Stronga are working with numerous growers in various niche sectors within horticulture. In the example case study here, we are discussing a leading cut flower grower through which we have had the pleasure of supporting on their journey to a low waste world.
Current growing practices often involve single-use and then disposal of horticultural growing media which is extremely wasteful in several ways, including the clear waste of growing media that has the potential for remediation.
There is further cost and carbon use in the form of road fuel used in the routes to growing media acquisition and disposal which are often overlooked.
Within the last few decades, horticultural growing businesses have moved to crop production using a controllable, blended growing media. The use of locally-derived soils has decreased due to the difficulty in being able to manipulate it sufficiently to produce the optimal conditions for the crop.
With increased scientific understanding of crop responses to growing media structure and blends, it is possible to greatly improve the level of growth control that can be achieved.
The use of growing media has been necessary in the production of many ornamental plants produced in containers. However, as with soil grown crops, crops grown in other mediums are still susceptible to pests, diseases and weeds.
A wide range of pesticides used on crops in the past are increasingly banned with plans from many governments to enforce reduced pesticide use in the coming years. In some cases this blended growing media has been seen in the past as having limited use and has been discarded at the end of a single crop growing period which can be as short as a few weeks.
When this media is discarded, in often still contains some of the pesticides applied to it and much of the nutrient value is still contained within it. Use and disposal methods for growing media used in commercial horticulture has become a significant issue and the potential threats from pesticide residues horticultural crops have become more prevalent.
Steam is the cleanest method of media sterilisation, using nothing but steam to deeply penetrate and sterilise growing media. Stronga have an elegant, simple and cost effective soil remediation solution in the form of FlowSteama and SteamBoila.
See below the steam sterilisation process carried out by our leading North American flower growing client.
In this example, cut flowers are grown in trays from bulbs in a semi-automatic planting system. After each crop, our clients used FlowSteama to effectively sterilise the growing media for immediate re-use in a short cycle circular method, offering many advantages…
After the growing phase, the trays (including the media, root and some trash) are unloaded onto a conveyor where a shedder / chopper unit breaks up the material into a more homogenous blend.
The images below show the hopper loading conveyer with material containing roots and plant material. The conveyor delivers the media blend, complete with roots and trash, into the FlowSteama hopper.
Material, once processed through FlowSteama, is clean and can be re-used immediately. The image below shows the sterilised growing media going straight back into trays for planting the next crop.
Peat is the main substrate used by the horticultural industry in many counties. It is a blend of plant material which has undergone a partial, slow, anaerobic decomposition. However, increasingly there are calls for peat use to be reduced.
Organic matter content, air filled porosity and water holding capacity is high in peat material. It is extremely useful; best for growing media and FlowSteama now empowers the grower to reduce peat use while keeping all the benefits using steam to clean the contaminated media.
Peat is mostly used by the amateur (hobby) market with only about one third by the professional grower; this of course varies by market and country. End users and wholesale clients are demanding growers reduce their peat use and carbon footprint. Stronga FlowSteama and SteamBoila offer a direct and fast win – win solution.
Local bark is a renewable indigenous resource which is widely used in horticultural crop production, particularly in the nursery industry. When used in peat mixes, bark increases the air filled porosity and also has good nutrient holding capacity. There can be problems obtaining the substrate in large, uniform quantities.
Pine bark has the added advantage of suppressing pathogen populations within the compost / media mix. There are some disadvantages related to bark use including high manganese and chloride levels. Some barks can also immobilise nitrogen, requiring extra nitrogen to be added which is costly and an energy use issue.
The FlowSteama process reduces the need for growers to resort to bark, allowing them to recycle a high quality growing media with all the advantages that offers.
Coir is a renewable product but non-indigenous to many growing areas as it is a waste product of the coconut industry. Batches are often of inconsistent quality due to the varying countries of origin.
On the positive side, coir is a stable, lightweight medium with good air filled porosity. It can be used in blends with other peat alternatives such as bark / shredded biomass or composted green waste. Coir is well-proven as a peat alternative, especially for protected crops like bedding plants.
As for all peat alternatives, coir requires different irrigation and nutritional management. It has proven to be superior to peat in some crops. Coir gives excellent rooting due to its high air capacity. It has a low nutrient status and relatively uniform texture.
Some of the disadvantages are the high initial potassium content which can reduce magnesium availability, resulting in yellowing foliage. Nitrogen lock-up can also occur as the coir decomposes in use which can necessitate treatment with calcium nitrate to reduce the lock up of Nitrogen; this of course adds to the cost. These issues are avoided using Stronga FlowSteama which recycles material.
Many growers are turning to shredded woody biomass to develop a more local renewable media blend which is generally available in large quantities from local authorities or private manufacturers. Depending on some factors, this shred can have high nutrient levels, particularly potassium.
High pH can be an issue which has to be diluted with low-nutrient material such as peat or coir before use as a growing medium.
Wood waste and primary wood fibre residues in growing media increasing find competition from biomass fuel heat and animal bedding uses which could increase your costs. FlowSteama gives you the potential to recycle your media and save with every re-use of the soil.
Some composted green waste has high chloride and conductivity levels which are damaging to plant roots. Composted green waste can be used in growing media, typically as 15-60% of the mix, combined with a low nutrient material to dilute the high nutrient levels.
FlowSteama offers benefits by simply:
Traditionally, loam had high organic matter content; loam today tends to be just topsoil with low organic content. The majority of topsoil harvested is used in landscaping and for amenity use; not in growing media. Loam or topsoil from green-field sites is becoming increasingly difficult to source; most is surplus soil coming from construction operations.
Loam is useful as a component of a growing medium to increase water holding and nutrient buffering capacity, but only often below 15% of the mix due to its high bulk density. Specific products such as clay minerals derived from soil are also used at a low % to increase the chemical buffering of a mix. Loam needs to be pasteurised to kill pathogens and weeds; this can be done efficiently with FlowSteama and SteamBoila.
Perlite is derived from volcanic rock, crushed and heated, forming a white porous mineral material. It is inert and sterile on first use and is used widely as a propagation material. It can also be added to composts to improve the air - water balance.
FlowSteama and SteamBoila offer a continuous steam sterilisation system, allowing quick growing media output to keep your soil substrate working.
Composting of roots and organics is sped up which offers advantages, especially if you blend the organics before sterilising to create high quality, nutrient-rich growing media. The FlowSteama continuous moving floor allows for your business to sterilise large amounts of soil and potting mix in a non-labour intensive system.
Using FlowSteama and SteamBoila, clients can completely recycle their media. See below a general overview of the benefits:
Saving resources and the planet; Significantly reducing growing costs every year; Reducing waste and pesticide contamination issues; Saving the environment in many ways; less trucks transporting growing media.
Lower production cost; Better quality, sterilised media; Better quality, faster growing plants; Lower disease in the plants – less wasted crop.
Avoid disposal costs; Meet climate and carbon targets from wholesalers; Use the nutrients already present in the media you own.
Stockpile of existing media often from years of production can be sterilised and sold for cash.
Before FlowSteama, growers used to be forced to purchase new growing media for every crop, or grow using the same media multiple times. They would suffer increased disease risk which lowers growing performance and increased losses of crop due to contaminated soil.