The dahlia is a genus of perennial and tuberous plants that are native to Central America and Mexico. They are incredibly popular and are closely related to popular flowers such as the chrysanthemum, the zinnia, the sunflower, and the daisy.
There are 42 different species of the dahlia, and many people create hybrids to get a unique appearance.
The flower forms are likely to vary depending on a variety of factors. They can be as small as 5 cm in diameter or can grow as big as 30 cm, which is almost the size of a dinner plate.
If you want to give your garden or your backyard a beautiful, colorful appearance, you should definitely consider growing dahlias.
The flowers are going to bloom all throughout the spring until autumn arrives, so it’s one of the only few plants that is capable of blooming for such a long period of time. That is one of the main reasons why they are so popular among homeowners and gardeners who want to give their place a splash of color.
Many people often plant the dahlia tubers in the ground and hope for them to grow over time, and if you provide the right growing conditions and take care of the plant, it’s definitely going to grow quickly.
But, what if you want to grow these flowers in pots?
Can You Grow the Flowers in Pots?
Many people are confused about whether they can grow dahlias in pots. If you look at most of the dahlias growing in your area or at a nursery, you will see that they are all planted in the ground. This creates an impression that growing dahlias in pots is not a viable option.
However, you should know that dahlias can be grown quite easily in pots, but they are going to require a bit of care. The process for growing dahlias in pots is a bit different from growing them in the ground.
First and foremost, you need to make sure that you select the right sized container for your plants. When looking for a container for the dahlia, look for one in which the tuber can be placed comfortably at the bottom.
If the edges of the tuber are bending from one side, there is a strong risk that your plants won’t grow healthy. Freshly planted dahlia tubers have a much higher chance of rotting, so it’s imperative that you choose a container that allows water to drain through it.
If the pot doesn’t have any holes at the bottom, it won’t be long before the dahlias begin to rot. You need to make sure that you create the holes or choose a pot that has proper drainage from all sides.
Here’s how you can get started with potting the dahlias.
Creating the Mix
To ensure the right growing conditions for the dahlias, you need to start off by creating the right potting mix. You need to choose a mixture that has excellent drainage qualities, such as bark or perlite.
Then, moisten it just a bit before putting it in the pot. Both of these are pretty great in terms of drainage. You need to then fill the container at least one-third of the way, and then lay down your tuber.
Put it flat in the pot. If there is a sprout, also known as the eye of the tuber, you should keep it facing toward you. It should always be looking up.
Then, you need to add more potting mix all the way up so that the tuber is properly covered, and only tiny parts are showing. Just make sure that the eye is sticking out.
It’s always best to label your pots and keep them on a windowsill, where they are going to get plenty of sunlight as well.
As mentioned above, there is a variety of different species of dahlias that you can choose from. You need to select one that best suits your space.
If you are looking to buy dahlia tubers, you should first read about them. There are plenty of online gardening stores that sell dahlia tubers, or you can visit your local gardening center for growing them in a container. For instance, the dwarf dahlia varieties are excellent for growing in a container.
Similarly, there are several low-growing varieties in the market as well, which are also excellent for growing in pots. There are certain species of dahlia that can grow as high as five feet, so if you are going to grow these, you will want to choose a bigger pot.
A single tuber usually requires anywhere between one to two feet of space, so planting one tuber in one container is generally the best idea.
Selecting the Pot
You need to pick a pot that is at least 12 inches by 12 inches. Heavy pots are an ideal choice because they won’t topple over when the plant grows to a certain size. If you are going to plant the largest varieties of dahlia, you need to choose a bigger pot.
The 24 by 24 inch pot is a suitable choice in this regard. It can hold around 25 gallons of soil, and you won’t be able to move it around easily on your own.
Certain varieties of dahlias are quite top-heavy, and a lightweight pot is just going to topple over. On top of that, you will need to add a stake on the taller varieties as well, so that’s going to increase the weight in the pot as well.
Plastic containers are generally not a suitable choice for this, because they are quite lightweight.
You need to choose containers that are going to be sturdy and won’t topple over easily. That is why you should choose terracotta or ceramic pots. They are stronger, more durable, and also heavier.
However, terracotta and ceramic pots are both capable of absorbing the water.
