16 Oct Growing Guide For Dahlias
I normally aim to have my Dahlias in the ground by Melbourne Cup Day. The main issue with timing is to not plant them too early in spring as if there are any later frosts their new shoots may be burnt off. If you live in warmer climates, you could have them in the ground early October.
Site selection
Dahlias prefer a location where they will receive approximately 6 – 8 hours of sunlight with some protection from afternoon sun. They like a well drained organic soil
Soil Preparation
I aim to improve the existing soil with composted manure such as sheep and cow manure. I also used a premium planting compost. It is best not to use any pig or poultry manure in the beds for Dahlias as it can be too rich. Dig compost and manure through the existing soil thoroughly. Ideally this soil preparation should happen up to 2 – 4 weeks before planting – you would then water the area as you would if there were plants growing in the soil.
Planting
Dig a hole approximately 10 – 15 cm below ground level and approximately twice the width and length of the tuber.
Lay the tuber on its side with its eye facing upwards. The eye will be located closer to the neck of the tuber whilst the other end will be the tail. Angle the tuber so that the tail sits slightly lower than the neck.
Lightly back fill the soil over the top of the tuber
Stake the tuber with at least a stake on either side of tuber – place stake in ground before you back fill with soil so you don’t risk stabbing the tuber with the stakes once they are underground. The support required for the Dahlia will be dependent on the size of Dahlia you are growing. It will also be determined by how you are laying out your Dahlia plants. For example, if planting in a row lay out a line of stakes with string in between to give support. If plant single tubers using a tripod like arrangement may be more suitable.
Spacing
This will be dependent on the species however 400mm is a good general guide.
Watering
Don’t water the tuber until you see some shoots coming through the top of soil. Once growing above the soil water deeply but not too often. They prefer to be kept on the slightly dryer side of moist
Fertilising
Throughout the season they will enjoy having applications of a weak seaweed emulsion applied. They need a fertiliser with lower levels of nitrogen.
Growing
When your dahlia plants reach around 30 – 40cm above the ground ideally you should tip prune or pinch out your dahlia plant. This is done by pruning off about 5 – 10 cm from the central stem. This will help encourage your dahlias to branch more which will lead to producing more stems and therefore flowers. As the plants start to flower it is good to pick the flowers regular and or remove any damaged or dead flowers. This will continue to encourage the plant to produce more flowers.
Picking
It is always best to pick your flowers in the coolest part of the day. This is when your plants are most hydrated and the flowers will suffer the least amount of stress.
If you would like to see some videos of what we discussed above, go to the Dahlia Highlight on my Instagram page here.
