The German and international horticultural sector, as well as the substrate industry that supplies it with growing media for the purpose of plant production, has to deal with the problem of decreasing extraction quantities of German black peat, which will become increasingly acute in the coming years. On the one hand, the resource is finite; on the other hand, no new peat deposits will be released for extraction. In addition to the natural shortage of black peat, a significant reduction in the amount of peat used in the coming years is politically desired. This will lead to the increased use of alternative substrate materials in all areas of horticulture and more than is already the case today.
Without a high percentage of suitable black peat in the growing medium, the durability of these machine-produced press pots is currently not assured. The average proportion of black peat is 80-90% by volume, but press pots are also often made from 100% black peat. The lower the proportion of black peat, the lower the durability of the compressed pot. Other proportions can be the less decomposed white peat, but also increasingly alternative substrate constituents such as green compost or fine wood fibres.
Young plant nurseries that specialise in the production of press pots and propagation in press pots sow various types of vegetables, herbs and occasionally ornamental plants. In vegetable production, the durability of the press pots is of decisive importance, as these are planted out with special planting machines, e.g. outdoors but also in greenhouse cultivation, after the seed has germinated and the root development is sufficiently advanced. The mechanical stress on the press pots is quite high and they must not break apart!
In order to be able to provide the highly specialised seedling nurseries with growing media for the production of press pots even in the event that, due to the scarcity of black peat, there is an increase in the use of white peat and other common raw materials in horticulture, or in the event that press pots have to be produced, which meet the requirements of national and international organic associations (high proportions of alternative substrate constituents are then required), a substrate additive is needed which allows the young plant grower and the further processing horticulture to deviate as little as possible, or not at all, from their usual production methods. This additive must fulfil a large number of properties and conditions in order to be suitable for this purpose.
After long research, intensive development work and extensive test series, Floragard has succeeded in developing such a substrate additive – Flora Eco-Glue. According to practical results of the last 2 years, it should be possible to reliably produce and process press pots with white peat contents of 50 % by volume and higher or with a high proportion of alternative substrate constituents. At least this is the current state of numerous trials of highly specialised seedling nurseries in Germany and abroad with substrates from German and Baltic substrate factories.
In this context, press pots were created in 2 companies even from substrates with a proportion of 70 % by volume of white peat, which met the requirements for further processing.
Due to its suitability for organic growing, a substrate containing 35 % alternative substrate constituents was also tested in a company that produced seedlings in press pots in compliance with the criteria for organic growing. Neither serious changes in crop management nor significant technical changes to the press-pot machines had to be made by the grower. Only the amount of water used in the production of the press pots had to be increased by up to 20 percent. However, this does not result in free water or water that sludges the press pots. The growth of the young plants was completely normal in all internal and external trials carried out so far and comparable to the growth in conventional substrates for compressed pots. In some cases there was even improved root growth, which is certainly due to the higher air supply in the substrate. Also the root growth from one press pot into the neighbouring press pot, which is undesirable for the grower, does not take place more strongly with the use of Flora Eco-Glue than with conventional recipes for compressed pots. The additive has no effect on the handling and storage of the substrates, is suitable for organic growing and therefore suitable as an additive for crop production according to ecological criteria.
In order to make a future application more economically interesting than would be the case at present with an application of Flora Eco-Glue, Floragard is currently carrying out further trials to optimise the application rate and/or effectiveness in combination with already known substrate additives.
One thing is certain – the German black peat will soon run out and more and more white peat or alternative substrate constituents will have to be used. Companies producing press pots, which have invested millions in production processes based on substrates predominantly containing black peat, will be pleased to hear that, according to the current status of Floragard’s trials, the advantageous principle of press pot production is likely to remain in horticulture.
For more information, please visit www.floragard.de