Dahliasforcing
Forcing Dahlias – how to force dahlias in a pot?
To enjoy your dahlias for a longer period? That's possible by forcing dahlias. Forcing dahlias means bringing the dahlia bulbs to bloom earlier than they would naturally do outside according to their natural rhythm. By forcing dahlias, you grant yourself an everlasting summer with the most beautiful dahlias.
Forcing Dahlias can start from February to March
You can force dahlias by planting your bulbs indoors in a pot before the planting season begins. Do this between February and March. April is also possible, but it leaves less time for the plants to develop early. When forcing dahlias in winter, the plants can go outside around May. Mid-May is often the best time because by then, the risk of frost has mostly disappeared, and we are truly entering summer. Forcing dahlias still allows the option to keep them in their pots in May or to plant them in the garden.
The advantages of forcing dahlias in a pot
One advantage of forcing dahlias in a pot is that they get a head start in growth (and therefore feel a bit more comfortable in the summer). Additionally, indoors, young leaf shoots are protected from slugs, making your plants safer. Mature, dark green leaves are not as appealing to slugs. Forcing dahlias means you can enjoy a magnificent sea of flowers for a longer time, right at home!
Good to know: Forcing dahlias does not shorten the blooming period. Your plants will bloom just as long as usual, typically until late autumn when frost reappears.
Forcing Dahlias - the Steps
1. Planting Time Between February - March
The best time to force dahlias is between February and March. From May onwards, they can be moved outside in pots.
2. Materials Needed for Forcing Dahlias
When forcing dahlias, you won't need much:
- One flower pot per dahlia tuber (approximately 25 cm in diameter. The pot should have drainage holes in the bottom).
- Potting soil
- Water
- Fertilizer
- Lots of love
3. How Much Potting Soil Should You Use?
Try to leave about 7-10 cm of space between the potting soil and the rim of the pot (approximately the width of your hand).
4. What Fertilizer Can You Use During Pre-growth?
Pre-growing dahlias doesn't limit your options when it comes to feeding. Especially at the time of planting, it's important to provide the necessary nutrients to your tubers. Dahlia grower Peter offers you three options to choose from:
- Spread 10 to 20 granules of NPK 12+10+18 fertilizer (12+10+18 is a product name).
- Calcium ammonium nitrate (a type of fertilizer suitable as a nitrogen fertilizer).
- Natural compost (helps improve soil structure. Good for more biodiversity!)
TIP: You can purchase natural compost from various retailers, such as Tuindirect. Alternatively, you can plant dahlias with compost from a farmer near you. Avoid using fresh manure as it contains too much nitrogen. Visit Milieu Centraal for more information on fertilization.
5. Dahlias pre-sprouting is best done at a temperature of 15°C to 20°C
Pre-sprouting dahlias is optimal at a temperature of 20°C. This is often the average temperature indoors. Pay close attention not to deviate from the indicated temperature.
6. How to water during pre-sprouting?
Try to avoid tap water
Tap water is often 'too hard' - this generally applies to any plant - because it contains minerals and lime. Pre-sprouting dahlias, and essentially always, is best done with rainwater or, for example, ditch water.
Moisten the potting soil sufficiently after planting
Pre-sprouting dahlias in a pot means that the soil should be lightly moist. For a pot with a diameter of 25 cm, you can think of a maximum of half a cup of water. Do not give more! Too much water will cause the bulbs to rot, and then all your effort will have been in vain.
Ensure the soil remains sufficiently moist
Pre-sprouting dahlias in a pot means paying close attention to keeping the soil sufficiently moist. Not wet! How often you need to water depends on several factors. For example, do you have a plastic or terracotta pot (clay), and what is the temperature like in your home? So, keep a close eye on it.
TIP: A terracotta pot, due to its properties (made of clay), can breathe along better with your plant and absorbs (excess) water more quickly. Your dahlias will appreciate that. However, because of this, the soil may dry out a bit faster. So, water a bit more frequently.
7. Moving Pre-grown Dahlias Outdoors (in Pots) from May
If you've been pre-growing dahlias from winter/spring, then the plants can be moved outdoors when the night frost has definitively disappeared. Usually, this is from May onwards. Mid-May is often the optimal time.
TIP: When bringing the dahlia bulbs outdoors in May, gradually acclimate them to the temperature. For a week, sometimes two, gradually increase the time the dahlia bulbs spend outdoors. Also, remember: whether pre-growing dahlias or planting them directly in the garden, your plants absolutely dislike large temperature fluctuations.
8. Planting Dahlias in the Garden
If your dahlias are ready to go outdoors, you're still free to decide whether to leave them in their pots or plant them in your garden. If you want to plant dahlias in your garden, read on.
Once you're there, follow these steps for dahlia care.
Meet Peter
Meet the dahlia grower who accompanies you on your journey from bulb to flower.
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