I constantly hear from my cannabis grower community about their trials and tribulations when it comes to problem products, and so I want to share these issues to help the rest of us best avoid our own grow op failures.
Many growers use inferior hydroponic nutrients, the result being diminished yield and potency. Inferior nutrients in pure hydroponic systems such as deep water culture, rockwool or aeroponics can quickly damage if not completely ruin a cannabis crop.
When nutrients aren’t made by professional cannabis growers with cannabis growers in mind, they’ll likely be defective because they’re not tested on and designed for cannabis plants. Crops will grow and yield if you’re using generic nutrients, but not anywhere near as well as if you use a feed program designed specifically for cannabis.
Often is the case that hydroponic nutrient defects go beyond the generic. This includes products that are chemically unstable, have inadequate pH buffers and chelates, and contaminate your crops with dangerous heavy metals.
As an example, the grow-phase version of General Hydroponics FloraNova has a whacky N-P-K ratio that deprives plants of sufficient nitrogen, but that’s not the only problem. The bigger problem is it’s a one-part fertilizer — and you simply can’t cram all essential nutrient elements together in one bottle and expect them to remain chemically balanced in solution.
Two- and three-part hydroponic base nutrients are far more prevalent in the marketplace because they ensure element stability by separating specific nutrient elements into different bottles, so that they aren’t stored together on the shelf. Rather, these ingredients are only combined when the grower mixes them into the nutrient reservoir.
Another brand on the market, Heavy 16, has been known to give growers buds with an unpleasant chemical taste, and won’t burn clean to produce white ash, no matter how much you flush your plants. Growers who use Heavy 16 base nutrients in deep water culture or aeroponic grow systems have also reported chronic problems keeping pH in range, complaining that Heavy 16’s Prime and Fire bloom booster products also cause burned roots.
What’s In That Soil?
For a long time, cannabis growers have been buying problematic soil products sold in hydroponic stores. These soils have inconsistent batch control with respect to ingredients, fertilizer load, aeration, perlite, pH buffers and pests. This will likely have a negative impact on root growth, nutrient uptake and overall plant health.
If you should find the soil in your grow room infested with root aphids, spider mites, thrips or mealybugs, and you have very tight vector control that would block these pests from entering your space on external clones or via air flow, then they likely came in with your soil.
An additional problem frequently seen with commercial soil is that it can come with an on-board nutrient charge of dubious strength and quality. Growers tend to stop using soil in favor of soilless mix or pure hydroponic growing because soil is flat out unpredictable, and the on-board fertilizer charge of most commercial soil is part of the reason for that unpredictability.
Whether it’s super soil or commercial soil brands such as FoxFarm, you simply don’t know what you’re getting. And sometimes, the manufacturers don’t know, either. Cannabis growers start their seeds or clones in soil, wondering how many days and weeks before they need to use fertilizer. As a consequence of this lack of certainty, they lose control of their feed program, which leads to inferior crop outcomes.
In some cases, commercial soil has a built-in, non-optimal nutrient charge, plus the wrong soil pH buffering. Either of these two factors alone can cause problems, but together they create a time-consuming, crop-harming situation in which the grower endlessly chases the pH and nutrient load, trying to clear and balance the soil so the plants can be successfully fed.
Inconsistent batch control, as mentioned, is also a big problem. If buying commercial soil, I recommend asking the hydro retailer to show you the contents of one bag from a shipment to examine it for pests and see how clean it is. Always hold the seller accountable. If you buy soil and find that it’s full of sticks, garbage and pests, bring it back and demand a refund.
One of the worst mistakes a grower can make is to buy Scotts Miracle-Gro soil, which tends to be filled with pests, has poor aeration, bad pH buffers, and a mysterious 3–7-month time-release fertilizer charge that isn’t explained in detail on the packaging. The fertilizer-charge ratios and percentages aren’t designed for cannabis and can make a mess of your plants with too much nitrogen, as well as nutrient lockout.
So, how do you find good, clean soil? Take it from me, the cleanest, kindest, most reliable soil I’ve ever used is Potter’s Gold.
The Importance Of Accurate pH Meters
If you’re a soil cannabis grower, a pH meter is an absolutely necessity. Finding reliable pH base nutrients and parts-per-million meters has become difficult in the past five years. Even the usually reliable Bluelab Combo Meters have been problematic, because resellers have been shipping the pH probes when they’re dried out and already defective.
There have also been similar problems reported with Hanna meters sold through third-party vendors. However, please note that overall, Hanna and Bluelab meters (which cost about $165) are reliable tools for measuring soil pH.
Lower-priced pH meters that cost less than $75 are mostly useless. If they work at all, they probably won’t work for long. You’ll also find that lower-priced pH calibration, probe storage and pH adjustment fluids are defective and can destroy probes, while also giving you inaccurate calibration.
Remember, if your nutrient pH is wrong, then your plants may starve to death.
After a lot of heartbreak due to faulty pH meters, I spent more money on a meter I could count on and have advised my grower network to do the same. I purchased incredible meters from Apera Instruments and Sper Scientific that cost upward of $310, but ultimately gave me unparalleled accuracy, performance, longevity and reliability. Worth it.
Apera and Sper are professional meter manufacturers and you’ll be fascinated by the many different varieties of metering you can do with their gear. Growers running deep water culture and aeroponic systems will be especially interested in the range of dissolved oxygen meters.
Sper doesn’t just specialize in pH meters. Growers who want to see what police see when using high-tech sensors to locate your hidden grow op can get their hands on a Sper Thermal Imaging Camera. If you use this camera outside your grow house and detect intense heat loads within, you know it’s time to install infrared blocking insulation.
As with any other industry, the hydroponic nutrients and gardening supplies industries have some exceptionally good manufacturers and products, some mediocre ones, and some terrible ones.
Visit or call hydroponic stores you trust, and ask staff what products work well and why, and what products to avoid. However, be aware that some hydroponic stores may not be giving you accurate information, because they’re given financial incentives from certain manufacturers to push specific products, even if those products are inferior.
If you’re networked to a community of cannabis cultivators, talk to them about hydroponic products and commercial soil they’ve had grow success with.
Take daily notes about your grow op, analyzing to detect what role, if any, your equipment and nutrients are playing in your crop’s performance.
And always remember to avoid unethical manufacturers like Scotts Miracle-Gro, General Hydroponics and Botanicare, and use only the best hydroponic nutrients, pH meters, technology and inputs to enjoy your biggest, most potent yields yet.