marijuana watering system

How to Set Up a Drip Irrigation System for Cannabis (2 Ways)

Drip irrigation might seem expensive or complex to set up, but it doesn’t have to be. In this article, we’ll teach you two ways to instal a drip irrigation system to help you cut down on physical labour and grow bigger, healthier cannabis plants.

Learn how to set up an indoor and outdoor drip irrigation system.


With so much hype and info online about grow lights and nutrients, it’s easy for growers to forget about other aspects of their grow, like irrigation. However, without a healthy, regular watering schedule, your cannabis plants are never going to reach their full potential, regardless of how well you train them or how much money you spend on fertiliser.

In this article, we’ll walk you through drip irrigation, one of the simplest and most effective ways to automate the watering and feeding of your plants. With the right drip irrigation system in place, your plants will grow fast and healthy, without you needing to lift a finger to water or feed them.

How Does Drip Irrigation for Cannabis Work?

Drip irrigation, as the name suggests, is an irrigation system that slowly drip-feeds/waters your plants. It’s a low-pressure and low-volume irrigation technique that automatically delivers nutrients and water directly to a plant’s root zone in a very regulated and precise manner.

This seemingly advanced irrigation technique dates back to ancient China; the Fan Shengzhi shu, a Chinese agricultural text dating back to the 1st century BCE, describes a type of drip irrigation using buried clay pots filled with water.

Today, drip irrigation systems can vary greatly in both price and build quality/sophistication. Some of the most popular styles of drip irrigation include:

Drip Line Irrigation

Drip line irrigation uses lines of tubing to deliver water from your faucets to your garden. These systems usually come with a pressure regulator (to lower the pressure of your water and ensure a slow, steady flow of water), a water filter, and a timer to allow you to automate irrigation.

Bottle Drip Irrigation

Bottle drip irrigation is a very simple yet perfectly effective approach to drip irrigation. It uses plastic bottles placed around your garden, close to your plants’ roots, to deliver a slow, steady flow of water. Rather than investing in a drip line system, you can build your own DIY bottle drip irrigation system for next to nothing (instructions below).

Does Drip Irrigation Save Water?

Yes, drip irrigation can save a lot of water, especially when compared to hand-watering, flood irrigation, or spray/sprinkler systems. Because it delivers water in a very controlled manner directly to the roots of your plants, it greatly reduces the loss of water from evaporation. Also, the flow and direction of water in a drip system isn’t affected by wind as it is in sprinkler systems, meaning it can dramatically improve watering efficiency outdoors.

Advantages of Drip Irrigation

Besides saving water, there are many other benefits to drip irrigation:

  • Reduced fertiliser loss: Because drip irrigation delivers water and nutrients directly to a plant’s root zone, it minimises the waste of fertiliser leaching into areas of the soil where it cannot be absorbed.
  • Reduced labour: Installing a drip irrigation system is super simple and much less labour-intensive when compared to flood irrigation. Plus, drip irrigation also reduces the physical labour it takes to water and feed your plants, as it automates the process.
  • Healthier roots: Drip irrigation systems help optimise the humidity of the soil around your plants’ roots, even in large outdoor gardens or fields. This promotes the development of healthier roots, which is key to healthier plants.
  • Slower soil erosion: If you’re a sustainable outdoor grower, drip irrigation is vital to preserving the quality of your soil over time.
  • Easier weeding: The targeted nature of drip irrigation means it reduces the likelihood of weeds sprouting in your garden.
  • Precise water distribution: Drip irrigation ensures all your plants get the same amount of water, every time you water.
  • Reduced disease and/or pest issues: Drip irrigation waters and feeds your plants right at their root zone without wetting their foliage. This keeps your garden dry, helping to keep moisture-loving pests and pathogens at bay.
  • Lower energy costs: Because drip irrigation is a low-pressure system, it can usually be maintained using less energy.

Disadvantages of Drip Irrigation

Unfortunately, drip irrigation systems also have their drawbacks. First and foremost, they can be more expensive than other irrigation systems, meaning they may not be suited to growers with a limited budget.

Drip irrigation systems also leave a lot of room for error. Installing these systems properly requires a lot of knowledge about your plants, their medium, and the local environment (if you’re growing outdoors). Without this knowledge, you may incorrectly instal or run your system, which might ultimately do your plants more harm than good.

