In this blog, we’re talking about growing with drip irrigation systems. We’ll cover the basics, and we’ll go into more detail about the different kinds of drip irrigation available.
And, we’ll give you our 6 Golden Rules for successfully setting up and using drip irrigation in your grow room.
But, first, let's have a look at some common questions surrounding drip irrigation.
How Does Drip Irrigation Work?
Drip irrigations work by providing nutrients directly to the top of your growing media. They are usually automated using a timed irrigation pump to feed your plants as needed.
Drip irrigation can be set as a run to waste system or recirculating as required by plant demands and the type of media used.
What Are The Different Types of Feeding Systems?
There are many methods of growing and feeding systems that can be used effectively to grow your plants, including:
- Hand watering,
- Pure hydroponics,
- Bottom-fed systems,
- Deepwater culture,
- Flood and drain.
We’ve used them each and every one. But above all, we love a good drip system.
Timed irrigation can be tailored to provide the right amount of strength and nutrients to your plant’s roots.
Probably the most versatile system going, drip systems can be used for most growing methods, including organic growing and pure hydroponic drip systems.
What Are The Benefits of Drip Irrigation Systems?
There are lots of benefits to using drip irrigation systems to feed your plants:
Drip systems allow for precise control of nutrient levels within your plant’s root zone. You can measure runoff levels and fine-tune your feed and irrigation times to suit the plants’ size and stage of growth.
This is the best way to achieve healthy, fast growth and great yields. And, you can even ‘steer’ your plant to vegetative growth or flowering production using different feeding regimes.
The other obvious benefit is that they do the watering for you. This gives you more time to spend on other jobs around the grow room – or to simply chill out!
Once your drip system is set up, the automated nature of the feeding method means you can leave the grow room alone for a few days and your plants will still get everything they need while you’re not there.
Drip irrigation can generally be split into 2 main types – Run To Waste and Recirculating Systems.
As the name suggests, run to waste systems collect and dispose of runoff, rather than running back to the main reservoir.
It can be a simple as raising pots above a container and emptying the waste as necessary.
A more elaborate approach involves pot stands running to a dripper ‘brain’ that will pump the run-off (waste nutrient) to a separate tank/reservoir or straight down a drain if available.
The latter is more suitable for running multi-plant systems and large setups.
This is our preferred drip irrigation method as it delivers fresh nutrients each time the plants are fed and helps stop the build-up of any excess nutrient within the root zone.
Think of feeding your plants like a conveyor belt: the nutrients head past the plant’s roots to give them exactly what they need at that time.
We prefer this to feeding plants the same solution over and over again as the water may contain depleted nutrients.
Obviously, you’ll need to dispose of this wastewater, and for that reason, some suggest this method is wasteful.
However, that need not be the case. By using the right media and carefully automating feed times, the waste can be minimal.
Furthermore, you can recycle the wastewater in your garden or greenhouse, or feeding other plants and lawns.
These drip systems recirculate the water so the run-off returns to the same tank it is fed from.
In turn, the waste runs back down into the reservoir below.
These systems are great for a first try at drip irrigation as they are simple, guaranteed leak-free and can be used with almost any media.
Recirculating systems are particularly suited to free-draining media, such as clay pebbles. This is because run to waste systems would waste too much nutrient solution to be economically viable.
Note - the Wilma systems can be adapted for use as a run to waste system by simply adding an external reservoir and some more pipework for the pump and nutrients. You can use the bottom tray/tank to only collect the run-off from the pots and empty as necessary.
The best irrigation systems can be measured on the needs of your grow space and personal choice.
In our experience, some of the best drip systems are homemade and can often outperform expensive off the shelf options.
They can be customised to suit your room size and layout, and are usually very cost-effective.
Let’s have a look at some of our favourites:
Critical Drip System
The Critical Drip System is an effective all-rounder. Its modular nature means it can be used in any size or shaped grow room, and its low-level design stops you losing valuable headroom.
Moreover, the Critical Drip System is versatile. It can run as both run-to-waste or recirculating feeding.
