5 Rookie Mistakes for First-Time Hydro Growers

There are many challenges to transitioning from traditional soil gardening to indoor or hydroponic methods. Understanding some basic concepts can greatly improve the performance of your system and, in turn, the health of your plants. Here are some common mistakes to avoid.

Not Regulating Water Temperature

We’ve all seen potted plants thriving in hot outdoor conditions, so why would the temperature of your hydroponic nutrient solution matter? The main reason it’s important to keep your reservoir cool has to do with dissolved oxygen. As water temperature rises, the solubility of oxygen decreases. Even with the addition of air stones or hydrogen peroxide, the nutrient solution simply won’t be able to deliver adequate oxygen to your plants’ roots. This is especially important in deep water culture systems where roots are constantly suspended in water. Low water temperatures can also have negative effects on your garden. Hydroponic nutrients aren’t as soluble in cold water, and below a certain temperature many minerals will precipitate out of the solution where they are no longer available to your plants. Cold water can also lower the overall temperature of your plants, slowing metabolism. Chillers and reservoir heaters should be used to keep your solution between 55-70°F.

Using the Wrong Nutrients

There are more plant food products on the market today than could easily be counted, but most are not suitable for hydroponic use. Too often consumers buy products based on marketing or NPK numbers without considering the function of their system. Granular and organic products are designed to break down slowly, whereas mineral-based liquid fertilizers tend to be more readily available to the plant. Your local hydro store can help find the best solution for your system.

Paying too little attention to pH…or too much

Free image/jpeg, Resolution: 992×1023, File size: 96Kb, nutrients and ph for plants growth, diagram

Each essential plant nutrient is absorbed by the roots within a specific pH range. The majority of minerals such as nitrogen and calcium are absorbed well at a neutral pH of 7.0. Other important nutrients like iron are better absorbed at a lower pH. Soil provides some buffer against pH lockout, but it’s important to keep a hydroponic system within an appropriate range so that every essential nutrient is available to the plant. For most scenarios this range will fall between 5.5 and 6.5. Over time, various factors will cause the pH of the nutrient solution to drift. When the pH moves outside the appropriate range, a concentrated acid or base can be added to correct the imbalance. While it’s important to keep the solution within the right range, don’t focus too much on any particular number; overuse of pH adjusters will alter the chemistry of your system, leading to more problems.

Relying on Trendy Passive Hydroponic Methods

Many people looking for the simplest way to try hydroponics will turn to passive methods such as the growing style developed by University of Hawaii researcher, Bernard Kratky. In the Kratky method, plants are suspended above a reservoir of nutrient solution without the use of circulating pumps or air stones. While this is a great low-maintenance approach for students and hobby growers, it lacks one of the main benefits of growing hydroponically, which is ability to boost oxygen at the root zone. Plants take in oxygen through their stomata as well as their roots, and keeping your nutrient solution oxygenated will also prevent the growth of harmful pathogens. The performance of your hydroponic system can be greatly enhanced with the addition of a single air stone or small circulating pump.

Ignoring Soilless Media

One way to get the performance of hydroponics with the ease of soil gardening is through the use of a soilless grow medium such as coconut coir. These substrates can be used alone or combined with aeration materials like perlite to create soil-like blends. Use it in normal plastic or fabric nursery pots and water with a hydroponic nutrient solution (by hand or drip irrigation). This method provides a buffer against pH and moisture fluctuations, and you won’t have to worry about a small mechanical failure killing your plants. At Garden Grove Organics, we’ve spent years developing our very own custom soilless medium, Easy pH Mix. A favorite of our customers, the Easy pH Mix combines incredible pH stability along with great aeration and drainage properties. Find it here.

How to Deal with a Spider Mite Infestation

Spider mites are one of the most common pests encountered in indoor and outdoor gardens. If left untreated a spider mite infestation can wreak havoc on your plants, putting a serious dent in your yield and quality. We’ll discuss identification and look at a few ways to get rid of these bad bugs as well as some preventative measures you can take.