Inexperienced growers using subsurface irrigation systems for the first time, for example, may run into issues with over- or underwatering, which can lead to stunted growth, pest issues, and more.

Some other disadvantages of drip irrigation systems include:

  • Salt build-up around the root zone: Because drip irrigation systems minimise fertiliser leakage, they may facilitate the build-up of salt deposits around the root zone, especially if your fertilisers are highly concentrated.
  • Clogging: Drip irrigation systems are prone to clogging, especially if you run into problems with your water filter. Salts in your fertilisers can also build up in your system, causing it to clog.
  • Plastic leakage: The plastic components of drip systems naturally degrade over time, especially out in the sun. When they do, they may leak chemicals into the water, soil, and surrounding environment.
  • Maintenance costs: Regular maintenance is vital to keeping an irrigation system working properly over time. Hiring a professional to do so, or buying replacement parts and repairing the system yourself, may drive up the cost of your grow-op.

Building Your Own DIY Drip Irrigation System for Growing Cannabis

While professional drip irrigation can be expensive, you can easily craft a makeshift DIY drip system at home. Though there are many different ways to do this, we’ll share two of our favourites; a line irrigation system perfect for an indoor grow room, and an outdoor system made using plastic bottles.

How to Build an Indoor Line Drip Irrigation System

Below, you’ll find a list of materials and instructions for creating a simple line drip irrigation system using basic materials. In our experience, these line systems are the best option for indoor gardeners as they minimise the risk of water splashing up onto your plants, which can create an inviting environment for pests and plagues.

  • A faucet close to your grow room: This will be the source of water for your system.
  • Drip irrigation faucet adapter: This adapter includes a backflow preventer, mesh filter, 25 PSI pressure regulator, and a hose adapter. Rather than buying all these pieces separately, we highly recommend this adapter.
  • ½” (1.27cm) watering line.
  • Water drippers: These pressure compensating drippers are perfect for a DIY drip system.
  • Tent stakes to hold the line in place over your pots.
  • Tubing hole punch
  • Line fittings (optional): This collection of T, cross, and corner fittings might come in handy when trying to run long lines through large grow rooms with multiple plants.
  1. Connect your adapter to your faucet, then connect your watering line to the adapter. Open the faucet to ensure the water flows properly through the adapter to the hose and doesn’t leak.
  2. Connect the end of your line to your faucet and run it into your grow room.
  3. Take some time to visualise the best way to run your line around your room.
  4. Use the hole punch to make holes in your line where necessary. We recommend using at least 2–3 drippers for each plant, placed at equal distances around the pot.
  5. Instal the drippers simply by pushing them into the holes in your line. Make sure the drippers don’t wet any of your plant’s foliage or main stem, as this can attract pests and pathogens into your grow room.
  6. Use tent stakes to hold the line in place close to your plants’ topsoil.
  7. Where necessary, use the T, cross, and corner fittings listed above to neatly run your line through your tent/room. To instal the fittings, simply cut your line where you want the fitting to go, and push it into or over the fitting. You may want to warm the line in hot water first to make this process a little easier.
  8. Once you’re finished running your line, cut it (if need be) and use an end plug to plug it.
  9. Turn on your faucet and check your line. Each dripper should effectively drip water into your plant’s medium. Replace any drippers that spray or appear blocked.

How to Build an Outdoor Bottle Drip Irrigation System

The following instructions are for a simple DIY drip irrigation system using hanging plastic bottles. While it might lack sophistication, this system is super easy to set up and gets the job done for next to no upfront investment in materials/equipment.

  • 2l plastic bottles with bottle caps: You’ll need one bottle for each of your plants.
  • Electric drill for drilling holes into the side of the bottles
  • String to secure the hanging bottles above your plants
  • Scissors or utility knife to cut the bottles
  1. Cut the bottom off your bottles completely. Next, drill two holes into each side of the bottle, roughly 2cm down from where you made the cut.
  2. Run a piece of string from one hole to the other, creating a sling from which you can hang the bottles above your plants.
  3. Screw the caps on each bottle, fill them with water, and hang them roughly 30–60cm from the top of your pots.
  4. Gently unscrew the caps on your bottles to let the water slowly seep out. You may want to experiment with opening and closing the cap to find that sweet spot with a nice, slow, steady drip. Also, make sure your bottles are dripping roughly 5–10cm from the stem of your plants, and ensure they’re not wetting the stem or any foliage to avoid problems with pests and plagues.
  5. Refill your bottles as needed.

