How to Acclimate Raspberry Plants
Acclimate (ac·cli·mate): "To become accustomed to a new climate or to new conditions. Also to harden off a plant."
Acclimating raspberry plants helps to avoid stress to new plants and transplants. It is our strong recommendation for plants that are leafed out and not dormant. Some of our raspberry plants arrive to you potted with tender new growth, since they were grown in the controlled environment of our greenhouses. This tender new growth can be sensitive to things like direct sunlight and sudden changes in temperature, so acclimating raspberry plants to their new environment will help provide them with a great start.
NOTE: This is part 2 in a series of 11 articles. For a complete background on how to grow raspberry plants, we recommend starting from the beginning.
Things that may cause injury to tender new growth in transplants:
- temperatures (below 50ºF or above 90ºF)
- frost snaps
- strong/direct sunlight
- wind
These conditions are more likely to occur during early spring, but can be expected during different times of year in different areas. Here are a few steps we recommend you follow to acclimate (or harden off) your raspberry plants before planting outdoors:
1. Upon arrival, keep raspberry plants in the pots they arrived in and place them in a sheltered, shady spot outdoors — like on a back porch. Leave them there for 3-4 hours and gradually increase the time spent outside by 1-2 hours per day. Bring them back indoors each night.
2. After 2-3 days of this acclimation process, begin transitioning the raspberry plants from their shaded spot to one that provides some morning sun. Return them to the shade in the afternoon. If this conflicts with your schedule, try moving the plants to an area that receives filtered sunlight instead, which is less intense than direct sun. Be sure still to bring them indoors again overnight.
- Water regularly as needed to keep the roots from drying out. If the soil in the pots is dry to the touch, then you know it’s time to water. You may occasionally mist the leaves with water, since the environment indoors is drier than outdoors.
- Observe foliage daily. If signs of leaf injury appear prior to planting, move those plants back into filtered sunlight and start from the first step again. Proceed to the second step when conditions improve.
- After 7 days, your raspberry plants should be able to handle the outdoor conditions, as long as temperatures are expected to stay between 50ºF and 90ºF. If daytime temperatures are expected to drop within the next day or so, continue to repeat the second step. Monitor your plants, and the weather, until conditions are more suitable for planting outdoors.
3. After 7-10 days, and if the weather conditions are right, your raspberry plants are ready for planting in a permanent location. For best results, try to plant tender plants on a cloudy day.
Please note: these are general recommendations. Your particular growing environment might require a slight variation on these guidelines, since some plants can take more time (or less time) than others to harden off. Factors like the current year’s weather, individual plants, and your location can affect the acclimation process.
