How to Get Your Tubers
Dahlia tubers are now sold our for the 2020 season. Please check back again for our availibility in 2021.
We have been growing dahlias since well before the first season of River and Sea Flowers. These blooms come in a huge diversity of colours, shapes and sizes. They produce stem after stem of beautiful blooms from early August till first frost.
Dahlias grow from tubers, a potato-like lump that puts out a growing eye from near where they were connected to the original stem.
Each tuber will multiply over the growing season so that when you dig up your plant in the fall and divide it you will have more to plant next year.
How to Grow Your Dahlias
Dahlias can be planted in the spring when the soil has warmed and once the threat of frost has passed, usually late April in our area. You can plant them right until early June. Choose a location in full sun with good drainage and prepare your planting bed by loosening the soil. Incorporate some good quality compost. Dig a hole for your tuber so that it will be covered by about 4-6" of soil. Plant your tuber horizontally and with the eyes (growing points) facing up to the surface. If you don't see obvious eyes yet, don't worry! They can take a little while to wake up. Cover with loose soil. We plant our dahlias 12-16" apart.
Different varieties can grow to be different sizes so expect your plant to be between 2'-5' tall. They will require some support, either with a bamboo cane or a tomato cage. Don't water your tubers until they emerge from the soil. Over watering will cause your tubers to rot. Young plants don't need a lot of water but once they are well established they can be quite thirsty. Water well and deeply 1-2 times a week. Avoid getting the foliage wet. Cut your plants back by half when they are about 12" high. This encourages them to branch, which will give you more flowers as well as keeping the stalks from becoming too top heavy.
There is no need to pick your flowers if you would prefer to enjoy them in your garden. Should you wish to bring them inside or share them with others, start with clean sharp snips and a clean bucket of fresh water. Cut the stem at least 12" long just above a pair of leaves. New shoots will emerge from here to give you even more flowers. Even if you do not pick your flowers, remove spent flowers regularly to encourage your plant to continue to flower.
In the fall, after a killing frost, the foliage and flowers will turn black. Cut the plants back to about 6" above the soil and wait one to two weeks before digging them so that the skins of the tubers can set. Using a digging fork, loosen the soil about 12" from the stalk. Carefully lift the clump from the soil by the stalk taking care not to break the tubers from the main stalk, gently brush away soil. If the soil is heavy and hard to remove you can wash it off but don't use high water pressure as you may damage the skins of the tubers.
Trim back the stalk to remove green succulent portion.Leave your tubers in a warm spot to dry for a few days.Pack the tuber clump into a bin or box containing a loose material such as wood shavings, vermiculite or sawdust. Store unsealed in a cool place that will remain above freezing. Check your tubers regularly to make sure that they are not shrivelling (low humidity) or rotting (high humidity). Remove any rotting tubers immediately.
Tubers can be divided in either fall or spring, though it is usually easier to do in the spring. Using a sharp utility knife or pruners separate tubers from the main stalk making sure to keep a portion of the main stalk attached to the tuber. This is where the eyes develop. Discard any tubers with broken necks or that don't have a part of the main stalk. Look for raised bumps where the tubers meet the stalk as these are eyes, the growing points for the next season's stems. Sometimes eyes are very difficult to see or are even not apparent until the tuber has "woken up". If you are having difficulty seeing the eyes bring them into a warmer place and they will emerge more quickly.
There are many resources online. Google for photos or look up a YouTube video. There isn't only one way to do it and it's okay to make mistakes as you learn how to grow dahlias!