Nutrient Buyers Guide: How To Choose The Right Nutrient For Your Hydroponics or Indoor Garden

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Choosing the right food for your plants is one of the most important decisions you can make as a grower. Don't make this decision lightly. Use this GrowersHouse guide to make an educated decision on what nutrients will help your plants reach their maximum potential. It's with carefully assembled information like this that we strive to become the best online grow store you'll visit.

In a complete diet—all the nutrients and additives your plants will consume—there are two main groups:

Here are our staff's favorite Nutrient Starter Kits:

Best overall nutrient kit: VegBloom RO/Soft Kit

• Great for coco, soil and hydroponics


• High grade ingredients, resulting in many award winning crops


• Staff recommended and used by our owner Nate Lipton

Best budget nutrient kit: Technaflora Recipe for Success Kit

• Great for coco, soil and hydroponics


• Small bottles, but will work for up to 4 plants from start to finish


• Tried and true formula by company around for decades

Best nutrients for use with hard water: VegBloom Tap/Hard Kit

• Great for coco, soil and hydroponics


• If you don't plan on using an RO filter, can be used with tap water


• Best for use when input water PPM is 250 ppm or higher

Best organic nutrients: Vegamatrix Starter Kit

• Great for coco and soil, not good for hydroponics or drip lines


• Vegamatrix is over 95% natural and organic


• Designed by Kyle Kushman

To Begin, Answer 3 Questions

Here are three important questions you should answer before buying from the GrowersHouse plant nutrient store:

Question 1: Soil, Coco Coir or Hydroponics? 

Before choosing grow room nutrients, decide on your method of growing. Choose a growth medium, such as soil, coco coir, or hydroponics. Most indoor grow nutrients are made to be used with one particular medium, and maybe with two, but only occasionally with all. For example, House & Garden has three base nutrient types: Soil, Cocos, or Aqua Flakes. A different approach is taken with Botanicare CNS17, a hydroponics nutrient that bundles two base nutrients into one bottle for use with soil or coco methods. Nutrient bottle labels typically state which media can safely accept an application of the product.

Soil: Consider its nitrogen-phosphorus-potassium levels before adding base nutrients. Every nutrient bottle is labeled with N-P-K numbers separated by hyphens: for instance, 3-4-1. The numbers always represent, in this order, ratios of nitrogen-phosphorous-potassium. They reflect the percentage of each nutrient in the fertilizer that is readily or immediately available to plants. 

The ingredients in a soil or soil/fertilizer combination influence those numbers. For instance, FoxFarm Ocean Forest potting soil contains extremely high levels of guanos and castings, so it provides plants with many of the required nutrients without the need for additives. But that bolstered level of nutrients in soil won't last because plants eventually eat all of the goodies in soil. That's when you must add supplemental nutrition. When using this particular soil we usually recommend using clean water for 3 to 5 weeks, depending on how much nutrient your particular plant uses.

Hydroponics or coco coir: For these media, you are responsible for adding all the hydroponic grow nutrients you wish your plant to eat. That's because the grow medium used in these systems is inert, and the plant obtains its nourishment only from the water-soluble indoor grow nutrients you provide.

Question 2: Organic or Synthetic (non-organic) nutrients? 

Organic nutrients work best in drain-to-waste gardens, where water drains out of the bottom of a bucket and is not reused, rather than in recirculating hydroponics systems. The reason is that organic nutrients often contain particulates big enough to clog pumps, small tubing, sprayers and misters. It is common to use organic indoor grow nutrients with soil, soilless media, and coco coir. Some companies are developing organic nutrients that they say work well with hydroponics systems, but GrowersHouse has yet to test any. 

Synthetic nutrients are the most common hydroponic grow room nutrients, including for growing the food we buy at the grocery store and eat. These nutrients for hydroponics can often also be used in coco coir and soil. Always study the nutrient label to be sure.

Another quick note about organic nutrients vs. synthetic nutrients: On synthetic nutrients, N-P-K numbers are often much higher than on organic nutrients. The reason is that synthetic nutrients are more readily absorbed by plant roots than are organic nutrients—the nutrients immediately available to the plant are higher. This does not necessarily mean there are more nutrients, just that they release faster than the nutrients in organic products.

Question 3: What Is Your Budget? 

Only you can decide your budget. Products are available in many price ranges.

One way we try to make GrowersHouse the best online grow store is to stock a deep inventory of quality products in many price ranges. Do some shopping on these Growers House pages and learn what fits your budget, then start comparing the nutrients of the products.

Additive Types

Choose your additives based on their target function. Different additives affect different plant growth phases. 

Here are some additive products for achieving different goals with your plants:

1. Flower Boosters/Bloom Maximizers

Increase the size of your yield and the density of your flowers and buds by using these additives. They can almost always be used in conjunction with any base nutrient, and are usually high in Phosphorous and Potassium (P and K). Watch for signs of nutrient burn with these plant performance boosters because they are strong in the elements mentioned. Although typically more expensive, they are arguably some of the most effective additives. Use these nutrients only in the flowering phase of plant growth. Some of the flower boosters that we recommend after good success are Bud XL by House & Garden, Big Bud by Advanced Nutrients, Hydroplex by Botanicare, Fire by Heavy 16, Bloombastic by Atami, and KoolBloom by General Hydroponics.

2. Mycorrhizae/Bacteria, Enzymes & Vitamins

Mycorrhizae are tiny fungal filaments that attach to roots, spread into the media, and gather nutrients and moisture for the plant. Mycorrhizae are attracted to plants because they enjoy the sugars the plant passes to its roots. 