Drip Irrigation vs Hand-Watering

Drip irrigation has some major benefits compared to hand-watering or other agricultural irrigation techniques. Unfortunately, one of the main reasons it still isn’t the norm for cannabis growers is its significant upfront cost. However, if you’re a serious grower with a bit of a budget and long-term growing goals, drip irrigation can seriously cut down on the physical labour it takes to run your garden, while helping you grow healthier plants and produce even better harvests.

Want to instal a drip irrigation system in your cannabis garden for healthier, more productive plants? Here are two cost-effective ways to do so.

Automatic Watering for your Cannabis Grow

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In this article we’re going to talk about how to set up automatic watering for your cannabis grow, something that can genuinely be a lifesaver for growers that have spent years hand-watering their plants.

Technically, 100% automatic watering is something that still can’t be done, but there are systems in which, if you pick the right substrate, you can water a large amount of plants by simple keeping a tank full of water. This can be helpful if you’re growing a rather large amount of plants so that you don’t have to spend hours watering them all.

If you decide to use this method, keep in mind that your plants won’t grow the same than if you were to hand water them and mind them one by one – if you have lots and lots of plants, then doing this is probably not in your best interest. You can also do this if you don’t have time to water your plants and you only have a few in your grow tent, but keep in mind that the yield will be a bit lower.

If growing in soil you should only begin watering automatically when you’re sure that your plants are drinking a reasonable amount of water per day. In my opinion, I think automatic watering in soil should be used no earlier than when flowering begins, and in a 7L pot your plants should be drinking about half a liter of water a day.

You need to program the watering so that when it waters, it only gives your plants the amount of water they need for one day – you can’t water a 10cm plant with two whole liters as you’d end up soaking the soil, the roots will rot and you’ll probably end up with a dead or hardly productive plant.

If you want this to be more efficient, then you should grow in coco coir which dries up faster than soil, or in coco coir or rockwool slabs. These kinds of substrates drain the leftover water efficiently, so even if you manage to over-water your plants they should dry up soon enough and your roots won’t rot. This means that you’ll be able to water much more efficiently in this medium. Once your plants are big they can dry out our pots or slabs two or three times a day, needing to be watered more than once but this can easily be controlled with a digital timer.

If you’re growing in soil it can be hard to get the timing right, and if you mess it up twice in a row your plants will suffer quite a lot, which is why we recommend using a different kind of substrate with better water drainage if you want to use this automatic system.

Automatic watering is as easy as having at least a 2L tank per plant. You can even prepare enough water for a week, so the most you need to use is 1.5L per plant for 7 days – this is perfect as a week is about how long mineral nutrients can last in water without going bad – if you use organic nutrients you might end up blocking the pipes and you’ll also need to mix them every day as they won’t last more than 24h in the water without going bad.

You need to place a submergible pump into your tank which is capable of maintaining pressure in the pipes, so that the same amount of water comes out of each micro-pipe so that, logically, the plants all receive the same amount of water. You’ll need to install a pipe system that then connects to micro-pipes used for drip irrigation – make holes in the main pipe system for each of your micro-pipes which will then be used to water your plants. You can get pipes that can deal with 16 of these micro-pipes, or drippers such as the Octopussy, which has 6 micro-tubes etc.

Now you need a growing table so that the water can drain out under the flowerpots and flow into a tank which you can then empty – never reuse water from these kinds of systems, and always ensure that your timing is right so that you don’t waste precious water and nutrients, as you’ll basically be throwing money down the drain.

You should have your system set up by now, but you still need to know how much water is being pumped per minute by the pump. Place a glass at the end of one of the drippers and turn the pump on for one minute with the timer to see how much water your plants will be getting per minute. Once you know that, you’ll know how long you’ll need to have it on for when watering. Generally, half a liter per minute is what most pumps give – if you get more than that then your pump is much too big – you need about 1000L/H per square meter of grow with 16 plants in each square meter for the micro-pipes to work correctly.

