I alternate between growing marijuana in soil, soilless mix or Grodan rockwool using organic, veganic or natural fertilizer or growing hydroponically using 100% synthetic or synthetic-natural feed programs.
For me, growing in soil is easier, but growing hydroponically is more efficient, controllable and predictable. And of course we’d all love an easy, reliable marijuana feed program in which we follow the manufacturer’s instructions and get the ideal parts per million and pH for our marijuana plants, as well as maximum absorbability of all nutrients elements. But it’s almost never like that, and here’s why:
- The majority of hydroponics nutrients aren’t tested on and made for cannabis plants. The manufacturers market their products in grow stores and some even show up at cannabis events, but when growers ask about their product testing and design, we discover their products are generic copies of tomato and corn fertilizers—they haven’t done any serious testing on cannabis and don’t know much if anything about growing marijuana.
- Cannabis has a unique suite of nutritional needs so it does best when given nutritional elements in types, ratios, and amounts timed for specific growth phases and targeted to increase production of buds loaded with THC, other cannabinoids, and terpenoids. Most nutrients manufacturers don’t understand those unique needs, so their products fail to maximize the genetic potential of your plants.
- Many fertilizer brands are inferior and lack quality control. They use cheap materials, and outsource their manufacturing. Nutrients concentration and pH buffering are defective; you get inconsistent root zone and nutrients solution chemistry that negatively affects your plants.
- Cannabis strains differ in their ability to handle nutrients. If you’ve ever grown multiple strains in the same garden using the same feed program, you notice some strains do well but others suffer. You sometimes have to create specialized feed programs for specific strains.
- The amount of nutrients your plants can handle are determined by many factors including the plant’s age and size, grow room temperature, humidity, vapor pressure deficit, water temperature, type of growing system, water quality and whether you’re adding C02 and using other cultivation acceleration strategies (such as professional LED grow lights). Problem is, the manufacturer’s dosing instructions are often generic, and their feed charts are confusing and inaccurate.
- Even though most nutrients manufacturers claim their products work equally well in soil, soilless mix, coco, rockwool, water culture, aeroponics and other grow systems, those systems aren’t totally equivalent when it comes to root zone nutrients absorption–a nutrients dosage, brand, or pH that works well in coco might not work well in rockwool, for example.
The good news is we’ve devised a nutrients evaluation program for ensuring your feed program is as safe and effective as possible. Let’s take a look at what supplies you need, and the steps you take…
- You need a high-quality pH and PPM (EC) meter, along with reliable pH Up and Down, and meter cleaning and calibration fluids. Most meter brands and models aren’t good enough for you. Please read this important article about meters.
- Clean and calibrate your pH/EC meters with reliable cleaning and calibration fluids at least once a week if not more frequently.
- Use reverse osmosis water. It’s almost impossible to get the full benefits of hydroponics growing if you’re using regular water that could contain chlorine, chloramine, contaminants, and a handful of nutrients elements (most often iron and calcium).
- Before you buy hydroponics nutrients, contact the manufacturer and ask them if they design and test their nutrients specifically for marijuana plants. If they say they do, ask for proof. Also ask for a specific dosing program for your early seedlings and clones, as well as grow phase and bloom phase. See if they have an integrated feed chart and dosing calculator that stacks base nutrients with supplemental products such as bloom boosters. An ethical, grower-centered nutrients company will have skilled growers providing product technical support. If they don’t, that nutrients brand isn’t good enough for you.
- Monitor your leaves before and after every feeding. The most important thing you’re looking at is the leaf tip at the point of the leaf. If the terminal 1/16th to 1/32nd of the tip is brown or yellow, but the rest of the leaf has uniform color, your feed program is ok. However if 1/8th inch or more of the leaf tip is brown or yellow and looks “burnt,” this is usually a sign of overfeeding.
- Beware of overfeeding. This is caused by making a batch of nutrients with too-high parts per million, but also happens when your plants are using more water than usual because they’re in a C02-enhanced, high-intensity grow light environment, or an environment with humidity below 50% and/or high temperatures. In those situations, plants take in and transpire more water, consuming more nutrients than they can handle. Fixes for this problem include dropping the parts per million by reducing mixing dosage, reducing amount of watering, changing environmental conditions that create extra water usage.
- Root zone materials such as soil, rockwool, coco coir and soilless mix can become saturated with nutrients elements that build up to harmful levels in the root zone. Obviously, this doesn’t happen in deep water culture or aeroponics. If you see significant leaf tip burn, do a mini-flush using reverse osmosis water and nothing else.
