If you want to grow your own marijuana, you have two basic options for your growing medium: planting your cannabis in traditional pots with soil, or growing hydroponic marijuana. With a hydroponics system, you skip the soil altogether.
Generally speaking, I recommend that total beginners start with soil, because there is more room for mistakes. That being said, hydroponics can produce amazing yields, and it can do so quickly. And hydroponic marijuana growth isn’t too hard to master, even if you are a newbie — so if you want to produce large amounts of weed fast, it is a great method to use.
This guide will teach you everything you need to know in order to grow marijuana successfully using hydroponics. By the time you have read to the bottom, you will know what supplies you need, and you will understand the entire process as well as important tips and tricks. Let’s get started.
- 1 Is Hydroponics Right For You?
- 2 Choosing The Right Environment For Hydroponics
- 3 Basic Equipment Required
- 3.1 Grow Lights
- 3.2 Hydroponics Systems
- 3.3 Hydroponics Substrate
- 3.4 Nutrients
- 3.5 Other Supplies
- 3.6 Seeds
- 4 When Do You Harvest Marijuana?
- 5 Tips & Tricks For Success
- 6 Hydroponic Marijuana FAQ
- 7 Conclusion
- Is Hydroponics Right For You?
- Choosing The Right Environment For Hydroponics
- Basic Equipment Required
- Grow Lights
- Hydroponics Systems
- Ebb And Flow
- Deep Water Culture
- Top Feed
- Nutrient Film
- Passive Growth Systems
- Hydroponics Substrate
- Clay Pebbles
- Coco Coir
- Other Supplies
- When Do You Harvest Marijuana?
- Tips & Tricks For Success
- Hydroponic Marijuana FAQ
Is Hydroponics Right For You?
Before you go out and purchase your hydroponics equipment, you should think about whether or not this is the best method for your needs. Hydroponics is neither “better” nor “worse” than soil — it has some excellent benefits, but it also has some drawbacks as well.
Pros of growing weed hydroponically:
- When you are using hydroponics, you can control the nutrient levels with greater precision than you can when planting in soil.
- Your plants will have a better uptake of oxygen through their roots. Issues with oxygen starvation simply do not exist.
- Your marijuana grows much more quickly through hydroponics. This is because of the increased oxygen availability.
- You can produce larger yields this way.
Cons of growing weed hydroponically:
- It costs more to get started with hydroponics than it does with the soil method.
- Setup is more complicated and time-consuming.
- The maintenance required on your hydroponics system is a continuing time investment.
- You need electricity to power the system.
- Hydroponics is a finicky system. If you make a mistake, you are more likely to lose your cannabis crop.
Basically, with hydroponics, you have a greater level of control. The soil is not there to buffer your cannabis from the nutrients you are adding. On one hand, this is a good thing — you can provide your plants with exactly what they need. But on the other hand, that means that the soil is not there to mitigate your mistakes. If you use the wrong amounts, your plants will suffer.
So before you begin you have to ask yourself, “Am I ready to invest extra time, money, and effort into growing my cannabis?” If the answer to that question is “yes,” then hydroponics will be well worth it. Otherwise, you may want to start with soil, and if you decide that growing pot is for you, you can upgrade to a hydroponics system when you are ready.
Choosing The Right Environment For Hydroponics
First of all, you need to decide where you will grow your pot. A full-size room works great, but you can also go with a shed, a basement, or even a tent. Just keep in mind that if you are using a shed or a tent out back, you need to be able to feed electricity to the system.
Whatever space you decide on, you will need to have room both for your plants and for your equipment. When the plants flower, they will take up around triple the space they did to begin with, so keep that in mind. Make sure there also is enough room for you to get in and work.
Here are a few more tips for choosing a suitable environment:
- Pick a spot which is cool and dry.
- You need to be able to ventilate the space where you are growing your pot.
- The room shouldn’t have windows. You have to control the light and dark cycles artificially.
- Pick a room which offers you privacy (from snooping neighbors for example), but also convenience (since you will have to check on your pot daily).
- Consider painting your walls glossy white or covering them with mylar. This helps the walls reflect light instead of absorbing it.
Basic Equipment Required
A basic hydroponics setup enabling you to start out with around five plants will probably run you anywhere from $300-$500. Shop around for deals and you can save significant money. The following is everything you will need.
First of all, you need lighting. This is one of the more expensive parts of your setup, but spending extra initially to get quality lights is worth it. There are a number of different types of lights you can buy for growing weed:
- Induction grow lights: Similar to fluorescent lights, these are slightly more expensive, but they are also more energy efficient. Their lifetimes tend to be longer as well.
For something more affordable, the best overall option is probably to go with HID lights.
You should purchase blue/green spectrum lights for the vegetative phase, and run them from 16-20 hours a day. Switch to red spectrum lights during the flowering phase, and run them for only 12 hours a day.