It’s important to positively identify any problem in your garden before attempting a solution. As their name implies, spider mites are not insects but part of the arachnid family. They tend to hang out on the bottom sides of leaves, and although they are small they can be seen with the naked eye if you know what to look for. Affected leaves will show small yellow spots where mites have sucked out material from plant cells. Heavy webbing on buds or flowers indicates an advanced infestation that may be a threat to the survival of the plant.

Before going after the mites directly it’s a good idea to eliminate the areas where they thrive. Larvae hatch from eggs then go through two nymph stages before reaching adulthood in as little as five days. At each stage the mites must shed their exoskeletons. This molting process occurs most easily in dry conditions such as dead plant material. Remove any dead or severely damaged leaves from your plants then clear the area of any loose plant matter. Get rid of old bags of dead leaves since these can be a breeding ground for pests. Keep your plants well-watered.

Spider mites are low on the food chain, so you probably won’t see out of control infestations outside. Indoors, mites have few predators, so unchecked populations can grow exponentially. One option is to introduce predatory insects into your indoor garden. Ladybugs are a good all-around and easy to source beneficial bug, and there are predatory mite species that can be even more effective. If you choose this route, make sure any sprays you use are compatible with your beneficial insects.

If all else fails, there’s always the chemical route. But don’t fret: There are numerous safe and effective mite control products on the market that are suitable for ingestible crops, and many even carry organic certifications. Some of the most effective of these are made using essential oils from plants like rosemary and cinnamon. Try these gentler options before resorting to neem oil or pyrethrins. For most effective use, apply sprays at 5-7 day intervals and alternate active ingredients every 2 applications.

Don’t rest when you stop seeing damage. Spider mites are good at hiding and they lay lots of eggs. If you’re not careful you could have a second wave of mites which are now more resistant to the sprays you used before. Keep fighting using every tool available until you are beyond certain that every last mite and egg has been eliminated, then spray down floors and walls with a mild bleach solution. With some consistent practices and determination spider mites can be easily controlled and sometimes even eliminated completely.

Super Soils

With the recent passing of legendary California breeder Subcool, I decided to do a post about super soil, or more specifically, Subcool’s Super Soil. The term “super soil” refers to an organic soil/fertilizer blend that is designed to nourish the plant from start to finish without adding anything but clean water. There are a few commercial super soils on the market, but most growers follow a recipe, and over the years the Subcool recipe has become the gold standard in water-only blends.

Super soils produce intensely flavored flowers without all the maintenance of a hydroponic system. But don’t expect high yields; this method of growing was originally designed for medical patients who didn’t have the ability to work in a garden all day, and who didn’t need an excessively large stash. It’s also a great method for first-time growers, especially those transitioning from traditional outdoor gardening techniques.

One step that cannot be skipped is the cooking process. The raw organic fertilizers in this recipe will burn clones or small seedlings if the soil microbes don’t have adequate time to break them down. We’ll dive deeper into this topic a little later on.

The Recipe

  • 8 large bags of a high-quality organic potting soil with coco fiber and mycorrhizae (i.e., your base soil)
  • 25 to 50 lbs of organic worm castings
  • 5 lbs steamed bone meal
  • 5 lbs Bloom bat guano
  • 5 lbs blood meal
  • 3 lbs rock phosphate
  • ¾ cup Epsom salts
  • ½ cup sweet lime (dolomite)
  • ½ cup azomite (trace elements)
  • 2 tbsp powdered humic acid

Here’s the basic recipe, straight from the horse’s mouth, published in High Times back in 2009. This list is enough to fill two large trash cans with super soil concentrate, which will then be “cooked” outside for 30-90 days and combined with base soil for the final planting. Use these ratios as a starting point and adjust the amounts for the total volume of super soil you need. Also keep in mind that Subcool was always tweaking his signature recipe, so this is simply a snapshot of what he was doing at the time.

Base Soil

A good base soil is just as important as the amendments you add to it. Aeration and water retention are key since this is a hands-off method, so choose a mix that is airy with plenty of perlite. Peat moss is the main ingredient in most commercially-available potting soils, but I would recommend using a product that has at least 20% coconut coir. While peat tends to be acidic, coco coir is pH neutral. Coco coir also has a lower cation exchange capacity than peat, meaning it’s less likely to hang on to plant-available nutrients.

