In-house propagation has always had its upsides and downsides. A few things make it appealing: the potential for improved quality and reliability, reducing the risk from pests and disease; improved flexibility to meet demand. But there’s the costly investment to create a propagation space that ties up staff and equipment and the industry loss of specialist skills.
Because the UK has now left the EU, the EU plant passport is no longer valid in Great Britain. Growers must have a phytosanitary certificate (PC) to import plant material from the EU.
Historically many growers in the UK imported plug plants and young specimens to grow on. While this is still the case, a large proportion of Fargro’s customers have started to propagate their own stock.
So, if you’re thinking of heading down that route, here are five points to keep in mind for successful propagation.
1 Start strong
Nursery crops can propagate many healthy plants but having stock plants allows for a greater level of control and ultimately better quality. Choosing a healthy stock plant from which to take cuttings, one that is true to type and propagates well, is a key first step. The stock plant needs to be large enough that cuttings don’t harm it. The donor plant shares both its good and bad characteristics, so choose wisely. The AHDB Hardy nursery stock propagation guide is an excellent source of information on your propagation journey.
2 Find the best stems for cutting
Timing and the type of cutting used impact the rooting. Semi-ripe and softwood cuttings can be slower rooting than others. Stem cutting remains the most common form, most being nodal although many plants root well from an internodal cut. Often, it’s possible to make several individual cuttings from the same section of stem material. There are several other forms of cutting such as heel cuttings and basal, but do research before you head on this road to find what is most effective for your crops.
Newer growth is easier to root than woody or older stems. Look for a stem with a node along the stem where a leaf or flower bud attaches. This is where new roots emerge. The cutting needs leaves for photosynthesis to generate energy. But too many leaves take energy from rooting, and rooting is what you’re after at this stage.
3 Use a rooting powder
Some plants root easily but many growers find a rooting powder stimulates root initiation and improves the propagation. There are several different rooting powders on the market depending on the type of cutting. Use rooting powders containing auxin to stimulate root initiation and production. The Rhizopon range is market leading with different strengths to meet the needs of individual crops. A full rooting guide is available through Fargro.
4 Prevention is better than cure
Cuttings are prone to disease. Damping-off diseases for young plants present a significant risk. Proper hygiene and irrigation management go a long way to prevent issues. But integrating a product like T34 biocontrol to the growing media reduces the risk. T34 contains Trichoderma asperellum, which colonises the growing areas and rootzones. The fungus creates a physical barrier against the pathogen and helps growth as it competes with pathogens for space and nutrients. Through a process of hyperparasitism, T34 Biocontrol grows into and infects the sclerotia and hyphae of the fungal pathogen. It also induces plant disease resistance mechanisms.
5 The perfect environment
Cuttings are highly sensitive to their environment. Conditions that are cold and damp delay rooting, increase failure rates and the likelihood of disease and nutrient deficiencies. Optimum conditions vary from crop-to-crop, so additional, specific research is always needed, but generally, high humidity around 80-90% and temperatures in the low 20oC are best.
And these conditions are, of course, ideal for pest and disease development so having a specific IPM programme for your propagation area is key to a successful crop.
Fungus gnats are often an issue, Sciarid fly larval stages in the compost feed on roots and can kill seedlings. Being familiar with their characteristics and methods of control is vital for a successful propagation unit.
Please contact our Technical Team on 01903 256856 or email firstname.lastname@example.org to speak to a specialist about your propagation needs.