by Nebula Haze
The current (undeserved, in my opinion) legal status of marijuana makes it so that many new growers end up learning some hard lessons on their own.
I regularly see pictures of plants that are struggling with caretakers that don’t know what’s wrong. Often, pictures immediately show that the owner is missing a vital piece of plant care knowledge that would totally solve their problem.
Avoiding problems is how you grow amazing weed!
With this in mind, we’ve compiled a short list of the most common mistakes we see new growers make. Read below to find out if you’re making one of these common blunders!
1. Not Managing pH
When you start cultivating cannabis for the first time, there are a lot of acronyms, formulas, and regimens it seems you need to remember. After hearing PPM, NPK, pH, Lucas Formula, 18/6, 24/0, etc., most people want to ignore the jargon and try just watering a plant.
The jargon can definitely be overwhelming, and I would agree that a lot of it can actually be ignored… except pH.
Even though this plant has access to nutrients in the soil, the leaves are showing nutrient deficiencies due to receiving low-pH water. Bad root pH can cause all sorts of leaf discoloration, problems, and deficiencies! The problem cleared up as soon as the plant started getting water with a neutral pH.
Managing pH is one of the more technical details that pretty much ALL growers have to deal with unless you’re lucky enough to have perfect water.
Even in an organic super soil setup where pH matters less and many growers say pH doesn’t matter at all, you’ll still get nutrient deficiencies if the pH is totally out of whack. In fact, the picture above shows a super soil plant. Bad pH makes for sickly leaves, plants that struggle to make big buds, and overall poor cannabis growth.
Soil growers aim for 6-7 pH for best nutrient absorption
Growers in hydro, coco, and other soilless media aim for 5.5-6.5 pH
How to Avoid:
To your plant, root pH determines which nutrients can be absorbed. When the pH is in the wrong range, a plant can’t uptake nutrients properly.
Why? PH affects the bioavailability of nutrients to the roots because each nutrient molecule takes on a different chemical form depending on the local pH. Some forms are easily absorbed by the roots, while other forms are difficult for your roots to uptake. When your plant can’t absorb nutrients due to pH, you’ll see nutrient deficiencies even if the nutrients are physically there.
Get yourself a pH Testing kit and make sure you’re feeding your plants with water in the correct range:
Hydroponics: 5.5 – 6.5 pH (including coco and other soilless media)
Soil: 6.0 – 7.0
In my experience, most nutrient deficiencies are actually pH problems. Remember this and you’ll keep your plants looking beautiful.
2. Using Too Much Nutrients
This is a mistake that’s very easy to make, and the majority of growers will do this at some point. Myself included!
Here’s a large part of the problem: Most nutrient companies include a feeding schedule with their nutrient systems, and most of the feeding schedules recommend nutrient dosages that are way too high.
Overfeeding leads to a well-known affliction called nutrient burn (commonly referred to as “nute burn”). Nutrient burn won’t kill your plants in most cases, but they will leave an eye-catching reminder of their presence for the remainder of the grow.
Brown leaf tips all over the plant is a sign of nutrient burn, which is caused by too high levels of nutrients
Note: If you’re seeing yellow tips on only the top leaves, it may be light stress. If you’re seeing yellow or brown around the outside of the leaves (not just the tips) you may actually be seeing a copper deficiency or potassium deficiency. I’ve also occasionally seen a plant get discolored tips from overwatering, so that may be something to consider if plants seem droopy and you feel like you’ve been watering a lot.
How to Avoid:
Use the same feeding schedule that comes with your nutrient system, but only use one half (1/2) of the recommended dosage to start.
Example: If the feeding schedule calls for 2 tsp of nutrient solution per gallon of water, use only 1 tsp at first.
You should raise the nutrient levels if your plant starts getting pale or lime green all over, because that’s the main sign it needs more nutrients overall. For example, slowly move up to 3/4 strength or more as needed. Unless I’m growing with really strong lights or heavy feeding plants, I rarely need to give my plants nutrients at more than half (1/2) strength.
3. Overwatering (watering too often or too much at a time)
Many of us were brought up thinking that plants need sunshine and water every day. This, combined with a new grower’s thirst to provide for their plants, causes many people to water their plants more than is needed.
Overwatering prevents plant roots from getting enough oxygen, which causes plants to adopt a droopy posture. Overwatering can even kill plants in severe cases. Luckily, overwatered plants can almost always be restored to full former glory with proper watering practices.
How to Avoid:
Overwatering comes from watering too frequently or giving too much water at a time. Here’s how to water properly:
- Soil – Water plants when the soil feels dry up to your first knuckle (or if the pot feels light).
- Coco Coir – Aim to water plants every 1-2 days. If coco is staying wet for 3+ days, try giving less water at a time until plants get bigger and start drinking more. Don’t wait for your coco coir to dry out, but don’t water if the top inch feels “wet”. If the container feels light, it’s definitely time to water!
- Seedlings – Learn how to avoid overwatering seedlings (very common!)
For DWC/Water Based Hydro, make sure you have large airstones that make lots of bubbles. Since overwatering is essentially oxygen deprivation to the plant, you can actually overwater your hydroponic plant (in a sense) by not providing enough oxygen.