Subcool recommends Roots Organics Original Potting Soil, which is a great choice. Another soil brand we’ve grown to love is Royal Gold. They offer coco-based soilless media with varying levels of organic amendments already present. Choose Tupur for a lighter blend or Mendo Mix if you want something that’s a little more fortified straight out of the bag.

Earthworm Castings

Earthworm castings (poo) are a smorgasbord of beneficial goodies for your plants. Along with adding aeration and structure to soil, they contain an array of micronutrients and trace minerals like iron and calcium, among many others. Most importantly, worm castings are an incredible source of plant-beneficial microbes. Studies from top universities have shown improvements in seed germination, rooting, and flower production, along with a reduction in disease and wilt in plants amended with earthworm castings.

Wiggle Worm is a tried and true source of quality worm castings, and it’s readily available in 15 and 30lb bags. You might also be able to find a good source of local worm castings depending where you live.

Steamed Bone Meal

Granular bone meal contains a phosphorus to nitrogen ratio of about 5:1, so it’s great for balancing out phosphorus levels in organic mixes that tend to be high in nitrogen. It also contains some calcium and trace minerals. Fish bone meal is nearly identical to classic steamed bone meal in terms of the nutrients it can provide, but it smells worse and generally breaks down faster. Since a super soil needs to last around 10 weeks we recommend using a product like Down To Earth Bone Meal.

Bat Guano

When this recipe refers to “bloom” bat guano, it means a guano high in phosphorus, as opposed to more commonly available forms which are higher in nitrogen. Guanos have many of the same plant benefits as earthworm castings such as improved soil structure and the addition of trace minerals and microbes. One downside to guano is the environmental harm caused by its production. Many developing countries use bat guano as a source of income, bulldozing caves and damaging or permanently destroying bat habitats in the process. If you’re set on using a guano, we prefer Peruvian Seabird Guano, which is harvested using more sustainable practices.

Blood Meal

Like bone meal, blood meal is a byproduct of the meat industry. Blood meal is another readily available source of organic nitrogen, and its acidity helps buffer the soil against pH shifts. An added benefit of blood meal comes in the deterrence of certain garden pests. Small mammals like rabbits, squirrels, and raccoons will associate the smell of dried blood with the presence of a predator. Keep in mind that larger animals like deer won’t be so easily fooled.

Rock Phosphate

Rock phosphate, sometimes called rock dust, is exactly what it sounds like: a mined mineral containing high levels of phosphorus and trace minerals. Like many of the inputs on this list, rock phosphate can help improve soil structure and aeration. It can also prevent some types of insect larvae from burrowing into the soil. Since rock phosphate is a mined clay, the exact consistency and nutrient ratios will depend on the source. Down to Earth Rock Phosphate is a great cost-effective version we always keep in stock.

Epsom Salt

You’re probably used to seeing epsom salt in the personal care aisle of the pharmacy. Chemically known as magnesium sulfate, epsom salt is a simple ionic compound made of magnesium, sulfur, and oxygen, all of which are essential to your plant’s overall health. Unlike organic compounds, ionic compounds like magnesium sulfate are immediately plant-available. Epsom salt also dissolves easily and makes a great addition to a foliar spray. While epsom salt is easy to find in many forms, we prefer the high purity and fine grain size of Monterey Epsom Salts.


Lime is made from pulverized limestone and has been a popular agricultural amendment for centuries. The high pH of lime makes it another great soil buffer, and it can help to balance out low pH inputs like peat and blood meal. Dolomitic lime, sometimes known as sweet lime, contains the mineral dolomite which is comprised of calcium and magnesium. It can also contain other important elements like iron, manganese, zinc, and cobalt. 


Azomite is a mined mineral which comes from a single source, an ancient volcanic ash deposit in the Utah desert. While it can technically be defined as a silica ore, Azomite’s complex mineralized structure contains a wide array of plant-available elements. The name “Azomite” actually stands for “A to Z Of Minerals Including Trace Elements”. Since there’s only one source of Azomite, it’s hard to go wrong.

