Drip systems – our guide to growing with drip irrigation
There are many methods of growing that can be used very effectively to grow your plants, hand watering, pure hydroponics, bottom fed systems, NFT, deep water culture, aeroponics, flood and drain etc - We have used all of them and all have many benefits, but most of all we love a good drip system. Timed irrigation tailored perfectly to provide the right amount and strength of nutrient every time directly to your plants root zone. Probably the most versatile system going they can be used for most growing methods from organic growing to pure hydroponic drip systems - there is a way to use this method for every growing media. Drip irrigation can be used on a single plant or many, many plants the options are endless.
What is drip irrigation?
Drip irrigation is providing nutrient directly to the top of your growing media usually via a timed irrigation pump, automatically feeding as needed. It can be set up as a run to waste system or recirculating as required by plant demands and type of media being used.
Why do I need a drip system?
Drip systems allow for precise control of nutrient levels within your plants rootzone, you can measure run off levels and fine tune your feed and irrigation times to suit your plants size and stage of growth. Doing this is the best way to achieve healthy, fast growth and great yields. 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, so you have more time to spend on other jobs around the grow room – or to simply chill out a bit more!
When you are experienced in using a drip system and have it fully dialled in you can even go away for a few days safe in the knowledge your plants are still getting everything they need while you’re not there.
What types of drip irrigation are there?
Drip irrigation can generally be split into 2 main types – Run-To-Waste and Re-circulating systems.
Run-To-Waste – These systems, as the name suggests, allow the run off to be collected and disposed of rather than running back to the main reservoir, it can be a simple as raising pots above a container and emptying the container as necessary or more elaborate involving 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 to running a multi-plant system or large set up. This is our preferred drip irrigation method as every time the plant is fed it is fresh perfect nutrient solution and the run-off helps stop build-up of any excess nutrient within the root zone. Its almost like a conveyor belt of nutrients going past the plants roots that they can use what they need at that time, rather than being fed the same solution over and over again which they may have already depleted the nutrients they need at that stage. You obviously need to dispose of the ‘waste’ nutrient and some people find this method too wasteful, but with the right media and careful feed times the waste can be minimal and can also be used around the garden or greenhouse for feeding other plants, lawns etc.
Recirculating – These drip systems ‘recirculate’ the nutrient solution so all the run-off returns back to the same tank it is fed from such systems include the Wilma 4 pot system and Wilma 8 pot system where the pots sit above the low level nutrient reservoir and the nutrient solution is pumped up into the top of the pots and runs out down to 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. They are particularly suited to using a free draining media such as clay pebbles where using a run to waste system is totally impractical as you would waste way too much nutrient 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 pipe work for the pump and nutrients, using the bottom tray/tank to only collect the run-off from the pots and empty as necessary.
What is the best drip irrigation system?
This is down to a lot of factors including personal choice, as an all rounder the modular nature of our Critical Drip System allows for use in any size and shape of room its low level so you don’t lose head room and can be run as recirculating or as we prefer as a run-to-waste system. It's available as a 'lite' system for 4-8 plants or as a high pressure system from 12 to 48 plants. For smaller set ups such as an XL or XXL tent the Wilma 4 pot system and Wilma 8 pot system are an excellent choice also. Some of the best drip systems are home-made and can often outperform expensive off the shelf options, they are bespoke to your room size and layout, can be tailored to suit your needs better and are normally cheaper. We love helping people design and build custom drip systems and are more than happy to help you get the best from your own drip system whatever your budget.
How long do I run a drip system for?
There are many variables that affect this including substrate choice, pot/container size, plant size and stage of growth etc. As a general rule your irrigation duration can be determined by turning your pump on when your plants are due a feed (pots/container getting lighter but not fully dry) and timing how long it takes for run-off to occur out of the bottom of the pot. This is how long your pump should be on for and will increase as your plants get larger. The frequency of your feeds (how often your pump is on) depends massively on the media being used and pot size but should be the time it takes for the pot to get to the same moisture levels (weight) it was before the last feed occurred. In free draining substrates such as clay pebbles or rockwool cubes then irrigation frequencies can be as often as every hour or two when plants are feeding heavily, whilst in larger pots with substrates such as coco and indeed soil they are often only watered only once or twice a day, up to 2-4 times a day for smaller pots of coco. Indeed 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 in large pots only irrigate every few days and will just turn the drip system on manually when a feed is required.
Golden rules of drip irrigation!
1 - Only irrigate when your plants are awake! – ‘Transpiration before irrigation’ - your first feed should be an hour after the lights have turned on allowing your plants to wake up start transpiring and start using any nutrient left in the pot before you feed it anything else. It takes a while to get going in the morning sometimes and your plants are just the same this allows the processes within the plant to start happening and nutrient demand to begin before you start feeding. Time your last irrigation (if using multiple feeds) for at least an hour or two before lights out so that the nutrient and water provided is mostly used before the plants shut down for the night period. Irrigating right up to the night cycle can lead to your plants being over-wet through the night and still wet in the morning which can lead to overwatering issues and sluggish growth rates.
