? Are they both effective in herbs and veggies? Here is my experience on them!
Table of Contents
- 1 Hydroponic Nutrients and Their Form
- 2 Dry vs Liquid Hydroponic Fertilizer
- 3 When To Use Hydroponic Nutrients?
- 4 How to Mix and How Much Hydroponic Nutrients Should You Use?
- 5 Relationship of Nutrients to Crop Type and Stages
- 6 What Hydroponic Nutrient to Use Based on Crop
- 7 When To Use Hydroponic Nutrients (Seedling vs Growing vs Flowering)
- 8 What are Additives in Hydroponics?
- 9 How to Monitor Nutrients in Your Hydroponic Solution?
- 10 Sources
Nitrogen, phosphorus, and potassium are the three macronutrients. These are present, in different proportions, to the plant food that needs to be provided. Such nutrients, if used in balance and at the right time will ensure leaf development, structure, flowering, and fruiting.
Hydroponic water itself does not provide any nutrients. Your plants need nutrients to be added to the water (that acts as a vehicle) and they are delivered to the roots. Thus, making sure that your plants are getting sufficient and right nutrients is the wisest thing a hydroponic gardener does.
Generally, nitrogen is responsible for leaf development. It is a major component of chlorophyll, which makes leaves green in color. More importantly, they are also a major component of amino acids.
Amino acids build up proteins that are an essential part of plant genetics, cell structure, and even enzymes that work for biological processes. Thus, the lack of proteins will result in wilting, and worse, death.
Now, I hope you already get why nitrogen is essential. In short, without it, life will not exist.
Phosphorus stimulates root development, makes plant structure stronger, enhances flowering and seeding, and heightens vegetables & herbs quality.
Like nitrogen, phosphorus is also a valuable part of biological processes as it is involved from rooting to harvesting.
Potassium is the nutrient that provides plants with the defenses needed to fight disease. This macronutrient affects color, size, shape, and even seed quality.
Worried about the immunity of your hydroponic crop? This nutrient could be your best friend! Not by accident is indeed called the “quality” nutrient. With these benefits, potassium is mobile and can be transferred from older plant tissues to younger ones.
For hydroponic systems, the nutrients come in premixed liquid form and dry form. Liquid nutrients can be applied directly while dry nutrients need to be appropriately mixed in the right amount and dissolved in the water tank.
Perhaps, that one question in your mind right now is: Which one is better for me?
Generally, hydroponic dry nutrients are cheaper than liquid ones also because they may be shipped in bulk.
Indeed, liquid nutrients for the same amount of plant nutrients use way more space thus increasing the shipping fees.
In terms of shelf-life, dry hydroponic nutrients last longer at parity of storing conditions.
I can attest to this since I bought both liquid and dry nutrients last year. Just after 5 months, the unused liquid nutrient already faded in color, which is a sign of degradation. Whereas, the dry nutrients are still good as of today!
However, handling of dry nutrients is also critical. You should store it in air-tight containers because they are prone to absorbing water from the air.
Liquid hydroponic nutrients are way easier to use compared to their dry counterparts.
Why? Because they are pre-mixed, thus all you need to do is to measure, mix them with your water, and you are good to go.
On the other hand, dry nutrients, most especially if bought in bulk and separately, need an additional step—computation. This will be clearer as we move forward.
In hydroponic systems, bountiful harvest depends on how you nourish your water. To do this, choose fertilizers having high nitrogen amounts during the early stages. While on flowering and fruiting, eye for phosphorus and potassium-rich nutrients.
When shopping online, most of the liquid and dry hydroponic nutrients come in pairs (i.e. Part A and Part B) or threes. This is necessary because nutrients have different chemical properties like solubility that would not be optimized if mixed as one.
Liquid hydroponic nutrients are easier to use as can be added, as they are, to the hydroponic system.
Examples of this are Humboldts Secret and the Flora Series Nutrients, both are available on Amazon and are common choices. Let me first discuss Humboldts Secret.
Humboldts is a 2-part hydroponic nutrient. This nutrient holds the principle we just discussed a while back. Part A (4-0-1) and Part B (1-4-2) must not be mixed simultaneously into water because a precipitate can form. In order for you to visualize them better, they look like bulks of solid powder. We do not want that!
For this nutrient, you need to use 5-9 ml/gallon in the first 4 weeks. Then, you will increase this amount to 9-14 ml/gallon in the first 6 weeks of flowering. The amount will then be decreased to 7-10 ml/gallon in the next weeks until fruiting.
On the other hand, the Flora Series is 3-part. FloraMicro® is optimized for growing and blooming cycles, FloraGro® is used during the vegetative stage to produce strong roots, while FloraBloom® is for the flowering and fruiting stages. Below is a detailed guide on how to use this product according to its manufacturer.
If you want an easier way on how to use this product, let us base it on a recommendation of a 2-year patronizer of this product. During the growth stage, he uses 1 tsp of FloraMicro®, 2 tsp of FloraGro®, and 1 tsp of FloraBloom®. While for the flowering stage, he uses 1 tsp of FloraMicro®, 1 tsp of FloraGro®, and 2 tsp of FloraBloom®.
For dry nutrients, it is needed to dissolve each nutrient separately. Nutrient A must be dissolved and stirred first, followed by nutrient B in the same container.
