Wait until just after the first frost. Cut the withered foliage back to three inches above ground level. [2] X Research source
Avoid composting diseased plant matter as doing so can spread infection the infection to other plants.
60 to 70 degrees F is an ideal temperature for rhizome storage. It should not be less than 50 degrees Fahrenheit (10 degrees Celsius). [6] X Expert Source Jon RowlandPlant Specialist Expert Interview. 7 September 2021. Try not to let them be exposed to sunlight.
You can also use a cardboard box if you make some ventilation holes to let air circulate. Avoid letting the bulbs touch each other and put moss or vermiculite between them.
Your Calla is more at risk of rotting because of the winter rain rather than the frost so avoid planting if the ground if waterlogged, even if the weather is mild.
Once flowering ends, give the pot a feed with a potassium-rich fertilizer (one suitable for tomatoes will do). After that, cease watering your container-grown Calla lily and move the pot to a cool dark area once the foliage withers away. A dark corner of a garden shed is suitable. Don’t water your plant again for three months and avoid cutting the foliage until it has withered away.
This means that they can survive in temperatures that do not drop below 30 to 35 degrees F (-1. 1 to 1. 7 degrees C). [10] X Research source
Do this in the fall before the ground gets cold.
Mid-spring is usually a good time to move them outside again.
Leave about 12 inches (30. 5 cm) of space between each of your rhizomes. Once they are in the ground, give them a good soaking and then continue to keep the soil moist but not waterlogged as they grow.
Continue feeding container-grown Callas throughout the flowering period.