It's available as a 'lite' system for 4-8 plants or as a high-pressure system from 12-48 plants.
Wilma 4 and 8 Pot Systems
The self contained, recirculating drip systems can be used with any media, such as clay pebbles or soil.
And by including an external tank, Wilma systems can also be used as run to waste too.
We love helping people design and build custom drip systems.
Get in touch and we’ll support you in getting the best from your own drip system - whatever your budget.
It’s incredibly important that you work out how long to run your drip system for. And working it out includes the consideration of lots of variables.
For instance, you need to take into account:
- Substrate choice,
- Pot/container size,
- Plant size,
- Stage of growth.
Generally, your irrigation duration can be determined by turning your pump on when your plants need feeding. The best time to feed is when your pots are getting lighter but not fully dry.
Then, time how long it takes for run-off to come out the bottom of the pot. Once you've worked that out, it will determine how long your pump should be on for. Although, it will increase as your plants get larger.
For a more comprehensive assessment of measuring runoff time, see our 6 Golden Rules for Drip Irrigation below.
Drip-feeding with different media types
The frequency of your feeds (how often your pump is on) depends massively on the media being used and pot size.
But it should be the time it takes for the pots to achieve the same moisture levels (weight) it was before the last feed.
In free-draining substrates, such as clay pebbles or rock wool cubes, irrigation frequencies can be as often as every hour or two when plants are feeding heavily.
And in larger pots using substrates such as coco and soil, they often only require water once or twice a day. Sometimes up to 2-4 times a day for smaller pots of coco.
Interestingly, many organic growers never irrigate to the point of run-off, preferring to keep the soil at a near-constant moisture level all the time.
Some soil growers using large pots only irrigate every few days and will just turn the drip system on manually when a feed is required.
Let's take a look at our 6 Golden Rules of Drip Irrigation to keep your plants healthy and produce high yields.
1. Only irrigate when your plants are awake
You should feed your plants an hour after the lights have turned on. This gives your plants a chance to wake up, start transpiring and use any remaining nutrients in the pot.
As with humans in the morning, it can also take plants a while to get going. But giving them an hour of light before feeding allows the processes within the plant to start happening and nutrient demand to begin.
Time your last feed for at least two hours before the light goes out, so most of the nutrient and water is used before the plants shut down for the night period.
Irrigating right up to the night cycle can cause your plants to be over-wet through the night and still wet in the morning, which can lead to root damage issues and sluggish growth rates.
2. Establish your plants before drip-feeding
In some growing media, such as coco and soil, it’s essential to let plants establish themselves in their pots and develop good roots before feeding via the drippers.
It’s best to hand water coco or soil plants for a week or two after potting. This allows for precise control of individual pots while the plants establish.
But, when using some free-draining media such as rock wool or clay pebbles, this only needs to occur for a short time or isn't necessary at all.
3. Measure runoff volume
It’s important to get the amount of runoff right too. Too little runoff can lead to nutrient deficiency. While overwatering can damage your roots - not to mention wasting your nutrients.
Aiming for around 10-20% runoff with most media ensures your plants have everything they need and any unused nutrient in the pot is flushed out.
To measure runoff, you can measure the volume in relation to the amount that’s been fed, or by timing how long it takes for run-off to occur.
- Measuring run-off by volume:
The easiest way to do this is to keep an eye on your main reservoir and your run-off/waste tank and feed as appropriate.
For instance, if you've used 50l of 100l reservoir, then you want roughly 5-10 litres of runoff in your waste tank.
And If you’ve used the full 100l of nutrients, then you want 10-20 litres runoff.
If you have too much, then cut the frequency or duration of your feed times. Or, if you have too little, increase as needed.
- Measuring runoff by time:
This method can be a little trickier and does depend somewhat on the media and pot size being used.
Measure how long it takes for run-off to occur when your pump comes on (you’re aiming for 10-20%).
For example, if feeding plants for five minutes, you want runoff to occur after 80-90% of the feed time has elapsed.
This means you want runoff to occur after the pump has been on for four to four-and-a-half minutes.