2 - Establish plants before drip feeding – In some growing media such as coco and soil it is essential to establish plants in the pots and allow a good root system to develop before feeding via the drippers, the best way to do this is to hand water coco or soil plants for a week or 2 after potting up to allow for precise control of individual pots while the plants establish (when using some free draining media such as rockwool or clay pebbles this is either not necessary or not necessary for as long).
3 – Measure run-off volume – you are aiming for around 10-20% run off with most media this ensures your plants have everything they need and any unused nutrient in the pot is flushed out. Too little run off and your plants may not have enough water/nutrients, too much run off and you may be overwatering your plants which as mentioned can slow growth and damage your roots – also wasting nutrients. You can measure this in 2 main ways, either measure the volume of run-off in relation to the amount that 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 if you have a 100l reservoir and have used roughly half of it (50l) then you want roughly 5-10l of run off in your waste tank or if you’ve used the full 100l of nutrient then you want 10-20 liters run off in your tank. If you have too much, then cut either the frequency or duration of your feed times. If you have too little increase as needed.
Measuring run off by time - this method can be a little trickier and does depend somewhat on the media and pot size being used. You need to measure how long it takes for run-off to occur when your pump comes on and are aiming for 10-20% again so if you are giving your plants a 5 minute feed for example, that’s 300 seconds of feeding, you want run off after 80-90% of the feed time has elapsed so you want run off to occur after the pump has been on for 240-270 seconds (4 to 4 and a half minutes). This method is harder to judge when using multiple feeds throughout the day as often the first feed of the day will not get much run off if any while the later feeds will produce more -in this situation measuring your run-off by volume is more suitable.
4 – Measure run-off nutrient levels (EC) and pH –This is one of the main advantages of using a run-to-waste drip system over other methods, when using a hydroponic substrate or coco you can measure your EC and pH levels and fine tune your feed levels accordingly to the perfect level for your plants current requirements.
EC levels – ideally you want you run off EC levels to be the same or slightly higher than your input EC levels, this ensures your plants have everything they need and a little more. For example your in early to mid-flower and your plants demands are at their highest you are feeding an EC of 1.6-1.8 so you want you run-off EC levels to be 1.8-2.0/2.2 If your EC levels are coming out lower than your input EC levels then you know you can add more feed and push your plants a little harder and achieve a better yield (If you need to raise your EC a lot do it slowly in increments over the course of a few days to a week, a big increase all at once can be detrimental). On the other hand, if your EC levels start creeping up and are coming out a lot higher than your input EC levels then you know you need to back off on the levels to prevent overfeeding. Regularly measuring your run-off levels and reacting accordingly if they spike can save you plants from overfeeding issues and prevent a lot of problems before they occur – ultimate control!
pH levels – Similarly to EC levels you can measure your pH levels and react accordingly with the pH level of your input feed. pH levels will change within your rootzone and indeed we want a swing of pH levels as different nutrients are more available at varying pH levels. Ideally a pH range of around 5.8-6.2 is desirable. Knowing this you can measure your pH levels in your run-off and if they start coming out a little high then you can drop your pH levels of your input nutrient. For hydro and coco drip systems you should never drop your pH below 5.5 ideally.
Note – these levels being right is dependent on getting the right amount of run-off always check your run-off volume too as if there is not enough run off simply increasing this can rectify pH or EC levels within the root zone.
5 – Choose the right pump – This is crucial to ensure 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 pump used and dripper type etc. Most small system with up to 16 drippers or so can operate on a small low-pressure pump such as the Maxijet 1000. Above this many drippers and you are better off running a high-pressure pump such as the Aquaking range of pumps which can cope with up many drippers. 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 suitable for huge multi plant drip systems.
6 – Ensure no siphoning occurs – If you are using a low level tank under your pots such as with the Wilma system this isn’t an issue but if you are using a larger external reservoir such as a water butt or flexi-tank you need to incorporate an anti siphon option, this can be in the form of an anti-siphon valve such as is included in our Critical Drip Systems or simply a small hole in the pipe from the pump inside the reservoir/tank but above the water level, this will squirt out a small amount of solution when the pump is running but when the pump turns off it will allow air to be sucked into the system and break 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 – don’t get caught out!
Essential drip system extras -
Suitable timer – For drip irrigation you need a timer for your pump that can be set down to at least minutes, sometimes seconds, we have a range of options to suit 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.
We hope you have enjoyed this brief guide to drip irrigation systems it gets a lot more in depth and complicated than this but we have tried to keep it simple and easy to digest for now. For more in-depth drip system advice including full system design, construction and maintenance feel free to get in touch via phone, email or the usual social media channels, or drop by our Sheffield store and we will be more than happy to get into the real nitty-gritty of drip irrigation with you!