Simplification the key to success
Greenhouse growing can be very profitable if managed properly.
In good conditions crops grown in greenhouses will yield 10 to 20 times more each year than a similar outdoor crop. Typical greenhouse crops include tomatoes, capsicums, chilies, cucumbers, eggplants, lettuces, witloof, courgettes, sprouted beans and other herbs/microgreens.
Many growers raise their crops hydroponically, using different ways of trickling nutrient solutions through the soil-less growing medium. It’s a high-precision growing system which is capital intensive because of the high cost of basic equipment. It needs high energy, fertiliser and labour inputs but is very profitable if managed properly.
In order to maximise profitability of such systems, there are three things to concentrate on;
• Minimising investment costs and resource inputs
• Maximising resource use efficiency, yield and crop quality
• Automating as much as possible and making everything simple and cost effective.
Even though it’s mentioned last simplicity is always an over-arching goal and is not necessarily the opposite of high precision. Sure, high-tech can be advanced, but the operating principles and its use can be very simple as the less that needs to be done to achieve a goal the better. In greenhouse crop production demand-driven fertilization reaches peak performance.
Growers want to control all the major parameters independently, even though they’re striving for simplicity in each. So, for example, irrigation and nutrient supply should be controlled as two separate and easily adjustable inputs, even though they’re applied together as one nutrient solution.
Minimising investment costs Investment costs can be lowered by making the system as simple as possible, but this can be tricky, as many factors are in play at the same time.
One good example is the fertigation technique. For instance, if the system is hydroponic, irrigation and fertilisation is often driven by a re-circulating nutrient solution adjusted according to certain specifications. Many growers have a system where they adjust each plant’s nutrients from a tank for each nutrient. It offers a lot of control, but is very complex and a lot can go wrong. This necessitates rigorous monitoring of the fertigation programme, and often many adjustments through the season at different stages.
Skilled growers can often use their own experience-based gut-feeling with good results, but the complexity and risk remain the same. This could be simplified with a demand-driven approach because if nutrients are matched to the plant’s growth rate, in an ideal composition (see table), there’s no need for different tanks for different plant nutrients. One complete fertiliser product can be supplied which simplifies management of the recirculating solution itself, by lowering the accumulation of some nutrients.
So look for ways to simplify production.
It’s also important to understand the cost-benefit ratio of the investment, as seen in its return on investment (ROI).
Minimise resource inputs
With water, fertiliser, heating, light, energy and plant protection the main aim is to minimise losses.
Energy is a big factor for the light supply, whether it’s boosting natural light or is the sole source. LEDs are a huge advancement, and it pays to be aware of any new products.
With fertilisers all the applied nutrients should end up in the plant, without any losses such as having to dispose of left over recirculation solution, drainage or leaching or nutrients bound up in the growing media. Any excess consumption of nutrients is another form of loss and again, a demanddriven approach is the best way to achieve this.
Maximise resource use efficiency
It’s important to fully utilise whatever is
added to the system. With fertilisation it’s not only about avoiding excess application, it’s about knowing how to fully use each nutrient. If nutrients are supplied in ideal ratios constantly throughout the season they’ll always function in synergy, no deficiency will occur, and each will constantly be used for maximum plant growth and development. So question what you want to achieve and what’s needed to do that.
If the system is balanced to grow more with less and investment in the system is streamlined for maximum production, maximum yield will follow as a result. Don’t be afraid of investing in worthwhile equipment and resources, as the cost-benefit ratio often is worth it. Differentiate between optimal and maximum yield as sometimes theoretically a higher yield can only be obtained at a cost that’s not worthwhile.
Maximise crop quality
In theory this is a yield trade-off as resources absorbed by the crop are used to create quality-enhancing substrates such as sugars and antioxidants and are even allocated to the fruit. Quality comes naturally if the resources needed are supplied in a balanced way throughout the season and if optimal yield is the target.
Automate as much as possible
This comes with a trade-off that more monitoring may be required and her again the key word is simplicity.
Make everything simple and cost effective
Reduced complexity is always a bonus. It often means less risk, less labour and a more forgiving system if mistakes are made. If fertigation can be managed by a simple computer programme that doesn’t need constant adjustments that’s worthwhile. So is a medium which automatically drains if there’s accidental over-irrigation. Anything that reduces monitoring and micro-tasks is the goal.
▴ If fertiliser is supplied frequently to match the demand of the crop through the season, optimal growth is sustained, preventing losses, lowering total fertiliser inputs and costs.
▴ Optimal nutrient status enables maximum growth and so the greatest use of each nutrient.