Dahlias can be fairly easy to grow with the right care. Here are some tips to start you off with a confident green thumb!
First a little information about Dahlias.
Dahlias grow tubers which are similar to a potato (people often confuse them with bulbs which is different). Tubers multiply, so by fall the one tuber you planted will have many tubers of which you can divide up and multiply your stock for next spring!
Dahlias are not cold hardy, meaning they will not overwinter in the ground in cold zones like mine (zone 4). So if you would like to save them for next year, simply dig up the tubers AFTER the first frost in fall. Store the tuber in a paper bag filled with saw dust and store in a sealed container in a cool location - preferably 40 degrees. In spring you will need to divide the tubers. More on that in another blog.
1. Choose a location with at least 6 hours of direct sun (the more sun, the better!) and well drained, fertile soil.
2. Plant AFTER the threat of frost has passed which around here is Memorial Day. The soil should be warm and not soaking wet.
3. Space tubers or their starts 18” apart. For tubers, dig a hole about 4-6" deep and wide enough to accommodate the tuber. Place tuber in the hole with the "eyes" at the top (or lay it on it’s side) and back-fill the hole gently, covering the tuber completely with a few inches of soil. Do not use mulch on top as it makes it difficult for the sprouts to form. I like to put a dusting of bone meal in the hole with the tuber.
4. Stake Dahlias to prevent tipping over from wind and heavy blooms. A tomato cage works as well as a t-post with twine tied to the stalk.
5. If you are planting many varieties of Dahlias, make sure to label them when you put them in the ground.
6. DO NOT WATER THE TUBER after planting, unless the soil is super dry. You want the soil to be just slightly damp. Too much water can cause the tuber to rot. It's also wise to check the weather and avoid planting right before a huge rain storm.
7. Once the plants have sprouted (or if you start with a sprout), you may begin watering regularly. When plants reach about 8", begin fertilizing with all purpose liquid fertilizer about twice a month.
8. When they reach about 12-16" tall, pinch back leaving the bottom 3-4 sets of leaves. This signals the plant to produce more branches (and more blooms).
9. Plants begin to bloom in late July and produce heavily until the first killing frost of the season.
10. Harvest blooms when they are open and place in water immediately. A Dahlia is past it's prime when the petals are soft, satiny and tired looking on the back of the bloom.