Hydro Meal Planning 101
Every garden is unique, so a one-size-fits-all nutrient scheme isn’t always the best for hydroponic setups. In this article, Eric Hopper lays out the basics of how to design a feeding regimen that’s perfect for your plants.
Hydroponic horticulture is one of the most efficient and productive ways to grow plants. A hydroponic garden’s accelerated growth rates are fueled by the combination of the maximization of available nutrients and the delivery of oxygen to the roots. In other words, hydroponic gardening supplies a plant with everything it needs when it needs it, and the plant is therefore able to achieve optimal growth.
The nutrients delivered to the plants via the hydroponic system are the main catalysts for faster growth. Hydroponic nutrients differ from organic compounds in the soil in that they are already broken down into a form that can be easily and quickly absorbed by plants. Providing the plants with essential elements and maintaining the proper nutrient concentration are both crucial when trying to maximize the overall performance of a hydroponic garden.
There is a plethora of hydroponic nutrients and nutrient additives available to hydroponic horticulturists. In fact, it can be downright overwhelming for a newbie to wade through all the information about each individual fertilizer. The good news is a gardener does not need a degree in chemistry to build an effective hydroponic feeding regimen. A general knowledge of how the nutrients are labeled, the various types of nutrients available, and when to use what type of nutrient is all a grower needs to build a successful fertilizer regimen.
Labels on Hydroponic Nutrients
One of the first things a grower will notice when he or she goes to purchase a hydroponic nutrient/fertilizer is the various numbers and ingredients listed on the label. There are federal regulations in place that dictate how and what must be included on a fertilizer label. Aside from the brand name and the name of the registrant or licensee, each hydroponic nutrient label will contain the grade, the guaranteed analysis, and the product derivatives.
The grade is essentially the abbreviated representation of the guarantees for total nitrogen (N), phosphorus (P), and soluble potassium (K). These numbers are always separated by a hyphen. For example, if a fertilizer’s N-P-K is 20-20-20, the 20-20-20 is considered the grade on the fertilizer label. The grade gives growers the ratio between the three key nutrients found in the fertilizer.
The guaranteed analysis is the listed breakdown of percentages of elements contained in a fertilizer. The guaranteed analysis includes the available percentage of nitrogen, phosphate, soluble potash, calcium, magnesium, sulfur, boron, chlorine, cobalt, copper, iron, manganese, molybdenum, sodium, and zinc. Nitrogen is usually broken down further into the total percentages of ammoniacal nitrogen, nitrate nitrogen, and other determinable forms of nitrogen.
Most hydroponic nutrient manufacturers will include a derivative statement on the fertilizer label. The fertilizer’s product derivatives are usually listed right below the guaranteed analysis. The product’s derivatives can appear as a name of a chemical compound (e.g. ammonium nitrate) and/or as an organic ingredient (e.g. bat guano).
Start with a Base Fertilizer
The first thing a hydroponic gardener needs in his or her feeding regimen is a base fertilizer. The base fertilizer is exactly what its name implies: a foundation for the entire feeding regimen. Base formulas contain all the essential elements, which means they have all of the elements needed for basic survival and general health. Most base fertilizers are split into “grow” and “bloom” formulations, with their nutrient ratios specific to that particular stage of growth. Put another way, the grower will need “grow” base fertilizers for the vegetative stage of growth and “bloom” base fertilizers for the flowering stage of growth. There are a wide variety of base nutrients available in one-, two-, or three-part formulas, all of which contain the essential building blocks for plant nutrition. Although base fertilizers are generally labeled as such, a grower could examine the label to figure out the grade of the fertilizer and, from that, determine what type of fertilizer it is. Quality base fertilizers will contain a substantial amount of N-P-K along with a variety of micronutrients.
Don’t Forget the Calcium
Calcium is a vital nutrient for plant health and a tricky aspect of the base formula. Most base fertilizers contain only a small amount of calcium because it is assumed that the gardener’s water supply will contain calcium. A grower who has little calcium in his or her water supply or who is using reverse osmosis water may need to add a specific calcium supplement. Although calcium supplements are generally sold separately from the actual base fertilizers, it is so important to basic plant functions that a grower should considered it as part of the base formula for a feeding regimen.
In general, the feeding regimen’s nutrient additives should be considered icing on the cake. Although nutrient additives can make a big difference in the performance of a garden, they are not as important as establishing a good base fertilizer. It is only after a solid base fertilizer is established that a grower can truly reap the rewards of nutrient additives.
Additives are designed for more specific functions. For example, during the vegetative stage, many hydroponic gardeners like to supplement root enhancers. These root enhancers will not only increase the structural integrity of the plant (which better prepares it for large fruits or flowers), but will also aid in keeping the roots healthy in the hydroponic system. Most root enhancers are enzyme formulas or microorganism-based supplements designed for use in the vegetative and early flowering stage. Some, however, some can be used throughout the entire life cycle of the plant. Additives that contain natural growth hormones, such as kelp, are another popular choice for the vegetative stage of growth.
A hydroponic gardener can’t walk into a hydroponic retail shop without seeing a few different flowering or blooming nutrient additives. In fact, there are so many specific additives for the fruiting/flowering stage that they can be categorized into three groups: flower initiators, mid-flowering additives, and ripening additives. Many hydroponic growers will use a combination of blooming additives as the fruiting/flowering stage progresses. Flower initiator additives help the plants quickly transition from vegetative to flowering growth. Mid-flowering additives are designed to be used during the mid-stages of flowering. Finally, ripening additives are designed for use in the later stages of flowering to, as the name suggests, help accelerate the ripening process and boost yields.
Other additives that hydroponic growers commonly incorporate into their feeding regimens to help maximize performance include carbohydrates, enzyme formulas, amino acids, humic/fulvic acids, beneficial microbes, and vitamins.
The best way a grower can determine which additives to use along with his or her base fertilizer is through experimentation. This can be a time-consuming venture, but at the end of their grow cycles, horticulturists will be able to determine which additives helped them meet their goals and which did not. A good parts per million (ppm) or electrical conductivity (EC) meter are must-have tools for hydroponic gardeners experimenting with building a feeding regimen and can help the grower keep the nutrient solution within a desired range of nutrient concentration.
Although most pH buffers are not actually nutrients and will not contribute to the nutrient content of the solution, they are still necessary when building a successful feeding regimen. For plants to be able to uptake nutrients from the solution, the pH needs to be kept in a particular range. For most hydroponic systems, a pH of 5.5-6.2 is ideal for nutrient uptake. As the pH fluctuates farther away from the desired range, specific nutrients will become unavailable to the plant. Over time, this can cause a series of problems, including nutrition lockout and/or nutrient deficiencies.
Building a customized hydroponic nutrient regimen is like making your own unique recipe for gardening. A base nutrient will provide the plants will everything they need to survive, while nutrient additives are designed to help the plants thrive during particular stages of growth. As with other aspects of gardening, building an optimal fertilizer regimen requires experimentation. However, one of the exciting aspect of becoming a hydroponic grower is this honing-in on the specific nutritional needs of your plants. Every garden is different. Sure, every garden shares the same basic needs, but the growing space, the grower, and the plants themselves make each situation unique. Over time, these slight adjustments to a feeding regimen will equate to faster growth rates, increased quality, and more consistent yields.
Written by Eric Hopper | Writer, Consultant, Product Tester
Eric Hopper’s past experiences within the indoor gardening industry include being a hydroponic retail store manager and owner. Currently, he works as a writer, consultant and product tester for various indoor horticulture companies. His inquisitive nature keeps him busy seeking new technologies and methods that could help maximize a garden’s performance.