Fertigation Brings Precision To Cannabis Nutrient Application

DEMAND SPELLS FREEDOM

The existence and need for fertigation systems in the cannabis industry are an indication of the popularity of cannabis where it is legal. Such high-tech systems increase productivity, efficiency, and product consistency on a large scale. As legalization continues to be adopted around the world and prices drop, automation is the solution to staying competitive while producing quality product.

WHAT IS FERTIGATION?

Fertigation (a term combining fertilisation and irrigation) is a highly accurate automated nutrient application system, generally for large-scale cannabis operations. Fertigation systems use dissolved nutrients, which eliminates the need for time-consuming mixing by hand. This allows for the cultivator to spend more time on the plants themselves. It is also adaptable for small-scale growers who don’t have a lot of time to measure nutrients or hand-water.

Borrowed from the mainstream horticulture industry and customised for the idiosyncrasies of cannabis growth, fertigation delivers already dissolved nutrients in the desired formulation straight into the irrigation system. This has advantages over enriched planting mixes or dry fertiliser, whether they are used to amend the medium or as slow-release nutrition. They both remain in the grow medium until they are used up by the plant, even when a different formula is required to compensate for environmental fluctuations or a different phase of growth.

RESPONSE FLEXIBILITY

Fluctuating environmental conditions means plants use nutrients in different ways. In a greenhouse environment where temperatures can rise and fall, and available light can vary in intensity, plants will need more nitrogen to keep growing fast when temperatures are cooler and light is low. At the other end of the scale, nitrogen enrichment under intense light and high temperatures causes plants to stretch. Fertigation allows for complete customisation of dissolved nutrients, which maximises plant growth at all times.

EASY TO RETROFIT

Fertigation can be incorporated into your preferred existing watering system. Drip lines, flood and drain, capillary mats, flood tables, and even wicking—each can benefit from the precise nutrient delivery that fertigation offers. Fully water-soluble nutrients are preferred as a means of keeping lines clean; however, as long as the system is well-filtered and flushed regularly, organics like compost teas and insoluble additives can be used.

EASY TRANSITIONS FOR OPTIMAL GROWTH

The difference in nutrient demands between vegetation and flowering can be quite drastic. Fertigation makes the transition from one type of solution to another simple. Whereas time-release fertilisers and organic additives can only be partially flushed away—as some insoluble salts remain in the medium—fertigation allows for a completely clean rinse as the nutrients are already dissolved in water. Once flushed, simply begin feeding the new mix. This eliminates the need to compensate for any undissolved salts that may throw the EC off.

EFFICIENT GROW MEDIA

Fertigation is similar to hydroponics in that nutrients are delivered via the water. The difference is that hydroponic systems use inert substrates like rockwool, vermiculite, and perlite, whereas fertigation systems use organic substrates, such as coconut coir mixes.

Organic grow media contain a high concentration of carbon compounds, which act as a buffer. These compounds lightly bind with nutrients and slowly release them as the medium becomes more diluted. Buffering makes it easier to maintain the best conditions for cannabis growth, without the precision required in pure hydroponic setups. The carbon matrix also allows for a healthy rhizosphere to develop, where microflora interact directly with the root system, promoting nutrient uptake and overall root health.

SMOOTH OPERATION

There are a few things that need particular attention when using a fertigation system. Inline filters in the irrigation system, placed immediately after the injectors, must be included. Organics and compost teas may contain fine particles that can clog distribution methods like drip lines. A regular flushing of the system at the end of every cycle is recommended to keep lines free from buildup. Other systems with bigger nominal diameter (ND) piping are less susceptible to blockages.

However, in larger grows, plants at the head of the system could be flushed free of nutrients by the time the drippers at the tail of the system have been cleared. As a prevention, extensive grows are broken into parallel intermediate systems fed separately from their own primary water manifold. Or, each intermediate system is flushed separately, using a common mainline, to maintain water pressure. A backflow prevention device is used immediately before the injectors to stop any source contamination.

THE SPREAD OF AUTOMATION

Fertigation can certainly constitute an added cost when designing an irrigation system for cannabis, but the costs are quickly recouped. The low overhead of running a system soon pays itself back. Quality and growth consistency are maintained over a whole crop with less likelihood for human error, manpower can be more efficiently distributed, and scheduling can be tighter.

Increasing sophistication in automation has lights, fans, irrigation, nutrient mixing, and environmental parameters all monitored and controlled automatically. Fertigation brings the domestic and commercial, scalable, plug-and-play marijuana growing machine just one step closer.