The last thing you need to do is get an air pump with an air stone, which will ensure that the nutrient mixture and the water is in constant movement and oxygenized – your fertilizers won’t end up accumulating on the bottom and will always be available for your plants once the pump turns on.

Each time you need to fill the tank up again pay attention to how your plants react; if they’re soaked, if they’re too dry, anything that could indicate you need to change your method or water them more/less. They should grow massively and if you’re using slabs they can grow so big that you’ll have to water them up to 3 times a day.

Automatic Watering for your Cannabis Grow – Material needed

Flood table:
These are trays that have grooves in them so that you can direct any leftover water to a specific point, where you can then channel it through a pipe to wherever you’d like or simply leave a tank underneath the hole on the tray itself so that the water can fall down into it. These trays are easy to clean once the grow is done and they’re very efficient when it comes to getting rid of water so that there’s never any leftover water sitting at the bottom of your pots and soaking into the soil. They’re also useful in the fact that leftover water from one plant has the opportunity to be absorbed by another plant, which can help avoid all sorts of salt excess in the substrate and whatnot. There are various sizes available to fit your exact needs.

Water tank:
There are all sorts of water tanks out there that you can use, although we recommend using one that has a lid if you’re growing with chemical or mineral nutrients, as they’ll last the full week and the water will be better conserved if it has a lid – there’s also less possibility of getting fungi infestations and algae that tend to occur when light hits the water- You can also use one of the square tanks without a lid and place it right under the table or inside a grow tent, which can save a lot of space. You need to pick the type of tank but you also need to pick the capacity – the most you’ll use per day is about 2L per plant once they’re fully grown and drinking the most they’re going to drink, so calculate that into about a week of growing and get the right sized tank.

Water pump:
You’ll need a submergible water pump that can give out about 1000L/H per square meter of grow, which is about 16 plants. With this pump you can rest assured that you won’t be pumping too much water per minute, so there’s no need to worry about accidentally over-watering your plants. The minimum amount of time you can program is one minute, and make sure that in that minute no more than half a liter is being pumped out. You need to clean your water pump for every new grow to make sure that it keeps working perfectly – if you wait too long to clean it, it might get all blocked up and break due to the salts used in the water. Make sure to buy a quality pump, and not the first one that you see, as your entire grow will depend on this pump working properly.

Watering pipe:
This tube is used placed in a straight line between two rows of flowerpots or slabs, and the micro-pipes are used alongside the sides of the main pipe – the main pipe is in the middle and then the plants are to the right and left of the pipe, kind of like a corridor. You’ll need one line of pipe per two rows of plants and then you need to place the micro-pipes – there are various models, some of them just need one hole in the main pipe and have 6 different drip pipe endings, some have 12, and some require one hole in the main pipe per drip pipe. You’ll need to pay close attention to the pipes in case they accidentally end up blocked – if you use Ata Clean in your grow about once a week then you can forget about worrying about blockages in the micro-pipes.

Rockwool or coco coir slabs:
Slabs are growing systems that are similar to hydroponics, where the growing medium is wet and then dried often, so it needs continuous watering, and these substrates hardly retain nutrients so you need to add nutrients in almost every watering. You’ll need to plce five slabs on your flood table, cut an X shape in them and place clones in the hole, from 3 to 5 should fit. Place a drip pipe at each plant and all you need to do is pay attention to when it dries up to know how often you’re going to need to water per day.

Air pump:
Air pumps are used to give the water in your tanks more oxygen as well as keeping the nutrients in constant movement, which is something that your plants will greatly enjoy. You’ll need to place an air stone so the oxygen particles are smaller and easier to mix up with the water.

With all of these objects you can easily set up automatic watering for your plants, a small comfort especially if you have a large amount of plants. Don’t forget to keep everything nice and clean so the micro-pipes don’t end up blocked, no algae grows in the tank and no rot begins appearing in the water. Happy growing!

Author: Javier Chinesta
Translation: Ciara Murphy

Automatic Watering for your Cannabis Grow – Learn how to set up automatic watering for your coco coir or rockwool slabs with this informative article.