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common marijuana growing mistakes

Beginning Pot Grower? Don't Make These 11 Common Mistakes!

common marijuana growing mistakes

We've all done it.

Back in college, my friends and I decided to grow weed one night after finding a bunch of seeds in the bottom of our 20-sack.

It was a brilliant idea.

We absolutely knew that from that point on, we were smoking for free!

You know what happened, right?

Our plants yielded nothing and we did not smoke for free.

So what went wrong?

In short, we had no clue.

Like most first-time growers we did minimal research and just started growing. We figured we'd learn along the way and be fine.

And you do learn. You make mistakes and you learn.

But if you can avoid the most common mistakes, you can learn much faster.

And if you learn faster, you end up with some actual smokable weed much sooner.

Here they are, in no particular order—the most common mistakes beginning growers make.


First: I finally found a great guide on growing that's completely free

A lot of people have asked me to recommend a quality course on growing weed, so I've added the following to this post:

I used to recommend a $50 book on growing, but I recently found a great guide that's completely free!

It's the Marijuana Grow Bible by Robert Bergman and the reason he's now giving it away for free is that he hopes you will end up buying some of your supplies from his store.

Naturally, there's no obligation to do so (and if you're buying lights, I may know of a better store.....hint: you're on it right now...), so go ahead and take advantage of Robert's offer. You're getting a comprehensive 70 page guide that covers everything you need to know to grow weed (indoors or outdoors) and you're paying nothing for it, so why not?

At the time of writing, he was throwing in a second book called Marijuana Plant Care that goes into a lot more detail on nutrients, climate, pruning, pests, diseases, etc.

It's pretty advanced, so if you're just starting out, I wouldn't worry about this stuff yet. Just start with the Grow Bible for now. But once you've got a few grows under your belt, this bonus book can really help you get the most out of your garden.

Head here to get your free guide on growing.


Mistake 1: Starting With Bad Genes

Even without the introduction above, I bet you could have guessed where I got the seeds for my first grow.

I used bagseed.

And I know I'm not alone. The bud you smoked was great, so the seeds in the bottom of the bag are obviously going to make great plants, right?

Um, no.

The seeds are usually duds. If not duds, they're male or hermaphrodites.

To ensure you get healthy plants, get your seeds from a reputable source. Contact us from recs.

With lighting equipment and nutrients and everything else, you're spending a lot of money on this grow. Don't let it go to waste on a plant with poor genetics.

Clones are an alternative to seeds, but another common beginner mistake is using bad clones, i.e. from sick plants or ones that have been treated poorly.

I'd recommend against clones altogether for beginning growers, but if you absolutely insist, only get them from a grower you know and trust.

If you can, inspect the plants the clones came from to make sure they are free from disease. One sick clone will infect your whole garden.


Mistake 2: Using the Paper Towel Method to Sprout Seeds

You've probably read about the “paper towel method” of germinating seeds.

While it is effective, I'd advise against it.

If you use a paper towel, you'll have to transfer the seeds to your growing medium eventually, which means handling them. Any time you handle seeds, you risk damaging them so they don't sprout properly.

Sprout your seeds in the growing medium.

This way you won't have to transfer them later once they start growing. It also puts them at less risk of picking up pests or diseases.


Mistake 3: Failing to Manage pH

Growing weed seems incredibly complicated when you start reading up on the subject, but the truth is, you can ignore much of what you read and still do fine.

One thing you can't ignore is pH.

If the pH is off, your plants will get sick and produce horrible yields. Eventually, they will die.

pH affects your plants' ability to consume nutrients.

If pH is in the correct range, the plants can absorb all the nutrients they need. If it falls outside the right range, they can no longer absorb all nutrients.

  • The correct range for pH when growing in soil is: 6.0 to 7.0
  • For a hydroponic setup it is: 5.5 to 6.5

In order to manage pH and keep it within the correct range you need to get yourself a pH control kit.

Here's a very thorough article on watering and measuring pH.


Mistake 4: Using the Wrong Soil and Fertilizer

A lot of first-time growers will just get some soil from outside and pick up any old bag of fertilizer.

They might get lucky, but probably not.

Soil needs to have the correct pH (see previous point), so test any soil where the pH value is unknown.

As for fertilizer, you're best off using a set made specifically for cannabis.

Here's why.

All fertilizers have a NPK ratio displayed on the bag. The 'N' stands for Nitrogen, the 'P' for Phosphorous and the 'K' for Potassium.

Marijuana plants need a different ratio during flowering than at other times (higher in phosphorous during flowering; higher in nitrogen during other grow cycles), so you can't use the same fertilizer throughout the grow.


Mistake 5: Using Too Many Nutrients

If you've grown before, there's a good chance you've done this.

But it's not your fault.

I'm sure you followed the feeding schedule that was included with your nutrient system.

The problem is: the recommended nutrient dosages are much too high for an indoor garden.

You end up overfeeding your plants and they suffer “nute burn” (nutrient burn).

To avoid overfeeding, go ahead and use the nutrient schedule provided by the nutrient company, but cut all the amounts down to ¼ of the recommended dosage.

So, if the schedule says to use 4 tsp of solution per gallon of water, use 1 tsp (4 * ¼ = 1) instead.

Watch your plants and if they show signs of nutrient deficiency, check the PH first (much of the time, nutrient deficiency is the result of an incorrect pH—see previous mistake).