4. Bad Starting Genes
Oh, how tempting it is to grow a bagseed (a seed you find in your buds). You like the buds it came from, and it’s free. What’s the problem?
Many growers have been pulled in by the prospect of a growing a free seed found in their marijuana, and many of these growers have been disappointed. That’s because seeds you find may be duds, males, runts, or hermaphrodites. What’s worse, when the seeds do grow well, the buds are often nothing like the ones you found them in. That’s because the traits you want have not been stabilized into a strain.
How to Avoid:
Get good seeds from a reputable source. If you’re going to spend money on good lights and nutrients, you’re wasting that potential on a plant with inferior genes or the wrong sex.
There are many trustworthy sources of seeds. I’ve been using Seedsman for over 10 years, though recently I’ve been really pleased with The Vault (due to the great prices), and MSNL (due to the great customer service and unique genetics). In any case, it’s a good idea to go with a company that will reimburse you in case your seeds don’t arrive or are duds.
Growers who start with clones should exercise even more caution because clones are a common way to get bugs. My main suggestion is to know the person who is selling/giving you the clones and, if possible, inspect the clones thoroughly. Even better, quarantine the clones for a week or two while watching for signs of pests. Diseases/pests like spidermites or thrips can easily spread from clones to your entire garden.
5. Not Enough Light
I’ve come across quite a few pictures sent in where a grower has a plant sitting under a single incandescent bulb, or a reading light, or even on a window sill while it’s clearly snowing outside.
Give more light if your plant is growing tall/stretchy with a lot of space between nodes
Although younger plants can grow okay without much light, plants will not grow big buds in the flowering stage without intense light levels.
Buds stay small and airy if a plant doesn’t get enough light in the flowering stage
How to Avoid:
The amount of light given to your plant has an enormous impact on growth rates, bud density, and yields. Plants need light to grow, and plants need intense light to make big buds. You can expect the amount of bud produced to be somewhat proportional to the light intensity.
But that doesn’t mean you need to go out and buy a huge hot grow light for your garden. These days there are small intense LEDs and incredibly efficient mid-size LEDs that deliver high light levels without a ton of heat or electricity.
6. Ignoring Privacy
Even in places where weed is legal to grow, it’s a good idea to keep your garden relatively private. There’s usually no benefit to advertising you are growing cannabis plants and it can sometimes cause problems. Nosy neighbors may give you a hard time, or thieves may learn of your garden and try to steal your plants because they know you’re unlikely to call the police.
Here’s a short list of things I’ve seen in pictures or read in emails:
- Weed in windows sills with a clear view to neighbors and passing traffic
- Uploading pictures of cannabis plants with identifying information (such as mail with name and address visible)
- Growing weed in a low-fenced backyard adjacent to other houses
- Not bothering to filter cannabis odors even though you know the smell bothers people who live near/with you
Don’t do this in open view. It’s common for thieves to steal plants right as they approach harvest!
Or this. The smell from these plants overwhelmed the entire neighborhood. Try to be a considerate neighbor and respectful representative of the growing community
How to Avoid:
I realize I may sound like a stickler… but this is an important topic. Legality, nosy neighbors, and thievery aren’t the only issues here. We need to stick together and ensure we’re good representatives of the home growing movement. It’s so disappointing when someone blatantly angers their neighborhood with the smell and overt display of weed plants “because it’s legal” and they don’t care. This hurts us all.
Unfortunately, many huge marijuana companies are fighting to ban home cultivation so they have a monopoly on growing. For example, powerful business entities helped convince the state of Washington to ban home cultivation despite cannabis being legalized for all adults (growing even a single cannabis plant in Washington nets you a felony with up to 5 years of prison time, though you can walk down the street and buy weed from a store). There are similar laws for medical marijuana patients in Arkansas, Connecticut, Delaware, Florida, Louisiana, Maryland, Minnesota, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Puerto Rico, West Virginia, and Utah. You can purchase, but not grow at home.
How can it be legal to buy weed, but not plant a seed?! Don’t be ammo for the anti-growing profiteers.
People are trying to take home growing away from us. Because of this, I encourage every grower to be a good neighbor and thoughtful delegate for weed growers everywhere.
Check out our tutorial on how to grow weed in secret. Even if you don’t read that article, here’s the most important stealth advice: don’t smell, don’t tell, don’t sell.
7. Harvesting Too Early
Growing marijuana definitely requires a bit of patience to see it until the end. And no part of the grow will test your patience more than waiting for the right time to harvest your cannabis.
(If you’re in a hurry, most autoflowering strains are ready to harvest less than 90 days from germination)
Harvesting too early will reduce the effects/potency of your medicine in addition to reducing the overall weight. Luckily, it’s straightforward to pick the perfect harvest time.
How to Avoid:
Check out the diagram below for an overview on when to harvest for the highest potency and best effects. If you want the full scoop on when to harvest your plants, see our “When do I harvest my marijuana plants?” page.
Click this picture to see the “when to harvest” diagram.