Nutrients & pH Up and Down
Nutrition and pH Balance
Your Plants are Sprouting, Now What?
The marijuana seeds will provide all the nutritional value needed for your plants up through the first couple weeks after it breaks through the surface of its growing medium. After that though, it will be completely up to you to make sure your plants are properly nourished. With the right nutrients, feeding schedule, and an understanding of pH balancing though, this is all pretty intuitive.
As with all life, marijuana requires certain nutrients to be able to function correctly. Nutrients help give your plants root and branch strength, improve absorption of light and water, and aid in rich bud development. It is highly important to make sure your plants are getting all the nutrients they need, so that they can become what they were meant to be: efficient THC factories.
The nutritional requirements for weed in particular are trace amounts of over 20 different elements (often referred to as micronutrients or micro) and an abundance of the big three building blocks: nitrogen (N), phosphorous (P), and potassium (K). Each of these nutrients serves its own unique purpose and should be introduced to your plants nutrient solution at the appropriate times.

Feeding your marijuana plants is a simple process. All it takes is adding nutrients into the fresh water reservoir of your hydroponics system, thus converting it from just plain water into a nutrient-rich solution your plants will find quite delectable. Though there are a wide variety of nutrient manufacturers out there, most feeding formulas are based on these 3 basic nutrient solution types.
- Micro – Used at all stages of marijuana growth. It provides the multitude of nutrients needed in smaller quantities such as Calcium, Iron, & Silicon.
- Grow – Used in the vegetative stage. It is heavy in N which greatly helps the plant expand and increase greatly in overall size. Grow usually contains moderate amounts of P and K as well.
- Bloom – Used during the flowering stage. Heavy in P and K; little to no traces of N because it is detrimental during the flowering stage.

Recommended Nutrients: General Hydroponics Flora Series
When I began growing, I just ordered my nutrients with my hydroponics system and lighting kit. It came in a powdered form, had no clear directions on what amounts to use and how often I should be using them. Though I think my plants were probably alright for the most part, they were clearly still being neglected in some ways such as suffering from nutrient burn and weaker stalks.
On my third grow, I decided to do a lot more research into nutrient formulas and seeing what other growers used and had success with. The particular lineup that seemed to be the most promising based on other grower’s reviews was a liquid-form nutrient called General Hydroponics Flora Series, so I decided to give it a go.
I have to say, it had to be one of my best decisions in growing yet. Since then it’s been a brainless task to fatten my plants until they are exploding with cannabinoids. It also gives you a feeding schedule, so you know exactly what nutrients to put in and when. It also does an excellent job at regulating the pH in your system and very rarely do I have to balance the pH myself.

The pH Scale and Its Effect on Nutrition
The pH scale is a measurement system used to determine how acidic or alkaline a solution is. This is important to understand in any type of grow but especially for hydroponics as neglecting pH can quickly damage your plants or wipe them out completely. If the pH of your nutrient solution isn’t at the correct range, your plants won’t be able to absorb any of the essential nutrients it needs, also called nutrient lockout.
So what do you need to know? Well, let’s start with the basics when it comes to pH:
- If pH = 7, it is considered pH neutral. Pure water is neutral at 7.0 pH
- If pH < 7, the solution is considered to be acidic
- If pH > 7, the solution is considered to be alkaline.
Hydroponic marijuana likes its water slightly acidic and needs to within the pH range of roughly 5.5 – 6.5 to have access to all the nutrients it needs. Staying in this range consistently is critical.
Going outside of the optimal range a day or so won’t instantly kill your plants or anything, but you will want to make sure you correct it as soon as possible. Think of going outside the pH range as zipping up your marijuana’s mouth. If you zip it’s mouth, it can’t eat, but you won’t damage it unless it can’t eat for an extended period of time.
Obviously, there’s a big problem if your plants can’t get nutrients from the solution, but the good news is that it is pretty simple to keep pH under control and your plants thriving in a positive nutrient-rich environment by measuring and balancing pH regularly.