If you leave them out during the winter months, there is a strong chance that they will freeze and crack. Then, always check the bottom of the container to ensure that there are drainage holes.
When filling up the container with the potting mix, always ensure that at least 1.5 inches at the bottom are layered with gravel. Gravel dramatically improves drainage.
Preparing the Pot
A dirty pot is likely to spread diseases and can kill your plants before they grow properly. There might be hidden insect eggs, especially if the pot has been left untouched for a long while.
If you have just taken the pot out from a shed that you haven’t entered in a while, you should clean it thoroughly.
To get rid of all these threats, a thorough cleaning is all you need to do. A mixture of gentle soap and water is just what you need to prepare the pot.
Make sure to wash the residue of soap properly. It’s also incredibly important that you wash the pot, especially if it has been used for other plants in the past.
The Potting Mix
Perlite and bark both make a good mixture. Standard potting soil itself is quite porous, and will affect the quality of bud formation.
For an excellent mixture, you should use two parts potting soil, and mix it with one part aged manure or peat moss. A common mistake that many people make in such instances is that they think about using garden soil in their potted plants.
That is not a wise idea at all. Garden soil isn’t suitable for potted plants, and it’s going to get compacted very quickly, thus killing the tubers within a few short days.
Always buy soil that is labeled for use in potted plants for the best growth.
Planting the Dahlias
The best time to plant the dahlias is during the spring season. Anytime between early April and all the way until June is a great idea, especially if you are in the Northern Hemisphere.
The dahlias are quite sensitive to frost, so you should only keep the containers out in the open when you are sure that there’s no chances of a chill in the air.
If the weather is going to get bad according to the forecasts, you should bring your potted plants inside. So, what about people who live in frost-prone areas?
Well, if the weather gets chilly during the spring, you should start by planting your dahlias indoors, then move them outside as the weather begins to warm up.
Packing the Soil
We have already talked about the importance of putting gravel at the bottom and putting the tubers in the pots.
However, when packing the soil, make sure you leave a gap of at least five to seven inches from the rim of the container. Don’t try to pack it too tightly as that could compact the soil.
Dahlias like the loose soil, so it’s best to let it be that way. You will want to plant your dahlia at least six inches deep, and you will want to leave at least an inch from the surface of the soil to the rim once the planting process has been completed.
Watering the Soil
Now that the soil has been poured in, you need to get started with watering it. The soil should be dampened a little, but you don’t need to soak it all the way.
If you pour too much water inside, the small gaps in between that trap oxygen are going to be filled with water, which is going to suffocate your plant.
The best way to water the plants is to make use of a watering can instead of blasting it hard with a hose in your garden.
Remember, these are very delicate tubers and require a considerable amount of care, so you have to make sure that you do not use any kind of pressurized hose.
Mixing the Fertilizer
The next step is to mix a bit of fertilizer into the soil. Dahlias require a considerable amount of nutrients, and mixing the fertilizer into the soil is necessary. You need to mix it properly to the point where the roots are going to develop. This is going to provide an initial boost to your dahlias.
The best thing to do is buy a general purpose fertilizer that comes with slow release properties. There are certain organic options available in the market as well, such as the bone meal fertilizer. Or, seaweed fertilizer is also a great choice.
You can choose any fertilizer that is recommended for growing plants or vegetables. Do look at the product label to make sure that the fertilizer you are buying is suitable for flowering plants. There are several store bought fertilizers that come with N-P-K numbers.
The best choices for dahlias are 5-10-15, 10-20-20, and the 5-10-10 fertilizers. Fertilizers that have a higher amount of nitrogen are ideal for use at the start of the season, and you can then continue to reduce the nitrogen levels by selecting different kinds of fertilizer over the passage of time.
Before you start using the fertilizer, it is always best to check the instructions on the packet. Different kinds of fertilizers are designed to be used in a particular way, so make sure you adhere to the instructions.
Burying a Stake
As we talked about earlier, larger varieties of the dahlia require a stake buried in the pot. If you have chosen a variety that’s going to grow more than three feet tall, you need to make sure that you put a stake in. A wooden stake or a sturdy metal rod is important.
You need to bury the stake in before you plant the tuber. Always select a stake that is going to touch the bottom of the pot and is going to rise to at least three feet out of the surface of the soil. If the pot is 12 inches at least, a four-foot stake is the ideal choice.
