How to Feed Weed Plants Step-by-Step

Learn how to feed weed plants step by step in this article!Water and nutrients, aside from light, are essential to plant growth. Feeding the plants should be taken seriously, and you should try to feed the plants the best food you can buy. I always joke that my plants eat and drink better than I do, which is definitely true. 

It’s not very hard to feed weed. There are so many products out there, so many solutions, it becomes confusing. In reality though, weed really only needs a few essential things. Understand what the weed needs, and then it’s easy!

There are a few important things to consider when it comes to feeding – here are the main ones:

  • what kind of soil you’re using
  • the pH of the feed and run off
  • the PPM of the feed
  • proper ratio of Nitrogen-Phosphorus-Potassium
  • avoiding over and under watering
Look no further than this article to learn how to feed weed plants step by step. 

Starting With Soil

First, let’s start with the soil, as that is the absorption medium for the nutrients. If you are looking to research hydroponics, check out our hydro weed growing guide. Soil comes in all kinds of varieties. There are huge differences in the ratio of nutrients (nitrogen phosphorus and potassium). Moisture content, the composition of the soil (more or less clay, sand, loam or humus), and also the drainage characteristics are also differentiating factors.

Let’s start off with the nutrient composition. You want to have a higher ratio of Nitrogen than anything else at first, as cannabis in veg state loves nitrogen. I like 20:10:10, in terms of the N:P:K ratio. I have seen soils enhanced with different microbial cultures such as mycorrhizae; they are expensive, but if you want to do a proper organic grow, that option might be interesting.

In terms of the composition of the soil, you want something which does not hold water for too long, but also does not dry out too quickly. It should say on the packet whether the soil is a wet or a dry one, try to go in the middle. Soil which holds water will damage the roots by suffocating them. On the other hand, the ones which dry out too quick need to be watered more often.

Controlling Water Quality

Starting with good water is always a good way to go. One of my buddies goes out to a little town not far from here with a bunch of jugs. He fills them all with natural spring water, and then uses that to water the plants. This is a great thing to do if you can find a natural stream near you. 

Using clean, pure water is the best way to learn how to feed weed plants.

If not, I like to use Brita Water. There are definitely downsides – putting more Fluoride into the water, but I find it gives me a nice clean slate while still retaining some beneficial characteristics. It leaves a base layer of minerals but takes out all the hard metals and chlorine. 

The point is, don’t just use your tap water, that’s filled with chlorine and perhaps even heavy metals. These things will surely poison the plant, and result in a lower yield. I don’t recommend using reverse osmosis water though, as that really has absolutely nothing in it, unless you have a very comprehensive nutrient stack.

If you MUST use tap water, then there is a safe way to do it. Fill up a jug of tap water, and then let it sit on your counter top for at least a day. The chlorine will evaporate out, leaving you with some decent water. It might still be packed full of hard minerals though, so use a PPM meter to see how much is dissolved in there. If it’s past 1000, it’s really high. I like to have it no more than 800.

pH Level

Controlling the pH is one of the most important things with water. When we talk about pH, it’s easy to get a little bit lost, because it’s an idea so far removed from reality. Basically it’s the amount of freely available hydrogen ions available in the water. The higher the pH, the more “basic” it is – alkaline, and the lower the pH, the more acidic it is. 
On a scale, lemon juice and stomach acid might be on the lower end – acidic – of the scale, around 2-4 pH, while something like lye – sodium hydroxide – is very basic, or alkaline, with a pH of 12. Both ends of this scale are bad, and will react negatively with biology. For a soil based system, you want to have it in the 6-7 range ideally. I have heard some say that the range is 6-8, but I like to keep it 7 or under.

If it gets out of this range, the plant will not be able to absorb the nutrients in the water. This is called nutrient lockout, and is dangerous because it starves the plant of macro molecules. Therefore, it’s good to have a little electric pH tester. You can get these on Amazon for pretty cheap nowadays, it’s a worthwhile investment. The ones I have are years old and still going. Sometimes, you will need to re-calibrate the instrument, but all the items needed to do that are usually included. If you are interested, check out my pH meter buying guide for more information. 

Another good thing to do is to test the runoff. This is the liquid that comes out the bottom of the pot after you water the plant. Checking the pH of this liquid is always good because it gives a good signal as to the status of the soil’s ecosystem. If it goes out of whack, then adjust the feed as necessary, and then check again next time. 

To adjust pH, there are tools for pH up and down, just chemicals you add to the water. Check out my pH modulators page for more information about these. 

VivoSun pH and PPM Meter Combo

This is a great package I recommend to beginners. They both work great, calibrated out of the factory. It’s a great price, especially for both of these devices. Made specifically for working with marijuana and measuring weed feed, these are your tools of the trade.  I started off with this package, and used both of these sticks for a few years. They are quite reliable and the PPM meter can easily be re-calibrated for long-term stable use. 

How to feed weed plants well starts with a good pH and PPM meter.

PPM Level

The PPM is not nearly as interesting or important as pH, but you still want to check it. I like to check the PPM if I switch water sources the first time, to know what I’m starting with. Also, if you switch nutrient stack, it’s also good to check the PPM after, to see if the feed PPM is still within bounds. 

