Environment Canada has placed most of Southern Ontario under a Heat Alert for the next few days. It’s the time of year for sticking poinsettia cuttings, and cuttings of any floral crop are susceptible to extreme temperatures. Plants are just like people, crank up the heat and they put all their energy into just surviving the conditions, not forcing roots. Stressful conditions at rooting can lead to poor plant quality and cause defects that will be seen later in production like poor branching and leaf deformities.
If you stuck earlier in the week, or are planning to early next week, here are some tips to help get the majority of your new cuttings through this stressful weather:
- If they look of poor quality, they will not root well. Only stick good quality cuttings.
- If cuttings can’t get stuck immediately place in a cooler held at 10-13˚C. Check to make sure it’s holding the correct temperature!
- Only work with the number of cuttings that you can stick in a short amount of time outside of the cooler. Consider working in the cooler if possible, or working in the coolest part of the day (early morning) if not.
- Misting is important for keeping cuttings turgid (they don’t have roots!)
- Mist so the leaf surface is constantly moist without over wetting the media.
- Maintain relative humidity in the prop environment at near 100%.
- Mist based on the cuttings, not what has “always worked”.
- Night temperature over the weekend will be high! If at all possible, reduce night temperatures to 18˚C during the first few nights after sticking. Lower night temperatures help cuttings get established faster.
- Leaves rolling inward are a sign of dry cuttings in a HOT environment, use shade curtains and propagation tents to your advantage.
- Maintain light levels. Higher light means more mist will be needed. More mist = higher temperatures = heavy wet media which is difficult for the plant to root in. Keep it shaded!
Most importantly: MONITOR, MONITOR and MONITOR some more!
Remember that the heat, especially if it sticks around for a while, may cause your cuttings to lag behind normal production schedules. Keeping them as “stress-free” as possible will ensure the highest rate of survival.