Humic Acid

The final item on the list might just be the most complex and least understood ingredient in this recipe. Humic acids are the end result of the breakdown of organic matter over millions of years, forming complex carbon-based molecules. They enhance the soil physically by improving water retention and soil tilth, and by preventing surface cracking. Humic acids also enhance the soil chemically by buffering pH and chelating minerals and metal ions, allowing them to be more easily taken up by plant roots. Entire books have been written about the roles of humic and fulvic acids in soil biology, and we may focus more on them in a future post.

The Mix

Now that you have a basic idea of what each ingredient does let’s talk about mixing it together. The obvious and most basic method would be to simply pour everything into a large bin or kiddie pool and mix it up. Although that’s an effective enough way to go, the labor can be back-breaking, especially if you are doing a large batch for outdoor plants.

One less labor-intensive method involves a large tarp and, ideally, two people. Open the tarp up and spread it out over a large, flat surface. Pour around 25% of your base soil onto the center of the tarp. Pour your first amendment in a circle around the edge of the base soil you just poured. Grab any corner of the tarp and fold it over toward its opposite corner, then fold it back out flat. Repeat this process at each corner, folding the mixture over on itself each time. Add the next amendment and a little more base soil, and continue folding. 

Whichever mixing method you choose, make sure everything is evenly blended before moving on to the next step.

The Cook

Pour everything into large trash cans. This particular recipe should fit nicely into two 44 gallon Brute trash cans or equivalent containers. The mixture should be moist, but not soppy wet. Add 2-3 gallons of water to each trash can if it seems too dry. The goal is to have a homogenous blend of soil, water, and organic inputs that the microbes can break down into plant available nutrients. Place the trash cans in a warm area for at least 30 days. If cooking the mix outside make sure to place the cans where they can get maximum sunlight. In cooler months you might have to cook the mix for up to 90 days to get everything to break down. 

Once your concentrated organic mixture has finished cooking you’ll need to mix it with more base soil before transplanting, otherwise you run the risk of burning young seedlings or clones. The most basic method would be to cut the cooked concentrate 1:1 with more base soil and transplant into containers as usual. Subcool’s instructions were to fill the bottom half of each container with concentrate and the top half with base soil; this way the plant has more time to get established before the roots reach the heavily fertilized layer. Either method will work, but we consider the 1:1 mix to be easier and less risky.

[Do not skip the cooking step. Rapidly dissolving organic fertilizer can contain high concentrations of harmful chemicals like ammonia, and microbial activity can spike soil temperatures to over 130 °F.]

Final Thoughts

While super soil methods can yield some really fantastic results, they can be a roll of the dice. If you stay 100% true to the method you won’t have many options for correcting any deficiencies that may arise. Using a larger pot will help provide a buffer against swings in pH and nutrient deficiencies, and drought; if you normally use a #5 container try upsizing to a #7 or #10.


Harvesting 101

[NOTE: This article is presented in its original unedited version; however, in the years since its first publication there have been studies conducted which call into question the effects of "rinsing" or "flusing" techniques on the quality of the final product.]

When To Chop

When is a crop ready for harvest? That question can only be answered through experience and deep observation. Start your research by checking websites for similar plants, and consult other growers who have worked with the same cultivar. Temperatures, nutrients, and plant health can all effect the harvest schedule, so timing may vary by a few days from one harvest to the next.

Once you have worked with the same strain for three or more harvests, you will be able to recognize color and fragrances that indicate ripeness. Even plants that stay green through harvest will change color slightly. Green Zebra tomatoes start out green and are harvested after that have matured to a slightly different green. Growers familiar with this strain can see the change from green to bright green, because experience has been their teacher. Use a loupe or microscope to view subtle changes in color. Harvest one third of your garden, while the rest grows for three more days. Harvest another third, and let the last few plants grow for another three days. Now you have three different harvest times to compare, so you can know when to harvest the next crop.