How to Measure Your Solution’s pH
Since it is clear that keeping the pH balanced within the tank is of critical import, it follows that you are going to need to be able to measure the pH of your system to see if things are OK or a disaster’s a brewing.
When I began, I was using paper strips to measure the pH. They seemed like they were working pretty well until my first grow died completely to root rot. Analyzing my failure, I thought my solution may have been far too acidic and the strips weren’t giving me a very accurate picture of what was going on inside the tank. After all, the paper strips weren’t very accurate even at their best. I had to judge the pH by comparing the strips color to a standard color chart, which could be off by 0.5 – 1.0 pH. That could be the difference between delightful and death.
I decided I wanted something a little more powerful and accurate, so I went exploring the net to see what sort of pH measuring tools people recommended for hydroponic use. That’s how I found out about the Milwaukee PH600 tester. I checked it out on Amazon, and it was really cheap so I bought it to see if I could improve my grows at all with it.
The very first thing I did when I got the PH600 was compare it to the results I was getting from the strips. In that first test, the pH of the strips said it was around 6.0 (perfect), but my new tester was saying it was 3.8 (epic disaster)! It made me wonder how long I was exposing my first grow to crappy pH levels, and how a lot of heartbreak probably could have been prevented if I had just had the right pH measuring tool to start with.

Balancing with pH Up and pH Down
Once you have a reliable way of measuring the pH of your nutrient solution, you’ll need a way of bringing it back into balance if the pH goes outside the optimal range. This is a very straightforward process that usually just requires pouring a liquid or mixing a powder into your nutrient tank. These powders and liquids are unsurprisingly referred to as pH Up and pH Down or pH buffers.
Like nutrients, I’m not a big fan of the powdered stuff. That’s mostly just preference though, and I have no evidence one way or another about whether liquid or powders perform better.
That being said, the pH up and down I use are the buffers from General Hydroponics as well. To me, it just makes sense to use the same company for the nutrients and pH control because the 2 components are so closely related.
With the Flora Series nutrients, I don’t need to balance the pH all that often; once or twice a grow if that. I measure my pH every day for a few days after I’ve cleaned the tank out and added nutrients, and I measure every other day after that until I clean my tank and add nutrients again.
You’ll have to decide which nutrient and pH lineup you want for your grow, but if you want something that’s virtually foolproof and produces amazing results then I definitely recommend General Hydroponics. It’s been a champion for me.
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Nutrient Lineup
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pH Measuring Tool
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pH Balancing Formula
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Dear Sir,
I’m having problems with the ph in my hydroponics system. I have followed your guide, purchased all the materials you have suggested, and still am having trouble with the pH. The pH in my tank steadily gravitates to 6.8-7.0 everyday. I will add pH down to get it back to 5.8, and the very next day, the pH has returned to 6.8-7.0, any suggestions on what I am doing wrong, or any suggestions on how to correct this? My seedling is still bright green and standing tall and pretty, so I am not overly concerned. I have only one seed in the 6 pod setup because I didn’t want to waste all my seeds on the first attempt. Second, I was gonna be brave and attempt cloning on my first attempt. I purchased seeds exactly where you suggested. Any advice would be greatly appreciated. Thank you.
Jeff-
PH fluctuation is normal in a hydro setup, whether the plants are healthy or not. In my experience, healthy plants tend to gravitate up, while unhealthy plants will gravitate down. This is just my experience though, I’m not sure this is universal. In any case though, don’t worry about the pH, just keep balancing, you’re on the right track it sounds like.
I’ve never cloned myself, so I can’t give any advice really. If you do clone, you’re going to need a separate room to keep the clone (mother plant) in permanent vegetative. Have you started flowering on your grow yet? If you’re going to attempt it, from my understanding it’s best to get cuttings as you transition to flowering from veg. Again, this is something I don’t have experience with, so you’ll have to give it a shot yourself. Attempting to clone shouldn’t hurt your current grow at all, so I don’t see any harm in trying it out if you have a place to put the mother.
Gimp
Thanks, but to my disappointment, when i came home this evening, my seedling had slumped over to the side, it is still green, i propped it up to give it support, i have started spraying the seedling twice daily with pure ground water to give it the dew effect from outside, would this be the cause? otherwise, i will continue with the pH down as you have suggested. Also, it is in a very very young stage, just a stem with two long leaves and two short leaves and the top, that’s all. I started the germination and growth process about 2 weeks ago. When I say ground water, I mean that I have a well, I am not on city water, but I use distilled water for the tank and feeding. I haven’t yet progressed to the 2nd feeding as I was told to do this monthly.
Sometimes your growing medium like rockwool and the hydroton can raise your ph just keep balancing and eventually it will wash out all the base.and keep in mind that you need to only water 1 to 2 times a day during the germination stages even with sproutlings.when they establish a better root system they can have lots more water.My system is the same as the gimps and I water at 7 am and then at 7pm with no signs of stress.I dont leave mine on a drip at all.that away I can make sure all waterings stay at a ph of 5.8. Also once the majority of your root systems hits the water in the tank you can stop manually watering and by then your growing mediums should of flushed all of the base in them,and your system will stabilize.