Next, you will need to choose a hydroponics system. There are a lot of different options here. Here are some you can consider:
Ebb And Flow:
Also known as “flood and drain,” this is one of the most popular options for growing marijuana, and a good option if you are new to hydroponics. This system has a reservoir which contains nutrients. Periodically, the nutrients from the reservoir are pumped into the containers with the plants. Then they are drained over a half hour period. This draws oxygen to the roots. The simplicity and effectiveness of this system are its appeals. The best substrates (more on that in the next section) for this system are coco coir or rockwool.
Deep Water Culture:
With this system, your plants go in net pots which are suspended over a reservoir. Air pushes the nutrient solution from the reservoir (along with plenty of oxygen) to the plants’ roots. This system requires minimal maintenance, but it can also be very finicky due to root exposure. The best substrates are rockwool or hydroton clay pebbles.
Also known as “drip feed,” this system has your plants in a substrate, and then there is a separate reservoir with nutrients. Tubes are used to drip feed the nutrients into the substrate. It nutrient solution runs back into the reservoir, and is then pumped through the tubes into the substrate again. Use coco coir, clay pebbles or rockwool.
This system uses gravity to deliver nutrients. You have your plants lined up in a long tub, which is propped at an angle. This makes it possible to pump solution from the reservoir to the high end. It then runs naturally down to the low end, washing over the roots of all the plants along the way. It is very effective when used properly, but it can be fussy. Use rockwool or coco coir.
You probably won’t use this type of system, because it is complicated and takes up a lot of room. It tends to be used in professional settings. As with the deep water culture system, the plants are suspended in substrate over a reservoir. This reservoir is maintained at 100% humidity, delivering oxygen and nutrients continuously and consistently to the roots day in and day out. As the roots are exposed, precision control is needed, and it is easy for something to go wrong. But if you are successful with this method, you can have amazing yields. Clay is the best substrate.
Passive Growth Systems:
This is a system where a wick passively draws the nutrient solution from the reservoir into the substrate. The best substrates are coco coir, peat moss or vermiculate. Passive growth systems will have you going through a lot more nutrients, but they are simple to set up and cost-effective, so they may be a good choice for beginners.
Choosing your first hydroponics growing system should involve thinking about the following factors:
- Your general gardening experience.
- The amount of money you have to spend.
- How much maintenance you can commit to doing.
- Your electrical setup.
If you are quite good with plants in general, you may be able to handle some of the fussier systems (like deep water culture). If you are a total newbie, I recommend a passive growth system or ebb and flow. Make sure your system includes a water filter. If it doesn’t, buy one separately and filter the incoming water so that it is free of contaminants.
Your substrate is whatever substance your marijuana is planted in. With hydroponics, that is never soil. Above, I have mentioned a few different types of substrates you can use with different hydroponics systems. Let’s talk about each in more detail.
|This substrate is an inexpensive blend of silica and basalt. It does an excellent job holding moisture. For this reason, it never has to be watered. Indeed, if anything, you need to watch out to make sure it doesn’t retain too much moisture (which can cause mold).
There are a few other things to be aware of with rockwool as well. Firstly, make sure that you steer clear of isolation rockwool, which contains chemicals, as well as dry rockwool, which can cause skin and lung irritation.
Also know that rockwool is alkaline, and that you need to neutralize it before you can put your plants in it.
These are great for newbies, assuming you pick a system they work with.
There are three reasons why clay pebbles are awesome:
|Coconut fiber, also known as “coco coir,” is simply coconut husk. What makes this an effective substrate is the fact that the fiber resists bacteria, mold and mildew.
It retains about as much water as rockwool, so you do need to be mindful not to drown your plants.
|This substance is porous and can hold a lot of water. Heat also causes it to expand. It promotes root growth and helps to aerate soil, but does tend to disintegrate over time. It is more commonly used as an additive rather than as the main growing medium.
Mixing vermiculite with organic potting mix produces an excellent combination that your cannabis plants will love.
|Perlite looks like white pebbles. It is a type of igneous amorphic rock. It is porous, which helps facilitate the flow of nutrients and oxygen, but water drains out of it, so it is unlikely to gather mold or drown your marijuana. Do not inhale the particles as they can cause lung damage.
Perlite is generally used as an additive rather than as the main substrate.
The type of substrate you use will depend primarily on the requirements of the system you pick. There are often a couple of choices for each, so you can then decide from there what you feel will be easiest for you to use. If clay pebbles are compatible with the system you have chosen, I highly advise using them.
The hardest thing about hydroponics is making sure that your cannabis plants are getting the nutrition they need in the appropriate amounts. If you get the proportions wrong, you can kill your weed. Here are some pointers:
- Generally speaking, you can get away with an all-purpose nutrient solution for hydroponics. This will include all the key nutrients along with secondary elements and trace elements.
