Lifting And Replanting Dahlias. Step By Step Guide
The time to lift dahlias for winter storage is just as the first frosts blacken the foliage or when it naturally begins to die back. Remove the foliage and cut back the stems, leaving about 20cm of each one attached to the tuber.
Fork gently around the plant, leaving a radius of 25 to 40cm from the main stem, depending on the amount of growth it has made. Gently lift the root, taking great care not to damage the tubers. Now carefully remove the soil from around the tubers.
Heavy soils may need to be washed off with water from a hose or tap. Place the plant upside down in a box so that any moisture can drain from the hollow stem. Store in a dry, frost free place and remove the soil from the tubers once it has dried off.
Dust any damaged tubers with a fungicide such as yellow or green sulphate of ammonia and then place in boxes of barely moist peat. Over winter in a dry, well ventilated, cool, frost free place.
When green shoots emerge in spring, water sparingly to keep the compost moist. In late spring or early summer, after all risk of frost has passed, choose a sunny, sheltered spot and prepare a deep planting hole.
Add a generous quantity of well rotted manure or a long term granular feed, and mix well into the soil at the bottom of the hole. Carefully lower the dahlia into the prepared hole. Add more soil or compost around the plant as necessary to bring up to soil level.
The hole should be bigger than the dahlia so that there is room to spread out the tubers. Adjust the whole depth if necessary so that the soil level is the same as the previous year as this level can be seen on the plant.
Gently firm the soil surrounding the plant, making sure as you do so that there are no gaps or air pockets, either around the plant or between the tubers. Firm the soil down first with your hands, gently and carefully, and then more decisively with your foot. Water the plant and the area around it and then add a layer of mulch.