Stop feeding your plants for one to two weeks before harvest. Keep watering, but omit the nutrients. Plants store fertilizers before converting them into biomass. If you keep feeding in the days before harvest, the stored fertilizers will still be in the plant when you consume it. This will drastically reduce quality. Highly inoculated, low NPK compost tea is a great addition to the rinse cycle. Use a tea with high levels of beneficial microorganisms, but minuscule levels of nutrients (example: NPK 0.03 - 0.03 - 0.03). Beneficial bacteria and fungi will break down nutrients in the root zone so leftover plant food can be rinsed away.

Chelating agents put a non-stick coating on fertilizer salts. When chelates are used in the rinse week, salts become loosey-goosey instead of stuck to roots or soil. Those salts can now be rinsed away with water. Ask your local hydro shop for their best rinsing agent. These chelate blends are tailor-made for removing unwanted salts from your garden. Filtered water should be used over chlorine-rich tap water. Chlorine can diminish yield and quality.

Use these products in succession for the best possible result. On day one of your rinse cycle, give your garden twice the normal amount of water combined with compost tea. On day two, give them water. Begin using the rinsing supplement (chelate blend) on the third day. This step should be done with at least twice the required amount of water, for encapsulation and removal of unwanted elements. After introducing the chelates, simply rinse the growing medium with filtered water for the next five or more days. Each time you water, use the same amount as your containers. For instance, a garden with ten five-gallon buckets requires 50 gallons of water each day. For hydro systems, simply empty the reservoir and refill it with water daily. This rinse plan will give you the cleanest tasting harvest you have ever experienced!


Many culinary gardeners enjoy dried herbs. For the best possible taste, these herbs must be thoroughly dried. You may think your sage is dry after three days, but the stems are holding moisture that your fingers cannot detect. Let it dry another three to four days before storing it in a clean mason jar. Air, light, and bacteria are the enemies of dried herbs. Seal your herbs in glass jars with airtight lids, and keep them tucked away. Bacterial damage is the result of moisture, and it smells terrible! Thoroughly dry the plant matter and periodically check stored herbs for dampness.


Often the best flavor and potency is achieved after a harvest has been on the shelf for a few weeks or months. Some growers will consume a harvest before it can achieve the complex aromas and flavors that come with age. Try to store some samples for two months, six months, and nine months. With experimentation you can isolate the ideal age for your particular variety of herbs.

Do LEDs work?

One of the most common questions we get here at Garden Grove Organics is how light emitting diodes really stack up to traditional light sources like high pressure sodium or metal halide lamps. There are so many brands of horticultural LED fixtures available now that many customers just want to know which model is right for them.

Right now you might be saying, “I’ve tried LED and wasn’t happy with the yield.” The truth is all LEDs are not created equal, and there are many false claims made by manufacturers. We hope this guide will help clarify some of common misconceptions surrounding modern LED technology.

Cliff Notes / TLDR: If you don’t have time to read the whole article, the short version is that we love LEDs for all stages of plant growth. You can can find a carefully curated selection of high quality LED lighting here.


LEDs have taken over virtually every lighting market on the planet as the result of their high efficiency and long life compared to traditional lighting like HID lamps and fluorescent tubes. While those older technologies are capable of producing 50 to 100 lumens per watt, the best LEDs can produce over 200 lumens per watt. That allows homes and offices that switch to LED to save 75% or more in lighting costs.

While lumens measure the intensity of light as seen by humans, plants sense light differently, so they need their own unit. Micromoles (µmol) are the general unit of measure for photosynthetic light, the light plants are able to use. It is expressed in µmol/sec (the amount light produced from a source) or µmol/m2/sec (the total light hitting a given area). This might sound a little complicated, and it can be, but with a little basic understanding you’ll be in a much better position to navigate the vast sea of LED marketing.

Now that we’re speaking in terms a plant can understand, let’s see how some of the most common technologies compare:

The chart above shows typical power usage and light output statistics for some of the most common horticultural lighting technologies. You can see that a high performance LED uses less power and provides more light output than the best traditional lights available. You might also notice that many cheaper LED fixtures, what we call pizza box lights, are actually less efficient than CMH and DE HPS.

One thing to note is that these numbers are based on the efficiency of the complete fixture. Some manufacturers will boast the on-paper efficiency of their lamps or diodes, but the real world numbers are usually less impressive.