- It is useful to know how to read percentages on solution bottles. If you see 15-15-15 for example, that is a solution with 15% nitrogen, 15% phosphorus and 15% potassium (the key elements you need for healthy marijuana). If you see 20-10-5, that would be 20% nitrogen, 10% phosphorus and 5% potassium, and so on (everything else in the solution is secondary and trace elements).
- During the vegetative stage, higher amounts of nitrogen are required (especially if the temperature in the room will be under 80 degrees). Midway into the flowering stage, you can reduce the nitrogen, but potassium is extra important.
I use Advanced Nutrients Big Bud fertilizer to keep things simple. Read the reviews and you’ll see it does what it says on the bottle.
Finally, here are some other important supplies you will need:
- Ventilation: You will need an exhaust fan installed near the ceiling along with a filtered air inlet. This is essential in order to maintain the temperature and get CO2 to your marijuana.
- Hygrometer/Thermostat: During the vegetative phase, you want humidity to be around 45-55%. A hygrometer will help you track this. Slightly lower humidity is needed during the flowering phase.
With temperature, try and aim for 70-85 degrees Fahrenheit during the light cycle, and 58-70 degrees Fahrenheit during the dark cycle.
- Timer: You can set up a timer to automate your ventilation and lights. This heavy duty digital programmable timer is what I personally use and recommend.
- pH kit: Use this to make sure your substrate and solution have a pH of around 5.5-6.5. General Hydroponics make the best-selling pH kit on the market. It’s easy to use, inexpensive and highly effective.
You will of course also need to buy marijuana seeds. Many options are available, including feminized seeds, auto-flowering seeds, high THC, high CBD, and regular seeds. For beginners, I recommend feminized seeds. These prevent fertilization, which will ensure that you get the THC content you need.
When Do You Harvest Marijuana?
|You can keep marijuana in the vegetative stage for as long as you want. After you trigger the flowering phase, keep a close eye on the trichomes. The color of the trichomes tells you how much THC is present, which in turn helps you figure out when to harvest.
The “best” time to harvest depends on how much THC you want. THC is at its highest when 60-70% of the pistils have darkened and curled inwards.
Wait until 70-90% have darkened for a more relaxing effect.
Tips & Tricks For Success
- When using rockwool or another substrate that soaks up water readily, do not use a platter, and never re-use your water. If you do either, you could drown your plants and/or invite mold.
- Any system where the roots of the plants are exposed is going to require extra precision in management. While these systems can work well, they can be difficult for beginners.
- Fertilizer is optional, but strongly recommended for higher yields. If you do decide to buy it, it is best if you choose a product which is specifically formulated for hydroponics. For maximum absorption, choose chelated fertilizers, such as those produced by Advanced Nutrients.
- Even if you are using a pH-adjusting fertilizer, it’s wise to regularly check the pH of the water in your system. When your plants absorb nutrients, reactions can occur which destabilize it.
Hydroponic Marijuana FAQ
Q: I have noticed some problems with my leaves involving discoloration/texture/spots/etc. What is going on?
A: There are numerous different possible reasons why marijuana plants may not grow as expected. Some involve environmental conditions, while others may involve pests or blight. For a quick rundown of major possibilities, check the Troubleshooting section of our guide How to Grow Marijuana Indoors.
Q: Can I just use Miracle-Gro?
A: Wouldn’t that be nice? No, you cannot. With Miracle-Gro, you cannot achieve the level of precision you need through all the growth cycles. This can lead to numerous problems involving nutrient burn or deficiency.
Q: Should the water I use be sterile?
A: You can go that route if you want. Otherwise, another good idea is to actually add healthy bacteria to your water after it has been filtered. This may help to prevent fungal infections and other issues.
Q: Why does my pH level change right after I pour water into my reservoir?
A: There are a few reasons this can happen, but generally it is a temporary effect resulting from movement, and should subside after about an hour. Check and see if it does. If you notice any long term changes in pH (which may result when the roots of your cannabis plants release waste products), make sure to take steps to neutralize your water. This is absolutely vital if you want healthy pot plants.
Q: What temperature should the water be?
A: If your room temperature is good (70-85 degrees Fahrenheit during the light cycle, 58-70 degrees Fahrenheit during the dark cycle), your water temperature is fine too.
Hydroponics Takes Time To Set Up, But It Can Result In Excellent Yields
A lot of newbie marijuana growers find hydroponics intimidating compared to soil as a growth medium. That is understandable, since it is more involved, and it does require a higher degree of expertise as well as a more significant investment.
That being said, hydroponics is not as challenging as it appears, especially if you opt for a system and a substrate which are easy for beginners to use. Invest in quality supplies, take your time setting up and learning the ropes, and you should be successful.