Do I Need to Use Supplements to Grow Great Weed?

Updated Jul 16, 2021

by Nebula Haze

Which Cannabis Supplements Are Actually Necessary?

“This is what puzzles me most, is all the nutrient companies have a “basic” nutrient line and then they have all the “extra” stuff they want you to give the plant to make big better buds. You can read in forums that growers think the extra stuff rocks and other say that it sucks. The companies all claim theirs is the best. I have not seen a study that shows bigger buds are more potent or even healthier. I wonder if it is like when you compare an organically grown apple to a non-organic apple. The Non-organic one is bigger and shiner but the taste and texture (the important things) do not compare to the organic one. Are all the “extra” really better or would the plant be happier without them?”

~ BuddMarsh

Oooh, this is a great question! So here’s the thing. You need base nutrients, and that’s it. You can get all the way to harvest with the most amazing and top-quality buds ever, with even the cheapest base nutrients and nothing else.

However, obviously, it’s more complicated than just that.

One thing I’ll say, and when you talk to growers who have tried a lot of different nutrient lines, you’ll often hear this…

Your environment and growing skill have a MUCH bigger effect on your final results than the specific nutrient system or supplements you use.

When I’ve tried different nutrients brands, I’ve had a really difficult time telling the difference. A lot of growers will tell you the same thing.

Mineral vs Organic Nutrients

The biggest difference I’ve noticed has been between nutrients that use mineral sources of nutrients vs organic sources. I feel like (in my experience) the mineral/chemical nutrients tend to get slightly faster vegetative growth and sometimes increased bud potency at harvest. Plants with organic nutrients grow slower in the vegetative stage and tend to produce buds with a stronger/more complex smell at harvest. But the difference is relatively small and you can definitely still get really smelly buds with mineral nutrients, and you can get really potent buds with organic nutrients!

These Supplements Work

Besides nutrients, there are some supplements that have a well-established use:

  • Root supplement – something that protects your roots like Hydroguard is really important if growing in hydroponics to prevent your roots from being attacked by root rot. But if your plants aren’t being attacked by root rot, it doesn’t really make much difference
  • CaliMagic supplement – if you’re growing in coco coir, or if using very soft water like reverse osmosis or distilled water, you’ll need to add extra CaliMagic to prevent Calcium and Magnesium deficiencies. However, if your plant doesn’t need CaliMagic, it won’t make much difference. Also, it’s recommended you stop giving your plant a Cal-Mag supplement after your plant has mostly stopped growing new leaves (usually around week 6 of the flowering stage) because Calcium is very important for leaf formation, but isn’t as necessary for making flowers. Too much can get deposited in your buds. Typically your soil or base nutrients will contain some amount of Calcium, so you’re not leaving your plant without any.
  • Silica supplement – Silica is often found abundantly in water, but if you don’t have a lot of silica in your water, your plant’s cell walls aren’t as strong. As a result, if your plant is low on silica, it has weaker stems and is more susceptible to heat stress. However, like the others, adding silica when you don’t need it doesn’t make a difference. Silica can also get deposited in buds, and since it’s actually incorporated in the cell walls, you can’t “flush” it out like some other nutrients. Therefore it’s recommended you stop giving a silica supplement after you see buds forming. I’m of the opinion that there’s no need to use silica since you can hold plants up with plant yo-yos, tomato cages or stakes. Why put something into the plant (that you know can get deposited in buds but isn’t necessary for healthy growth) if you can use a mechanical solution instead?
  • PK Boosters, Bulking Formulas, & Shooting Powders – These add high levels of P & K. If you’re not giving your plants specially made flowering nutrients, they need another source of extra P and K. So for example if someone is growing in soil without adding nutrients, a PK booster is perfect for the flowering stage to make up for what the plant has used up in the soil. These types of products often contain naturally occurring plant hormones to help stimulate flowering which are not listed on the label. The downside is these hormones can sometimes cause plants to herm or grow male flowers (which can result in seedy buds), though typically that only happens with strains that are already prone to herming.

So the main theme is that, when it comes to supplements, the ones that make the biggest difference have specific uses for the plant. If the plant doesn’t need it, adding a supplement can sometimes do nothing, or even worse it could hurt your plant. For example, if you add a PK booster when you’re already giving full strength base flowering nutrients, you could burn or even kill your plants!

Then you’ve got supplements that don’t necessarily “fix” a problem, but “enhance.”

Which Supplements “Enhance” Buds or Growth?

  • Sugar and Carbohydrate-based supplements – These claim to increase potency and trichome production, and may increase bulk. However, I’m not 100% certain they add anything but sugar to the buds. The reason I say that is if a grower uses a lot of these types of supplements the plant can start oozing sugar sap. If you taste the sap, it’s sweet and not potent at all. I almost wonder if that extra “weight” is just sugar being stored in the buds and doesn’t necessarily add to the potency. Some of these products, like the Botanicare Sweet Carbo Line, not only include sugar, but also certain terpenes and esters that are stored unchanged in plant buds, giving your buds unique subtle flavors and a generally sweet smell.
  • Other Enhancers – Then there are the more nebulous types of supplements that are meant to give overall improvements. For example supplements with Amino Acids, Vitamins, and other non-essential plant compounds. These are a lot harder to measure the results. I’m sure some of them do what they say, while others are basically snake oil. It’s a lot harder to prove one way or the other with these because it’s difficult to test unless you do a big side-by-side controlled experiment with a bunch of plants. And unfortunately, the industry just hasn’t quite reached that point yet!

Improve Smell

Although I haven’t tried this yet, I’m really intrigued by Botanicare’s Sweet Carbo line. According to Botanicare:

The natural esters in Sweet are easily absorbed by the plant, but are not broken down further once deposited within the plant tissue. This means that as new flowers develop they will contain small amounts of these natural esters which contribute to the overall flavor and aroma of the finished product.

They offer citrusberry, and “raw” (which is just a generally sweet smell). These should be used throughout the flowering stage to help build smell/flavor in the buds as they mature. However, since these contain a small but significant amount of magnesium, they should not be used while flushing during the last 2-3 weeks before harvest. At this point, the smells have already been deposited into the buds. Another cool thing about these supplements is they contain amino acids and some other enhancers, so it’s kind of like getting a lot of different products at once.

The Botanicare Sweet Carbo line offers cannabis supplements to make buds smell like citrusberry, or “raw” (a generally sweet smell)


Bloom Enhancers

The jury is still out and which is the most effective supplement, but many growers are happy with bloom-promoting supplements that include sources of…

  • amino acids
  • humic acids
  • vitamins
  • trace minerals
  • often contain unlisted ingredients (including plant hormones)

I personally don’t use this type of supplement so I can’t recommend a particular one, but some of the most popular cannabis supplements based on this type of formula include…

Note: When possible, try to get all your nutrients and supplements from the same company. This greatly reduces the chance of getting unexpected reactions between the different products. Some companies don’t “play well” together.


When it comes to bud quality, it’s important to give the right nutrients so that your plant is healthy and vibrant, but other than that I think focusing on the environment (especially maintaining high light levels and proper temperature/humidity) have a much bigger effect on your final bud quality than your specific brand of nutrients or the specific supplements you use!

Cannabis buds after harvest drying upside down


Jump to…

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