If you are growing tomatoes or other fruiting veggies, this fertilizer may be the one for you. Why? Masterblend (4-18-38) contains more amounts of phosphorus (18) and potassium (38) which are beneficial in ensuring crop harvest quality.
This product usually comes with additives namely calcium nitrate and magnesium sulfate. These will also be added to your nutrient solution for best results.
You can find pre-mixed masterblend like this on Amazon which contain 12 grams of the nutrient to be dissolved in 5 gallons of water. It also comes with 12 grams of calcium nitrate and 6 grams of magnesium sulfate, each to be dissolved in 5 gallons of water.
But if you are someone like me who wants to save more by buying in bulk, prepare to weigh. Since we do not want you to worry about calculations anymore, we already did that for you.
For masterblend, you will use 2.27 grams per gallon. This means if you have a 10 gallon bucket, all you need to do is multiply these values. Furthermore, you will need 1.70 grams of calcium nitrate and 1.13 grams of magnesium sulfate per gallon of water.
Go Grow Planters is another pre-mixed option that you can find on Amazon. The advantage for this one is that it already has the 16 macronutrients and micronutrients. No need for additives!
Each packet is already labeled with what volume of water (i.e. 3.5 gallon and 5.5 gallon) should the nutrients be dissolved. Another win is that through its special formula, you do not need to measure pH and electric conductivity anymore. Both are relevant factors in hydroponic nutrient management.
Crop types and growth stages are two factors that need to be considered in applying nutrients. For instance, the nutrient needs of lettuce is different from that of tomato. Moreover, nutrient consumption in the fruiting stage is far way different from the seedling stage.
Leafy vegetables need more nitrogen. In the first part, we noted that nitrogen is responsible for leaf development.
If you are growing hydroponic lettuce, chinese cabbage, bok choy, or kale, you might need to look for nitrogen-rich options. These are nutrients with higher first numbers like 21-0-0 or 15.5-0-0. Another safe and easier option is to go with complete nutrients such as Envy, Flora Series, Masterblend, and Go Grow Planters.
Fruiting vegetables need the complete nutrients. Fertilizer labels you may be looking for must be like 9-3-6 or 3-12-6. There must be no zero in the labels! Thus, the masterblend (4-18-38) brand will be a good choice for crops like tomatoes, pepper, and eggplant!
Several studies asserted that environmental factors such as water stress, salt stress, and plant nutrition affect herb aroma. Thus, hydroponic herbs usually require the right nutrients. A prominent recipe for herbs is a mix of the following in 25 gallons of warm water:
- ½ ounce of potassium phosphate
- 2 ounces of potassium nitrate
- 3 ounces of calcium nitrate
- 1 ½ ounces of magnesium sulfate
- ½ pint of iron sulfate
- ½ pint of boric acid
- ½ teaspoon of zinc sulfate
- ½ teaspoon of copper sulfate
Generally, your vegetables and herbs need relatively low nutrients at the sowing stage. At this point, water is needed more than nutrients. However, it is also important to note that nutrient availability in the early stages will still affect plant development and even your yield in the long run!
However, during the growing/vegetative stage, nutrient requirements increase due to development of plant parts such as stems and leaves.
Nitrogen is the nutrient that you need to focus on at this stage. This is why I also recommend Foliage Pro during the vegetative stage. If you will recall from the previous paragraphs, a higher first number on a fertilizer label means higher amount of nitrogen.
During flower development, plant nutrient requirement decreases for a bit. But in fruit development, it heightens once again to support harvest quality.
Here is a nutrient recommended for these specific stages that you can buy on Amazon. We tackled a while back that phosphorus (the second number on every label) enhances flowering and seeding. Whereas, potassium (the third number) heightens the fruit quality.
Considering this, phosphorus and potassium-rich nutrients will optimize flowering and fruit production.
Additives are chemicals targeting specific plant growth processes. Some of these are rooting, nutrient uptake, nutrient translocation, disease immunity, and faster growth.
The nutrients that we tackled such as calcium nitrate and magnesium sulfate are considered additives. In the case of Masterblend, these are added to further provide micronutrients for growth and development. Different additives and their benefits are summarized below.
Here’s an additive that enhances rooting:
This is an additive that improves nutrient transfer, health, and immunity:
This is a booster:
Electric conductivity (EC) is a method of reliably measuring and monitoring the amount of nutrients in a nutrient solution.
Cheap EC meters can be bought on Amazon, and some even come with a pH meter—both are valuable investments for a hydroponic gardener.
Maintaining the proper EC for your crop and system is critical. Some plants, like lettuce and other greens, demand a considerably lower EC than fruiting crops, like tomatoes. For optimum development, each crop has its own appropriate EC range.
Plants will rapidly exhibit signs of nutrient deficiency if the EC is too high. A high EC causes water stress in plants. Plant wilting is the first symptom of fertilizer excess. Conversely, plants that are undernourished (low EC) will take in too much water, appear floppy, and light green.
It is critical that the EC be measured, monitored, and adjusted on a regular basis because environmental variables influence plant nutrient absorption. By doing that, you can make sure that your crop is receiving the right nutrients.
The optimal EC range for most hydroponic crops is between 1.5 and 2.5 dS/m for most crops.
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