In case you didn’t know, PPM stands for parts per million. It’s a number which compares the concentration of a macro molecules versus the concentration of water molecules. What this does is indicate the hardness of you water (if measuring before you add nutes), or the concentration of your nutrient macro molecules (if measuring after you add nutes). 

Basically, just make sure that you’re starting from a pretty low number, say 200-800 PPM when you have clean water, and definitely no more than 2000 after nutrients are added. As long as you start off with good clean water, and you don’t overdo the nutrients, this shouldn’t be a problem. 


If you think this is complicated, you ain’t seen nothing yet. The wacky world of nutrients is still right ahead of you. There are so many different nutrient products, and they all have their own little function that they fulfil. It’s easy to get caught up in the hype surrounding this or that product. There are a few nutrients on the market that I think are just fantastic and you can’t go wrong with. I recommend you start with these, the tried and true. My “Best Cannabis Nutrients for Soil” buying guide should get you started on the right track.

When it comes to nutrients, we are again going into the N-P-K (nitrogen, phosphorous, potassium) ratio. These ratios need to be different depending on the state of the grow. For example, vegetative growth requires more nitrogen than other nutrients. Blooming or flowering growth requires more phosphorous than any of the other components. For this reason, you will want at least two different feeding regimens – one for vegetative state, one for flower state.

Advanced Nutrients - Iguana Juice

Organic, filtered from natural substances using pure filtration processes – the best nutrients in the world. I started off with other products, but I’ve slowly advanced to Iguana Juice, and it gives me fantastic results. Start with the Grow phase bottle, and then proceed to the bloom bottle once the plants start flowering. Really doesn’t get any easier to give your plants pure nutrients than this. Very concentrated, very potent, and completely organic.

Organic v.s. Artificial Fertilisers 

There are the chemical feeds and there are the organic feeds. Both can deliver really good results, and clean marijuana. I think that the option between the two is up to personal preference. I started growing with organic feed, for example, but found it to be quite gross. The typical organic stack will include insect frass, liquefied fish, and the likes. It’s pretty gnarly, and smelly. 

The way that organic systems work is you feed the soil culture rather than the plant. There are these little organisms called mycorrhizae which collaborate with the roots to form a strong ecosystem. They provide the roots with essential nutrients, coming from all the insects and fish you feed them. They work to stabilise the environment too, so it technically is more forgiving to start off with an organic setup.

If you want to try growing organically, I recommend you get an organic growing kit. Just be aware that there is a definite smell to the whole ordeal. 

At the end of the day though, the lines are often blurred between the two modes of operation. There are some nutrients form Advanced Nutrients which essentially work like non-organic chemicals, but are certified organic. These are the nutrients I use today, because they are just top quality. It’s up to you what you want to use, just make sure you get good nutrients. Usually good means expensive, but trust me, it’s worth it to get the best.

Avoiding Underfeeding and Overfeeding

Some people baby their plants too much and result in drowning the roots. Others have the opinion that if you leave the soil dry for a little longer, it will encourage root growth. I have been both of these people, but it’s best to be neither. Finding a proper feeding schedule will take some time, but once you get it, the process becomes automatic. I have a 10 Liter watering jug which I use on my legally grown 4 plants. I end up refilling it every 2 days or so, it’s a good schedule. I recommend having a nice big watering jug so you don’t have to mix nutrients every day.
Rather than waiting for the plant to wilt, it’s important to act before it’s necessary. The best way to do this, is to just develop a routine. I think watering every 2-3 days is prime, but your mileage will vary. Lifting the pots is probably the best way to check if the plants need water. Another way to check if the soil is ready is putting your finger in around an inch deep. If you find that it’s dry and crumbly for the first half inch, it’s definitely time. 
Both under watering and over watering will result in these sickly looking droopy leaves. Sometimes, the stalk itself will also start to bend, seeming as if the entire plant is ready to die. Feeding the plant will restore life to it in a few hours though, just don’t let this happen too often.
Over watering is a slow asphyxiation of the plant. If you keep applying water, this moisture will displace all the air pockets from the soil. Plants need air to breathe, and a lot of it comes from the roots, so constantly watering results in lack of air. Although the effects won’t be deadly immediately, this will take a huge toll over time. 
A big difference between the symptoms of over versus under watering can actually be seen in the leaves. It’s the scaliness/plumpness of the leaf which you are looking for. If you rub your finger on the leaf, and it’s dry, scaly, kind of papery feeling, it’s probably dried out. On the other hand, if it is looking swollen or full looking, it’s definitely over watering. I think you will know anyways, judging by your routine, but in case you don’t, try those rules of thumb. 

Concluding How to Feed Weed Plants

What a journey we have been through in this article. I hope that you have learned a lot about how to properly water marijuana. It’s a hard topic to understand without any knowledge whatsoever. I hope that this article has given you a good base understanding on how to feed weed plants. If you have any questions, either contact me personally or leave a comment, and I’ll try to get back to you. Have a good one, and happy growing!

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