Choosing the right spectrum when it comes to plant lighting is important for several reasons. First, the overall spectrum of light directly determines the shape and growth characteristics of the plant, known as morphology. This spectrum-dependent relationship is called photomorphogenesis, and it is completely independent of photosynthesis, the process plants use to harvest energy from light.

One example of this phenomenon is the shade avoidance response. As a general rule, the red end of the visible light spectrum penetrates deeper into the plant canopy than the blue end of the spectrum. When plants receive a high ratio of far red (730nm) they sense that they are being shaded by taller plants. In response, they stretch out and elongate their stems and leaves, a process called etiolation. The resulting growth is typically weaker and less desirable. For this reason, we don’t recommend LEDs that incorporate added far red.

Another feature touted by many LED manufacturers is the addition of ultraviolet, or UV light. While UV light can have some interesting effects on oil production and color, the benefits are not consistent across the board, and UV-LED technology has a long way to go. For those who like to experiment, we recommend and sell specially tuned fluorescent tubes which emit high levels of UVA and UVB. Contact us for details.

Full-spectrum diodes use a special phosphor coating to produce a wide range of colors from a single component. This type of light appears white or yellow to the human eye, similar to the color of the sun. We prefer 4000K full spectrum LEDs for all stages of plant growth. This spectrum provides a balance of all visible colors for sturdy, compact growth, and it’s much easier to work under than purple LEDs and even HPS.

COBs and Strips and Quantum Boards, OH MY!

We’ve seen that LEDs can provide higher efficiency and a fuller spectrum of light compared to traditional technologies, but what about all the different flavors of LED out there? While the vast varieties can seem overwhelming, all LEDs are simple semiconductors that emit photons (light) when current passes through them.

Dual Inline Package (DIP) – These are the classic “clown nose” LEDs that have been commonplace since the 1980’s. They are often found in “pizza box” LED grow lights in 3- and 5-watt versions using computer fans to cool them. This older technology is cheap to produce, but the performance and life ratings aren’t well suited to the demands of horticultural lighting. Early products using DIP technology yielded poor results, and were responsible for giving LED grow lights a bad reputation.

Chip On Board (COB) – In chip on board technology semiconductors are mounted directly to a circuit board. This allows many individual low power diodes to be placed close together in a single package. The resulting component looks and acts like one big, bright diode. However, there are drawbacks to packing everything so closely. Heat is the enemy of light emitting diodes, and it can reduce efficiency and shorten lifespan if not removed properly. Some manufacturers use heat sinks and fans to remove heat, but those add to the cost, weight, and energy usage of the fixture.

Quantum Boards – Quantum boards are simply circuit boards densely populated with surface mounted LEDs (SMDs). These SMD-style diodes are some of the most efficient light sources available, capable of efficiencies well over 3 µmol/joule. Mounting these highly efficient diodes on metal-core circuit boards allows heat to be dissipated into the air naturally, eliminating the need for fans or heat sinks. In addition, the even spread of light sources provides extremely uniform photon delivery at the plant canopy. Some great examples of LED grow lights using quantum board technology include the NextLight Mega and HLG 550 V2 R-Spec.

LED Strips – LED strips or bars are like quantum boards, but arranged in long rows instead of squares or grids. These lights are similarly capable of ultra high efficiency and long life ratings, without the need for additional heat sinks or fans. What sets strip or bar lights apart from those using quantum boards is the pattern of light output. Strips of diodes placed at even intervals provide extremely even coverage at close range. That makes this type of grow light ideally suited to growing shorter plants in vertical racks. A great example is the Gavita 1700e, which can be found in vertical commercial grows around the world.

NFT Harvest 1

Thanks for checking out the first video in our new series NFT hydroponic growing series. We plan to do a lot more videos soon including seed starting and spring planting with NFT sytems, along with some more interesting topics like growing carrots hydroponically indoors. So check back often for more tutorials and reviews.

Don’t hesitate to reach out if you have any questions or comments about the video, running NFT systems, or if you would like to buy any of the equipment you’ve seen featured. We carry all the stuff you need for a successful indoor or outdoor garden at our store in Covington, KY, so stop on by or give us a call.