If it is in the correct range, then you're not giving your plants enough nutrients.

Go ahead and increase the amount of nutrient solution to ½ of the recommended amount.

If that is still not enough, move up to ¾, and so on. Generally, you will never have to go above ½ of the recommended amounts.

NOTE: If you are using LED lights to grow weed, you need to cut back on nutrients even more. More on that in this post.


Mistake 6: Harvesting the Buds Too Soon

Patience is key. But it's not easy.

Seeing those delicious buds hanging from your plants, it's only natural to want to get them down as soon as possible.

But you need to wait for the right time.

Harvesting too early means the buds have not yet reached their full potency. And who doesn't want the most potent buds possible?

Here's a great image to follow (courtesy of GrowWeedEasy):

when to harvest marijuana for best yield


Mistake 7: Not Giving Plants Enough Light

If you're growing indoors, you need artificial lighting. Putting your plants on a windowsill just won't cut it.

If you're just starting out and on a tight budget, you can grow plants using fluorescent lights or even incandescent bulbs.

But you're not going to get great yields.

You don't need to get an expensive 1000 watt LED light per plant, but you do want to ensure that each plant is getting enough light to grow nice and strong and to produce the kind of yields you want.

Check out this lighting guide to help you out.

If you are considering LED lights, we have a post comparing the 4 best 1000 watt fixtures and another for the 4 best 600 watt LED grow lights.


Mistake 8: Overwatering Your Plants

Yes, plants need water to survive. Just like humans.

Also like humans, they get sick if they're force-fed too much water. They start getting droopy and they can even die.

Overwatering doesn't usually result from giving too much water at one time. It results from watering too frequently.

You only want to water your plants when they are actually thirsty.

Here's a simple way to test if your plants need water (for soil or hydroponic mediums): use a finger to touch the top inch of the growing medium.

If it is dry (no wet dirt sticking to your finger when you pull it out), it's time to water your plants. If the medium is wet, don't water!

If you are using DWC or water-based hydro, you want to have large airstones that produce a lot of bubbles.

Not giving your plants enough oxygen is basically the same as overwatering (since having too much water deprives them of oxygen), so make sure they're getting enough O2.


Mistake 9: Being Lax With Security

You don't need to lock up you grow space like Fort Knox, but a little common sense can go a long way.


  • grow in your backyard in view of neighbors or passerbys
  • grow on a window sill where anyone outside can see your plants
  • talk about growing in public (or better yet, at all)
  • don't post photos of your weed or your grow space on Facebook, etc.
  • don't take photos of your plants with identifying info in them, like mail or a magazine subscription with a visible address

Additionally, be mindful of obvious signs, like smell or extremely bright HPS light visible from outside at night. Walk around your house at different times of the day to check if there's anything you might have missed.

When throwing out stems or similar cannabis trash, put it in a small bag along with food waste. Put the bag outside the night before trash pickup, to reduce the chances of someone discovering it.


Mistake 10: Blabbing About Your Grow

This goes hand-in-hand with the previous point. Your best bet is to tell absolutely no one about your garden.

If you have to tell people because you live with them, etc. keep it to an absolute minimum. Every person you tell will likely tell other people and it can quickly snowball out of control to the point where EVERYONE knows.

I read somewhere that every person you tell increases the chances of disaster by 10%.

That means if you tell 10 people, you chances of getting robbed or tossed in jail are 100%.

Think about that next time you feel like telling that cute girl or guy at the club about your grow operation....


Question: What do these 10 mistakes have in common?

Answer: They are easily avoided with a little preparation.

And that brings us to:


Mistake 11: Lack of Preparation

I'll be the first to put my hand up and admit to this one (along with most of the others).

As I mentioned in the intro, the first time I tried to grow marijuana, my friends and I got all excited by the idea of “smoking for free” (while we were taking bong hits, of course) and immediately went out and got some supplies.

We did virtually no research (in our defense, this was the 90s and the internet was not nearly as useful as it is today) and we did not “get to smoke for free” at the end of our first grow.

So if you're thinking about growing weed, do a bit of research first. Reading this article is a great first step, but check out some books or websites as well. There is a wealth of information out there.

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Next article How To Grow Weed With LED Grow Lights - 3 Key Differences From HID Are Hampering Your Grow


Lincoln - September 4, 2023

Actually i used bag seeds ind ended up with a mother i kept cloning fer 11 years. Now another
10 years have gone by and im still at it. Great job really enjoyed the read. Thanks

Brooke Clark - October 20, 2021

Totally true!⭐

Henry - June 24, 2016

@Newfie Nice work! But the sad truth is, most growers don’t see those kind of results, especially not on their first attempt.

Newfie - June 24, 2016

I never had none of the problems you had. Grew my first out door 4 yrs ago and I yielded around 350 grams. That was without ever checking my ph and I only used only grow n bloom and massive for bigger buds. Every year Im getting better amd better. Last year I yielded over 700 grams…roughly a pound amd a half . Its a weed it grows with or without any help from a humans hand.

Henry - June 8, 2016

@Francis I know, but it seems like such a good idea at the time, doesn’t it!

Francis - March 10, 2016

Haha, I did the same as you. Tried growing seeds from my eighth. Didn’t work. I bet everyone whos ever smoked has had the same idea.

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