- Coco coir has unique chemical properties that often interfere with your feed program and harm plant performance, so be sure to get fertilizers made specifically for growing marijuana in coco coir.
- Before you decide that plant problems and leaf symptoms are caused by nutrients issues, make sure your grow room environment is in the ideal range, and if your plants are being attacked by pests or pathogens.
- Monitor your plants’ growth rate, leaf color and overall vigor and be open-minded about the causes of problems. We’ve seen situations in which plants weren’t growing as fast as they normally would, leaves were pale or too dark green, and stalks and stems were weak. The leaf tips weren’t burned, so the problem wasn’t necessarily overfeeding—it could have been underfeeding.
- An accurate diagnosis of underfeeding is difficult to achieve, given that overfeeding can lead to something called “nutrients lockout,” which blocks nutrients absorption and creates symptoms that look like underfeeding. Growers often mistakenly increase their nutrients dosage at this point, creating more overfeeding and more lockout. In this case, as with many nutrients problems in hydroponics, start with a mini-flush to purge the root zone of nutrients elements. Then carefully restart your feed program after talking to the nutrients manufacturer about your plant problems.
- In many cases, we’ve seen that changing your base nutrients brand can fix some if not all nutrients-related problems. Hydroponics base nutrients are the foundation of your feed program, and many base nutrients brands are made with inferior materials, formulas, and processes. If your grow room conditions are ideal, and you’ve checked pH, adjusted parts per million, done mini-flushes, and there’s no sign of pests or disease but you’re still seeing leaf symptoms or other problems, try a different base nutrients product.
When it comes to feeding marijuana plants, sometimes we get very lucky in our grow ops, sometimes we don’t. What I mean by lucky is when you feed your plants based solely on the hydroponic nutrients manufacturer’s dosage instructions and feed charts, and everything works well with no overfeeding, underfeeding or other nutrients-related problems.
Your plants are lush green and fast-growing in grow phase, go into pre-flowering as soon as you switch your lights to bloom phase, and you get big fat buds loaded with scent, taste, cannabinoids and terpenoids.
Now, you might be saying to yourself, “that’s not luck, that’s my skill.” So let me explain that when it comes to hydroponics nutrients and most other feed programs sold to marijuana growers, you’re lucky if you get easy-to-use nutrients products that work well consistently in all kinds of hydroponics systems and root zone media for several seasons and with all kinds of cannabis genetics.
Because in my experience and the experience of professional and home growers around the world, nutrients quality, reliability and performance are the weak links in our gardens. To put it bluntly, most fertilizer manufacturers who sell to marijuana growers are flying blind, using inferior materials and processing, haven’t tested their products on cannabis crops, offer confusing and inaccurate feed charts, and are far more interested in profits than in giving us scientifically-researched and proven products and technical support.
Just take a look at the many grower forums discussing crop failures with all the major nutrients brands including Canna, General Hydroponics, House & Garden, Biobizz, Botanicare and many others.
Yes, some marijuana growers get acceptable or even great results some of the time using some of those brands. But the unacceptably high percentage of growers frustrated by recurring nutrients problems in gardens where the grower is using reverse osmosis water, quality meters, an ideal grow op environment and savvy cultivation skills shows that nutrients are a big problem.
Inferior nutrients aren’t just a frustrating hassle that costs you time, money, bud potency and harvest weight–they’re also a ripoff. We have the right to expect that when we spend hundreds of dollars for nutrients that they’ll work flawlessly when used as directed, but in a shockingly high percentage of grow ops, that’s not what happens. And when you contact the nutrients manufacturer to ask for a refund or technical support, you often get evasion, incompetence, and even dishonesty.
The good news is that Growing Marijuana Perfectly is committed to investigating nutrients manufacturers with the goal of finding at least one that has a science-backed research and development program that tests their products on a variety of cannabis strains in all kinds of hydroponics, soil, soilless and outdoor grow systems, and is 100% dedicated to making flawless products that drive your marijuana plants to their highest genetic potential every crop cycle.
Just recently, we discovered a new nutrients company that might be the legit, reliable, honest manufacturer we’re looking for. After we’ve talked to them and tested their products, if we discover they’re making nutrients that work well all the time, you’ll be the first to know.
Just know this: the brand of nutrients you use makes a crucial difference in whether you’re happy or sad at the end of each marijuana crop cycle.