As the stem continues to grow around the stake, you should tie it loosely around it.
The tuber should be planted in the soil on its side. The eye should be centered in the middle, as that is where the dahlia is going to sprout from. The best way to plant the tuber is to first place it horizontally, and then move it ever so slightly in an upward angle.
This way, the eye will face upward directly. If you look closely, you will realize that the eye looks very much like a bud. You will find it at the opposite end of the roots of the tuber.
Watering the New Sprouts
Within a few days, you will notice new sprouts growing out from the container. These are young and are going to require a considerable amount of care.
The first thing you need to do is stick your finger into the soil. This is important because you need to test the soil.
If the soil already feels moist to you, there is no need to put in more water. Using a hygrometer is also a great way to test the amount of water in the soil. If the soil is dry, you can just sprinkle a bit of water to moisten the surface in a proper manner.
Creating a balance is very important in the early stages. Remember, you don’t want the soil to dry out completely, but if you water it too much, the tubers are going to rot.
If you live in an area that receives a lot of sunlight and is generally cool, you won’t need to water the plants as much, especially until the first leaves begin to emerge from the soil.
However, if the temperature generally remains hot where you live, you will need to soak the soil from time to time.
Adding Small Amounts of Soil
As the stalk continues to grow, you will need to care for it. The young stalk is still relatively fragile at this point, so as it continues to grow, you should start adding a little bit of soil.
Continue covering the stalk right up to where the first leaves are, but make sure that the leaves remain above the soil.
You should continue adding the soil until there is just an inch remaining between the rim of the pot and the surface of the soil. The dahlia is one of the fastest growing plants, and you will notice a considerable amount of leaves within the next couple of weeks.
Within eight weeks, you will probably get to see your first dahlia bloom!
How to Care for the Dahlia Plants
Caring for the dahlia plants is also very important. If you have made this much effort to plant them properly in pots in your house, a little bit of care is all it takes to keep the plants healthy.
For starters, you should know that dahlias require at least six to eight hours of sunlight on a regular basis.
For the best possible results, you should always choose a spot where the plant is going to get uninterrupted sunlight from the early morning until midday. Then, during the afternoon, you need a spot that will provide at least partial shade to the plant.
If you live in a hot climate, you should know that the intense sun is going to burn the plant out. Protecting it is important.
But, what if you are starting the plant indoors? In the early spring, your plants are going to require at least partial sunlight, so keep them near a windowsill or in an area where there’s lots of sunlight at your place.
You can also use artificial lighting to supplement its growth, though make sure that you do not put the light too close.
It should be set at least six inches above the top rim of the pot, especially for the newly planted tubers.
Now that the stalk has grown beyond the rim of the pot and there is considerable foliage on your dahlia plant, you should change your watering routine.
You need to water your plants at least two or three times a week. If you are growing the plants in a hotter climate, you need to water them on a regular basis.
As long as the pot has decent drainage, you don’t need to worry about the soil getting waterlogged. You have to check it, however. If the soil is getting waterlogged from time to time, you should stop watering it on a daily basis.
Tying the Stalk to the Stake
As the height of the stalk reaches one foot, you should tie it properly to the stake. A standard cable tie is a useful choice, though you have to make sure that it’s not tight.
Nylon strings, or even twine is a good choice in this regard. You need to tie it at intervals of one foot so that it remains in place. Just make sure that you do not tie it up in a knot tightly.
Fertilizing the Flowers
As the blooming season approaches, you also need to fertilize the flowers regularly. Liquid fertilizers are a great choice in this regard and are readily available from local gardening shops.
Find a fertilizer that contains a higher amount of phosphorus and potassium, as it will dramatically improve the development of the roots. Always apply the fertilizer as is mentioned on the back of the product.
Pruning and Care
You need to prune the dahlias carefully from time to time to keep them healthy.
After every few weeks, you should also apply a mixture of insecticide on the plants to keep them healthy. You never know when a pest infestation might start to grow in your beloved dahlias, so it’s very important that you care for them.
By following these steps, you will be able to grow lots of dahlias with minimal effort. Make sure to keep a check on the plants from time to time to ensure nothing is wrong!
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.