Live from June 5 to mid October in Nova Scotia, zone 6a. Its mostly solid rock property in my area with just a few inches of soil. I want to build a cutting garden and therefore need to do it by building large raised beds.
Am interested in Ranunculus and Dahlias. Have read dahlias dislike potting soil so not sure what to use? Is Ranunculus the same? Never planted a cutting garden, let alone on rock. Approximately how many flowers does one form of Ranunculus give….not sure how many to buy. Thank you!
Thank you for your question. Given that you are gardening on rock with very little soil, your decision to grow your cutting garden in raised beds is wise. For raised beds built on a non-permeable surface, ensure that there is sufficient drainage material such as gravel or fine stones in the bottom to a depth of about 3 inches. You will want good quality, rich soil for your raised beds that you should be able to purchase from a local garden centre. Make sure the soil contains plenty of organic matter so that it drains well. This will be good for both Ranunculus and Dahlias. Triple Mix with added compost would be suitable.
These articles may give you some additional information about building a raised bed.
Ranunculus and Dahlias are grown from tubers and should be treated as annuals in zone 6a.
Ranunculus asiaticus (Persian buttercups) are the showy ranunculus seen in florist shops that make the best cut flowers. These grow from claw-shaped tubers that can be planted outdoors in your raised garden when all danger of frost has passed. The tubers should be planted in full sun (6-8 hours/day) about 2 inches deep with the claw facing down, 4 – 6 inches apart. Water well after planting and let the soil dry out before watering again. The plants need water around their roots, but will rot with poor drainage around their crowns.
Ranunculus tubers can range in size from just over 1 inch to just over 3 inches. Generally, the size of the tuber determines the number of flowers that it will produce. The largest tubers may yield up to 35 flowers with the smallest yielding around a dozen flowers. Spacing of the tubers for planting will also depend on their size. If the tuber is around 2 inches in diameter, space about 4-6 inches apart. For very large tubers space them up to 8 -12 inches apart.
Dahlias come in a large array of colours and shapes, sizes and forms. They grow from tubers that should be set out in your raised garden after there is no risk of frost. Dahlias like a full sun location. The tubers should be placed with the “eye” (the point on the top of the tuber) facing up. Check the labels, but most tubers should be well spaced, 18-24 inches, apart and about 4-6 inches deep. Many dahlias require staking and it may be preferable to stake beside the root when you plant the tuber. Otherwise, take care not to damage the tuber when staking after the plant is growing. Be careful not to overwater young plants in order to prevent rot.
Neither Ranunculus nor Dahlias will survive the Nova Scotia winter. You may gently dig up the tubers in the fall and store them over the winter for planting the following year. Let the tubers dry in a warm, sunny location prior to storing. Dahlias store well covered with barely moistened peat, sand or soil in a bag or pot kept in a cool cellar. Ranunculus tubers can be stored in peat moss in a paper bag in a cool, dark location.
For more information on growing Dahlias you may want to refer to this information on the Toronto Master Gardener website: