How to Plant Dahlia Tubers with Success

Learn how to plant dahlia tubers and get essential tips for growing better dahlias. Need to know about planting dahlias from tubers? This comprehensive guide will give you tips about preparing soil, caring for dahlias, keeping pests away, and storing them for the winter. Learn when to plant dahlia tubers, how to plant dahlia tubers in containers, and how to plant dahlia tubers outdoors. Planting dahlias from tubers is something I enjoy doing every year. With three different dahlia beds, I have a lot of tubers to plant. Last year, I planted 60, and they ALL came up! What are the secrets to successfully planting dahlia tubers? Read on for the easy and essential tips for how to divide, plant, and care for dahlia tubers in the spring and throughout the summer growing season. After years of dahlia-growing experience, I’m still trying new things, but have learned so much. Here’s a beginner’s guide step by step to planting dahlia tubers and growing dahlias. You, too, can have beautiful dahlia blooms all summer long and into the fall!

The Dahlia Solution

For me, gardening is a process of trial and error (and error, and error). It’s a constant learning experience. Sometimes there are planting experiments that are wildly successful. (Hooray for scarlet runner beans!) Then, there are plants that are just not meant to be grown in our yard. Hybrid tea roses, the classic beauties, never thrived where we planted them. We were constantly battling black spot, aphids, powdery mildew, and it was not a lovely experience for anyone. My visions of beautiful cut flower arrangements crumbled into dust. The solution? Dahlias! Interested in learning how to grow dahlias? Wondering how do you plant dahlia tubers? Read on for all you need to know about planting dahlias from tubers.

Dahlias to the Rescue

After fighting a losing battle with the sad-looking hybrid tea roses for over 15 years, my husband and I finally admitted defeat. My husband pulled out all of the dreadful-looking hybrid tea roses, and their former flower bed languished in neglect. We housed some plants there temporarily, but we were uninspired to do anything more. The south-facing sunny location was ideal for something, but what? Then, we had an idea. Do dahlias like full sun? Yes, they do, so that’s what we decided to plant. We were ready to learn. “Show me how to plant dahlia tubers!” I said to myself with enthusiasm.

A Successful Dahlia Planting Strategy

We had grown dahlias before, then lost them after digging them up and storing them. It got too cold in the garden shed where we had packed them in sawdust. A few years later, we decided to try growing a few more as an experiment up near our orchard. We tried not to care or get too attached to them, and decided to leave them in the ground to overwinter. Can you leave dahlias in the ground over winter? Ours returned, and have given us beautiful blooms for multiple years now. The area is well-drained, so the tubers didn’t rot. If you are worried about drainage or extremely cold temperatures, digging up will give you more peace of mind. Since we had such good luck with the few dahlia tubers we tried, we were ready for the next step: planting a true dahlia bed.

The Perfect Place for Inspiration

Where we live, in Oregon, we are fortunate to have a wonderful dahlia farm not too far from us. It’s called Swan Island Dahlias, and it’s a gorgeous place to visit in early September, when their annual Dahlia Festival takes place. We were so inspired! After some agonizing decision-making while paging through the catalog, we finally settled on ten of them. We departed with our free calendar, anticipating the promised arrival of the tubers in the spring. This was a few years ago, and since that time we have learned a lot about overwintering and storing the dahlias during the off-season. Whether I have new tubers to plant or am just taking tubers out of storage to divide and plant, I always get excited when it’s time to plant dahlias in the spring. I’m such a huge fan of dahlias that I designed an entire party theme around them.

Removing Dahlia Tubers From Storage

The spring weather where I live is often cold and rainy. I am not deterred! Even though the weather sometimes isn’t great for planting dahlias, I can still use the time to inspect the dahlias we have had stored in our garage.

So far wood shavings have worked well for us. We have a lot of them around due to woodworking projects, so it’s an economical choice. Other gardeners wrap their tubers in plastic wrap to store for the winter. One of our friends, an avid dahlia-lover, assures us that packing the dahlias in vermiculite is the best way to over-winter the tubers.

Maybe we will use vermiculite or plastic wrap if we are ever short of wood shavings. 

Planning a Time to Plant the Dahlia Tubers

You might be asking yourself, “When can I plant out my dahlia tubers? What month do you plant dahlia tubers?” Some of you may have tubers that you overwintered in storage. If so, you could pot your tubers in late February or early March and give them a start in a greenhouse. Can you plant dahlia tubers straight in the ground? Yes, you can. When to plant dahlias outdoors depends on where you live. We don’t have a greenhouse, and we live in Oregon, at about 1,200 feet of elevation. We live in plant hardiness gardening zone 8. For those of you who like to know which plant hardiness growing zone you are in, you can type in your zipcode on the Burpee website to find out. When do we plant dahlias where we live? In our zone, the optimal planting time for dahlia tubers straight in the ground is from the latter half of April through mid-May. 

When Are New Dahlia Tubers Shipped?

If  you are awaiting a shipment of dahlia tubers, the arrival date depends upon where you live and the company you are working with. When we ordered from Swan Island Dahlias, our shipment of dahlia tubers arrived in mid-April. We received the long-awaited box with our eleven (they included a free extra tuber) dahlia tubers, packed carefully, ready to be planted.

Choosing a Location to Plant the Dahlia Tubers

Where is the best place to plant dahlias? In the northern hemisphere, dahlias do best in a west or south-facing location. A spot that gets 6-8 hours of sunlight a day is ideal. The location should be well-drained so the tubers don’t rot. The location we chose to house the formal dahlia bed fit all of these requirements. 

Preparing the New Bed for Planting Dahlias

How do you prepare soil for dahlias? We raked the ground smooth, then followed the directions included with our package. The instructions directed us to dig holes 4 to 6 inches deep. Bone meal was recommended as an additive to be mixed in with the soil, but we decided to use potting soil and mix it in with regular dirt in each hole. Also, if you mix used coffee grounds in with the soil, slugs are deterred from eating the dahlia leaves. Yes! Anything to deter the slugs around here is a bonus (more on that further on down in the post). No coffee drinkers where you live? Good news! Starbucks has a free coffee grounds for gardeners program you can take advantage of. Not all stores participate, so check with your local shop to see if they offer this freebie to the community.

Should You Soak Dahlia Tubers Before Planting?

After we planted our brand new dahlia tubers, we learned that soaking dahlia tubers before planting is a good idea. You can place them in a bucket of water the night before planting. Will dried out dahlia tubers grow? The dahlia tubers we planted did fine without soaking. As long as there is some moisture in the tuber, the tuber should sprout. If you are preparing to plant dahlia tubers, either new or existing, you could experiment to see if there is any difference.

Organizing By Color and Height

Fortunately, we had saved the little catalog we marked our choices in. The catalog also included a description of each variety, detailing the size of the bloom, the color, and the plant height. Each tuber was marked, so all I had to do was determine which colors and sizes would look good together. (To easily create a layout plan for the dahlias, you can make a garden layout template in Google Slides.) Our dahlias were going to be planted in rows, which was perfect for my unwaveringly linear planting style. (I am artistically challenged, and have trouble arranging things randomly, as noted in this previous post about planting flowers in containers.)

Transplanting the Old Tubers

In addition to arranging the new tubers, we also needed to transplant the older dahlia tubers from up near our orchard. As we dug them up (they did fine in the ground over the winter), some were large enough to be divided into separate tubers.

Dividing Dahlia Tubers in the Spring

Can or should you divide dahlia tubers in the spring? Should you separate dahlia tubers? Some dahlia growers prefer to divide dahlias in the spring. Here is the main reason: You can spot the dahlia eyes more easily. When dividing dahlia tubers, it’s important to look for an “eye” or a little place where a nub or sprout is growing. What does a dahlia tuber eye look like? Here’s a photo. The arrow is pointing to the eye.

If you wait until the spring to divide, the eyes will usually be obvious. There may be a sprout already growing. I am always relieved when I can tell for sure there is an obvious eye on the tuber. You might be asking yourself, “How do I know if my dahlia tubers are dead?” If you cut away a bit of the dahlia and see clean, white flesh all the way to the “neck” where the eyes are going to be, then the tuber should be viable. If there is dark rot into the neck of the tuber, then the tuber is most likely dead. If I’m not sure, I stick the questionable tubers in a hole and see if anything happens. Will broken dahlia tubers grow? Yes, as long as the neck is still intact.

Some dahlia growers prefer to divide dahlias in the fall, and there are advantages to this method as well. When I divided my dahlias in the fall, I had fewer (and smaller) tubers to store. I gave away the extras at work (they were snapped up), then all of my tubers fit into one box. In the spring, when it came time to plant, I was able to organize all of the tubers in a wheelbarrow, rather than needing to have room to spread them all over the lawn.

Another advantage to having smaller tubers (or tuber clumps) to plant in the spring is the reduced sizes of the holes you have to dig. The holes can be a lot smaller, which will save you time and energy when planting. Here are some of the dahlia tubers in their holes, ready to be covered with soil.

Whether you divide your dahlias in the spring or divide your dahlias in the fall, it is nice to have a guide to follow. Need to learn how to divide dahlia tubers with confidence? For more details about dividing dahlias with confidence, read my how-to article.

When we divided the dahlia tubers that had overwintered in the ground, we left some tubers where they were and moved others down to the new bed.

Planting the Dahlia Tubers

We placed each tuber in the prepared hole, mixing in one part potting soil with one part regular dirt as we went along. If we could spot the eye on the dahlia, we made sure the eye was pointing up. How do you know how deep to plant dahlia tubers? Plant dahlia tubers 2 to 4 inches deep. The old stem should be right at soil level. 

How do you know how close to plant dahlia tubers? How do you know how far apart to plant dahlia tubers? We spaced the holes about three feet apart, because we have a large bed. You could space dahlias one to two feet apart if you have a smaller space. For our most recent dahlia season, we ended up with two rows of dahlias in the new bed, 18 in all, with seven still up by the orchard. We planted the rest of the tubers, 35 of them, on the sunny north end of our vegetable garden plot. I’m gradually turning the vegetable garden into more of a cutting garden, since we are now empty-nesters. We don’t eat nearly as much garden produce as we used to, so planting the dahlia tubers in the vegetable garden is a key part of my strategy to simplify my gardening tasks. That way, I don’t fall down on the job when it comes to harvest time. I just let the dahlias take up garden space and bloom away!

Can I Grow Dahlias in Containers?

Yes, dahlias may be grown in containers. In fact, a coworker gave me a very lovely dahlia plant in a container and it bloomed all summer long. Dahlias can make a great container plant. Here’s how to plant dahlia tubers in pots. An ideal pot would be 12-14 inches in diameter, depending upon the size of the tuber. A pot with good drainage is important. Fill about 1/3 of the pot with potting soil, then lay the tuber so the eye is facing up and is centered in the pot as much as possible. How deep do you plant dahlias in pots? Cover the tuber with a layer of soil about 1-2 inches deep. Be careful about filling the pot all the way to the top, as you want to avoid rot. As the tuber sprouts, you can layer on a bit more soil to anchor the plant firmly in place. When can you plant dahlias in containers? If you like, the containers can be planted about a month before the last frost date and started indoors. If you have large containers that remain permanently outside, those containers can be planted at the same time as you would plant dahlias in the ground.

Can You Grow Dahlias Indoors?

Yes, dahlias may be grown in containers indoors. If you would like to keep potted dahlias inside, a sunny location would work well. The size of container you use can be determined by the variety you choose to grow. Miniature dahlia varieties and dwarf dahlias make excellent indoor container colorspots. 

How to Plant Dahlias Outdoors After Starting Indoors in Containers

Maybe you were eager to get a jump on dahlia season by starting the tubers indoors but want to transplant them to an outdoor dahlia bed. Here’s how to plant dahlia tubers outside after starting them inside. For best results, the plants should be a maximum of one foot tall when transplanted. Dig a small, 6-inch deep hole. If desired, mix in a little bone meal with the dirt. Carefully remove the sprouted tuber and plant from the container. Place the tuber in the hole and pack the bonemeal-enriched soil around it.

How Long Does it Take for Dahlia Tubers to Sprout?

How long do dahlia tubers take to sprout? It can take four to five weeks for the dahlia tubers to sprout, depending upon the variety. Sometimes it takes longer if the dahlias were planted a little too deeply. Once the dahlias have sprouted, keep a close watch for pests, as I note further on in the post.

Caring for the Dahlia Tubers Once They are Planted

Do dahlias like dry soil? Dahlias like well-drained soil, you don’t want the tubers to rot. They do need to be watered regularly. My favorite way to water is with a watering wand to keep an eye on any problems in the dahlia bed. In addition to our designated dahlia bed, we also left some dahlias up by our orchard. The ones by the orchard do not get watered as thoroughly as the dahlias in our designated bed. They are too far away from the house for the watering wand to reach. I have to carry a watering can up a hill to get to them, so they definitely get less water than their counterparts nearer the house. When the weather is hot, I water every day in the morning when I water the container plants and the vegetable garden. In Oregon, we have quite a few cloudy days. Most of the time, I can stick to an every other day watering schedule.

Keeping the Pests Away

How do you protect dahlias from getting eaten by garden pests? Where I live, I’m constantly on slug patrol. How do I stop slugs eating my dahlias? I use slug bait. As a general gardening rule, I try organic methods first. We have tried many strategies to keep slugs off of our plants. