Drip Irrigation

This issue we put the spotlight on a method that is simple to set up and produces results so good that it is utilised in commercial growing applications across the globe, from producing quality tomatoes for the biggest UK supermarkets to producing top quality smoke for the coffee shops of Amsterdam. Our quest for quicker crop cycles and heavier yields continues; this issue, we take a closer look at the drip irrigation...

This issue we put the spotlight on a method that is simple to set up and produces results so good that it is utilised in commercial growing applications across the globe, from producing quality tomatoes for the biggest UK supermarkets to producing top quality smoke for the coffee shops of Amsterdam. Our quest for quicker crop cycles and heavier yields continues; this issue, we take a closer look at the drip irrigation...

Think of drip irrigation and what springs to mind? Probably large scale greenhouse cultivation; acres and acres of tomatoes or cucumber plants, grown on rockwool slabs with miles of dripper line connected to computers that control complex feeding schedules. A little too complicated for the home grower, right? Wrong! Drip irrigation is one of the simplest and most flexible hydro methods on the market and it is available on any scale, from one plant upwards!

Drip irrigation systems for the home grower offer the quicker growth cycles and bigger yields of active hydro, with the flexibility to grow in any medium - soil, coco, rockwool or clay - and even grow in pots.

So, how does drip irrigation work? Let's start at the beginning...

What is drip irrigation?

There are many types of drip irrigation, but they all work on the same principle. Your plants are started in a growing medium and a dripper is placed into, or suspended over, the medium. The dripper is attached to a dripper line, which is in turn attached to a pump.

You keep your nutrient solution in a reservoir and, at periods set on a timer, nutrient solution is pumped from the reservoir, through the dripper line and delivered to plant via the dripper.

The nutrient solution works its way through the medium and over the roots of your plants, draining out through the growing medium and drawing oxygen into the root zone. Feeding small doses of water and nutrient at frequent periods throughout the day, means that the growing medium will not get totally saturated and there will always be plenty of oxygen present around the roots of the plant. This ensures healthy development and faster growth.

As plants mature, the number of feed periods is increased. The amount of nutrient solution used by the plant is easily measured and this allows you to tailor the number of feeds to achieve the optimum growth and yields.

Drip irrigation offers something for every grower, from the soil lover who just wants to keep their pots automatically watered, to the hydro expert who is looking to measure the nutrient uptake of their crop on a daily basis and devise the perfect feeding schedule for their own growing environment.

One is for sure, if it is the preferred method for the commercial growers, then it is certainly worth giving it a try! Read on...

Why drip irrigation over hand watering pots?

• Plants grow faster and yield more - plants take up more water and nutrients than they would with hand watering, feeding little and often throughout the day is healthier than giving one large feed every other day
• Gets nutrients where they need to be - in a drip irrigation system you aren't relying on capillary action to deliver water and nutrients to the plants roots. Instead, drippers feed the roots from above and gravity pulls the nutrient solution down. Feeding techniques that rely on capillary action make the medium at the bottom of the pot wetter than anywhere else, which can stunt root development and slow plant growth.
• Reduced chance over or under-watering - when plants are fed little and often, the medium is never saturated or starved of nutrient solution. Hand watering plants once every few days can result in water-logging because the plants can't take up all the solution given to them in one go.
• Less work - drip irrigation systems are low maintenance. Manage one nutrient solution tank for all of your plants and top up every couple of days - far easier than hand watering.

Types of drip irrigation system

There are many types of drip system available to the home grower, they fall under two main categories;

•  Recirculating systems
In recirculation drip irrigation, the plants usually sit above the nutrient reservoir. Whatever solution the plants do not use runs through the growing medium and back into the reservoir, ready to be pumped back to the plants again. The benefit of these systems is that they are simple to operate and set up and, because all the workings sit above the nutrient reservoir, they are virtually leak proof. There are three main types of recirculating systems...

• Single drip ring systems
In a single drip ring system, plants sit in a planter, usually filled with clay pebbles, placed above a nutrient solution reservoir.

Feeding schedules are set on a timer and solution is automatically pumped from the reservoir and out of the drip ring directly onto the root zone. Plants receive all the nutrients and water they need as well as superb oxygen access; because every time the system drains, oxygen is pulled down into the root zone.

When used with clay pebbles, drip ring systems provide a healthy, oxygen-rich root zone, thanks to the free draining nature of the medium. The ideal environment for keeping a mother plant long term or just taking one big plant to flower and achieving the maximum amount of buds! Some of the yield results achievable using these systems have to be seen to be believed!

Popular versions of these systems available in the UK are the AquaFarm, WaterFarm and the Flo-Gro.