The relationship between plants and mycorrhizae is natural. By adding mycorrhizae to your media—it's called inoculating because it helps plants to fight disease—you encourage this beneficial relationship. Although mycorrhizae create fungal colonies better in non-hydroponic growing environments such as soil and coco coir, some mycorrhizae are made specially for hydroponics. Among them are Great White by Plant Success, White Widow by Humboldt Nutrients, and Piranha / Tarantula by Advanced Nutrients. Mycorrhizae for use in soil and coco coir include Myco Maddness by Humboldt Nutrients, Oregonism by Roots Organics, and Mykos by Xtreme Gardening. 

Enzymes break down nutrients into small components to make them easier for roots to absorb. They work especially well with starches and carbohydrates. Enzymes often are also great for preventing the formation of pythium and algae. Some of the most popular are Hygrozyme or Sensizym by Advanced Nutrients. You can use mycorrhizae and enzymes at any time in your plant's life cycle.

Vitamins, including B-1 (thiamine), help your plants use and create carbohydrates. With carbs, your plants have enough energy to build strong vegetative growth and to power production of flowers and essential oils. B-1 also facilitates your plants' use of phosphate, which is an essential nutrient that fuels flower growth. 

Thiamine strengthens plant immune systems. It also activates Systemic Acquired Resistance (SAR). Like vaccines in humans, SAR produces an increased immune response to diseases. What's more, B-1 assists in root development so your plants take in more nutrients faster, making them more resistant to shock, transplanting and cloning.

3. Root Stimulants 

Help increase the growth rate and size of roots so your plants absorb more nutrients and grow larger, with more structural support in the roots. Root stimulants can also help if you're encountering root issues, including root rot. The unanimous favorite rooting stimulant among GrowersHouse staff is Roots Excelurator by House and Garden. A good, less expensive option is Bio Root by General Organics. Although more important in the beginning stages of your plants' life cycle, including germination and the vegetative stage, root stimulants also can be used during flowering.

4. Sweeteners

Try these additives to enhance or manipulate the taste of your flowers, fruits and buds. Use them only in the flowering phase. Some examples of sweeteners are Sweet Grape by Botanicare, Original Berry by Botanicare, Hi-Brix Molasses by Earth Juice, and Bud Candy by Advanced Nutrients.

5. Flushing Agents

Flushing your plants frees them of nutrients that built up inside them. Nutrients that you allow to remain can cause tastes that are bitter, chemical and artificial. 

If your plants are in soil, stop feeding them nutrients and add a flushing agent to your water 7-10 days before you harvest. In hydroponics you can do this 4-7 days before harvest. Once the heavy metals and chemical salts are flushed, you're left with the essence of your plant at harvest. 

Flushing agents help clear your plant of these materials faster and more thoroughly than water alone. If you overfeed your plants and see signs of nutrient burn, use only water for the next two feeds and possibly use a flushing agent such as Clearex by Botanicare. The flushing agent helps restore the plant to homeostasis more quickly. Other popular flushing agents include Final Phase by Advanced Nutrients and FloraKleen by General Hydroponics.

Use the Best Water

Distilled or reverse osmosis (RO) water is best. The quality of the water you give your plants plays a big role in not only the overall quality of the plant but also in the quality of the soil or hydroponic system. 

Water from different sources contains different risks. City water often contains chlorine, chloramines and fluoride, plus the residue of a long journey through aging pipes. Well water may contain pesticide runoff, heavy metals, and above-normal levels of calcium, iron or other nutrients. These substances wreak havoc on soil microbiology, throw off your nutrient balance, and can be toxic to plants and people. Does unfiltered water work? It does, but know what's in it. The better the water, the better the plant.

Especially if you're using reverse osmosis or distilled water in coco or hydroponic systems, watch out for calcium/magnesium or Cal Mag deficiency. It's one of the most common nutrient deficiencies.

Avoid Overfeeding

Don't overfeed your plants. We've found that just about all nutrient companies recommend using too much of their product. Try starting young plants at a quarter strength of the label-recommended dose of nutrients, then slowly working up the amount as your plants mature. Watch out for signs of nutrient burn. In general, underfeeding plants is safer than overfeeding.

Different plants and strains respond differently to different nutrients. One nutrient company may be great for one plant while less effective on another. It's wise to search for testimonials from people using a specific nutrient on a specific plant and/or strain.

Monitor pH Levels

Knowing and adjusting pH levels is super important. When your pH is too high or too low, your plant won't absorb certain nutrients, even though you're feeding it the right stuff. Measure your pH after you add your nutrients into your reservoir or liquid solution, not before. (You'll need a pH tester or meter.) Stir your reservoir or liquid solution thoroughly and wait a couple of minutes before you measure the pH. Nutrients tend to bring your pH down because they are slightly acidic. For hydroponics, keep your pH at 5.5 to 6.5; for soil, 6.2 to 7.2.

• Base nutrients. These are the main course. They provide a wide range of elements that make up a more-or-less balanced diet. Most base nutrients are packaged in multiple parts or bottles, often with those bottles denoted for either the vegetative (growth) stage or blooming (flower) stage.


• Additives. Think of additives as your dietary supplements. Additives can be applied when your plant is showing deficiencies in a certain element, or if you're trying to arouse certain characteristics, such as taste, root growth or flower size.

If you're a beginner, Nutrient Starter Kits help. They include all the nutrients you need to grow two to four plants through their entire life cycle, from propagation to flowering and harvest.