This method is harder to judge when using multiple feeds throughout the day because the first feed will not get much runoff. While later, the feeds will produce more runoff.
In this situation measuring your run-off by volume is more suitable.
4. Measure run-off nutrient levels (EC) and pH:
When using a hydroponic substrate or coco, you can measure your EC and pH levels to help fine-tune your feed levels according to your plant’s current requirements.
In fact, this is one of the main advantages of using a run-to-waste drip system over other methods. Regularly measuring run-off levels and reacting accordingly can eliminate overfeeding issues and prevent a lot of problems before they occur – ultimate control!
- EC Levels:
Ideally, you want the run-off EC levels to be the same or slightly higher than your input EC levels to ensure your plants have everything they need, and a little more.
For example, your plant’s demands are highest during early to mid-flower. If you’re feeding an EC of 1.6-1.8, you want your run-off EC levels to be 1.8-2.2.
If your EC levels are coming out lower than your input EC levels, you know you can add more feed and push your plants a little harder to achieve a better yield.
If you do need to raise your EC, do it over the course of a few days to a week as an instant big increase can be detrimental.
On the other hand, if your EC levels are starting to come out a lot higher than your input levels, you need to back off to prevent overfeeding.
- PH Levels:
Similarly to EC levels, you can measure your pH levels and react accordingly.
pH levels change within your root zone, so we’re looking for the levels to swing as different nutrients are more available at varying pH levels.
Ideally, a pH range of around 5.8-6.2 is desirable. You can measure your pH runoff levels and if they start coming out a little high then you can drop the pH of your input nutrient.
For hydro and coco drip systems you should never drop your pH below 5.5.
Note – these levels being right is dependent on getting the right amount of run-off.
Always check run-off volume. If there isn’t enough runoff, simply increasing it can rectify pH or EC levels within the root zone.
5. Choose the right pump
Choosing the right pump is crucial to ensuring an equal amount of nutrient solution is delivered to each dripper.
Drip irrigation systems are generally called either ‘low pressure’ or ‘high pressure’, referring to the size of the pump used and dripper type
Most small systems with up to 16 drippers can operate on small low-pressure pumps such as the Maxijet 1000.
If you’re going above this number of drippers, then you’re better off running a high-pressure pump such as the Aquaking range of pumps.
And for very large high-pressure drip systems, we also stock the Hailea L Series Pump, with a massive 12,000 litre per-hour flow rate and suitable for huge multi-plant drip systems.
In fact, there is a way to use this method for every growing media.
Drip irrigation can be used on a single plant or many - the options are endless.
6. Ensure no syphoning occurs
If you’re using a low-level tank under your pots, such as with the Wilma system, this won't be an issue.
But if you are using a larger external reservoir such, as a water butt or flexitank, you need to incorporate an anti-siphon option.
This can be in the form of an anti-siphon valve, such as the ones included in our Critical Drip Systems. Or simply a small hole in the pipe from the pump inside the reservoir/tank above the water level.
This will squirt out a small amount of solution when the pump is running. And when the pump turns off, it sucks into the system and breaks the siphoning action.
Without an anti-siphon option, your reservoir will continue to empty when the pump turns off and empty your reservoir down to the same level as your drippers.
It’s an easy mistake to make - don’t get caught out!
Finally, let’s take a look at some essential drip system extras that can help make all the difference to the yield and quality of your plants.
- Suitable timer. For drip irrigation, you need an accurate timer for your pump that can be set down to minutes, sometimes even seconds. We have a range of options available, from the highly recommended IWS dripper timer down to the more budget option 24hr digital timer.
- Cleaning agent: We recommend using a cleaning agent in your nutrient solution to help prevent build up inside your dripper pipes which can lead to blockages. ATA Clean is ideal for this and can be used with any nutrient or additives. Silver Bullet Roots is also suitable when not using any beneficial bacteria products or organics.
Thanks for reading our guide to drip irrigation systems. As you can see, getting your feeding times and nutrient levels right can easily be achieved with the right equipment and planning.
Or drop by our Sheffield store. We'll be more than happy to get into the real nitty-gritty of drip irrigation with you!