Over the last several years we’ve heard many reports of poor quality cuttings. There are a range of causes, often due to the interconnectedness of our sector across the world. Staffing shortages along the supply chain and reduced or delayed air transit can affect our shipments. We’ve gathered resources from various experts and tried to compile them here for you to reference. While it’s basic information, it’s good for a refresher and for when things get overwhelmingly busy. Read on for some tips on getting the most out of your cuttings this summer to ensure healthy crops this fall and winter.
Before Cuttings Arrive:
Sanitize, sanitize, sanitize! Now’s the time to prepare for incoming poinsettia and fall mum cuttings. Make sure benches, irrigation lines, drippers and misting equipment has been thoroughly cleaned. Use Virkon or a quaternary ammonium product at the recommended rates. These products are only effective if the surface is clear of any residual growing media and plant debris so be sure to give everything a thorough scrub first. Make sure to rinse everything well after using these products to avoid potential phytotoxicity in sensitive cuttings and young plants. Ensure your water treatment system is working and consider proactively sending in water samples to the lab to identify any lurking issues before the season starts.
On Receipt:
Immediately unpack the box and inspect cuttings – anything that looks suspect (e.g. signs of disease, pest damage, watery looking, has a rotten smell to it) should NOT be stuck. Too often we hear growers say, they shouldn’t have stuck cuttings because they didn’t seem quite right, but they do it anyways! Save yourself the hassle and inputs from the beginning. If you suspect an issue, take lots of pictures and follow-up with your supplier ASAP to see what can be done.
Check the temperature of your cuttings as they arrive. This can be done using a temperature gun or sensor from your local hardware store. If the cuttings in the centre of the box are still around 10-12C, they’ve likely remained in the cold chain. But if the middle of the box cuttings are more like 18-20C, they may have been sitting outside of a temperature controlled truck for some time. These cuttings should be put in the cooler as soon as possible and watched for signs of stress at potting up after a cooling period. If you have concerns, follow up with your supplier.
Storage:
Of course it’s best to stick cuttings as soon as possible, but this isn’t always practical. Before storing them in the cooler for another day, make sure that you unpack the bags from the box and space them out to speed up the cooling process.
The bags that cuttings come in can trap ethylene gas, which can affect cutting quality and lead to breakdown. If possible, and if you will be storing the cuttings for a longer period, consider opening or fully removing the cuttings from the bags to prevent ethylene build up.
Ideally, your storage space should be cool and humid. Make sure it’s checked periodically to ensure it’s holding the temperature you want, and that the environment is consistent (not hot or cold spots). Poinsettia and fall mum cuttings should be stored around 10-12C. Consider using a a basic thermometer in each cooler in addition to any inline sensors to provide confidence that your temperature readings are correct. At the same time, check to make sure the misting system is working as intended in the cooler. Make sure moisture is not accumulating on the floor, and keep the cooler free of plant and growing media debris.
Handing and Sticking:
When cuttings come out of the cooler their stems should be turgid and strong. Don’t stick anything that appears to have deteriorated further from receipt through the time in the cooler.
When sticking cuttings, make sure your staff are consent in the way cuttings are placed in the pot or starter plugs. This attention to detail can pay off later more even growth and more uniform plant canopies. Consider having a meeting or posting instructions (with visuals) to remind workers on the sticking and potting lines how important their work is.
For poinsettias, you want to choose a growing medium that holds on to moisture but also leaves enough air-space for new roots to develop. Ellepots or oasis plugs are still popular choices. Ensure that moisture is provided regularly, especially in the first 5-7 days and especially when it’s sunny and hot. Try to keep a high relative humidity (>80%) in the propagation area if possible.
If you notice rooting is taking longer or isn’t as strong as in years past, make sure to investigate the cause. Formulation changes in rooting hormones or media may play a part, along with the growing environment and cutting health. If you are trialing a new or new-to-you product (e.g. rooting hormone, growing media, a biostimulant) make sure to trial it before using it exclusively. Having the comparison to your normal production can help you determine if there are benefits.
Other Resources:
Ball has a webinar series all about “Success with Cuttings”. Presented by Dr. Todd Cavins and Dr. Nathan Jahnke, they talk about everything from receiving cuttings to moving into the stages of propagation. Try the Receiving and Storage and Proper Storage = Happy cuttings episodes to get started. They also have a poinsettia specific series complete with propagation tips.
An oldie but a goodie! Check out this article in Greenhouse Product News on Reducing Shrink in Propagation by Rodger Styer.
Perfecting Propagation in Grower Talks is a comprehensive article by Dr. Jim Faust from Clemson University.
Your supplier might have other resources to share like culture guides for specific varieties.
Photo credits:
https://hendriksyoungplants.com/en/young-plants/unrooted-argyranthemum-cuttings
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