• Pot Dripper System
In a pot dripper system, pots are placed on a tray above a reservoir. Plants and drippers are placed in the pots along with your chosen growing medium. The feeding frequency is set with a timer, whereby the nutrient solution is pumped from the reservoir to the drippers, and over the roots.

The nutrient solution works its way through the medium and over the roots of your plants. Whatever the plants don't take up, drains through the holes in the tank, ready to be pumped through the drippers again.

Pot dripper systems are perfect for beginners or growers who want to make that first step to hydro because they can be used with any growing medium and offer the familiarity of using pots.

Popular pot dripper systems available in the UK include the Wilma system - which is available in a wide range of sizes and pot variations - and, more recently, modular pot dripper systems that allow you to space plants under lights however you like - so they can grow huge!

• The Dutch Dripper System
Very similar to the pot system in that the plants sit on a tray above the reservoir, but the Dutch Dripper system uses slabs - either rockwool or coir - rather than pots.

• Run to waste systems
In a run to waste system, nutrient solution is pumped from a reservoir to the plants using lines and drippers, but rather than draining back into the nutrient reservoir, the solution runs out of the growing medium and into a waste tank or drain, it is not reused. Run to waste systems tend to be used in commercial scale cultivation, the main benefit being that the nutrient solution is always fresh and contains the optimum balance of elements.

Many large scale cannabis growers use run to waste systems as they are very simple to set up, reduce the watering workload and produce great results. Plants can be grown in pots filled with growing media or in rockwool or coir slabs.

One major benefit of run to waste dripper systems is that they are so easy to expand. Extra lines and drippers can be added to the system easily.

Just make sure that the solution run off is contained properly. A full hundred litres of nutrient solution leaking out of your system is likely to bring some unwanted attention to your grow!

What type of grower is drip irrigation good for?

As drip irrigation is such a flexible method and there are so many styles of system available, there is something for every grower;
• New growers who want an easy to use system so that they can concentrate on maintaining their growing environment should try a pot dripper system.
• Experienced growers looking for a hydro system that allows them to monitor nutrient uptake and set an optimum feeding schedule to maximise yield should try a pot dripper system with a hydro medium like clay pebbles or try a Dutch Dripper system.
• Personal growers could grow one big plant full cycle in a drip ring system or get the most from a small number of plants in a 1.2 metre tent with a pot dripper system.
• Large scale growers should look to a custom built run to waste system where they can spread their plants out in a large area and feed them from one reservoir.

The Three Steps To Drip Irrigation Heaven!

1. Use the correct dripper for the growing medium. Drippers are available in a wide range of sizes and flow rates. If you are growing in a free draining medium like clay, use an unrestricted dripper. This will allow the nutrient solution to flow over the roots as quickly as the pump will allow and will pull lots of oxygen into the root zone as it drains through the medium. If you are using an absorbent medium like soil, coco or rockwool use a dripper that restricts the flow rate otherwise the growing medium will become saturated. A 2 litre per hour dripper set on a 15 minute feed will deliver half a litre of nutrient solution to the plant. Ideal for most plants.
2. Increase the number of flood periods as your plants mature and increase in size. This will ensure you get the maximum growth and the biggest yields. When using clay pebbles, set the timer to two 15 minute flood periods per day for young plants. As plants grow, you can increase to a maximum of one 15 minute feed per hour. You will need to perform a complete solution change every 1-2 weeks. When growing in an absorbent medium set the timer to just one 15 minute flood period per day for young plants. As they grow, increase to a maximum of four 15 minute feeds per day. When using an absorbent growing medium you should run the system to minimise run off and perform a complete nutrient solution change every 2 weeks or sooner if the level of solution is running low.
3. Use an anti blocking agent. Dripper line has a small internal diameter and over the course of a full grow - 8 to 14 weeks, depending on strain - there is the potential for these dripper lines to become blocked, particularly if you use concentrated, mineral nutrients and stimulators (and if you want the biggest amount of bud possible, you will be!). Adding an anti blocking agent to your reservoir will keep things flowing freely.

Quick Q&A with a Pot Dripper Grower

When can plants be transferred to the system?
Just as soon as they are root bound in their starter medium, you should see white roots on the outside of the block or pot.

How should plants be spaced?
In a pot system the spacing is already decided, you can get them with the pots closely spaced for a sea of green or spaced far apart if you want to grow some trees!

Will plants need to be supported?
Not in a pot dripper system because there is plenty of media around the roots, but if you are using drippers and slabs then you will need to use some kind of plant support.

So, there you have it; commercial growing techniques are available to the home grower. If you are looking for a simple set up and big yields... get dripping!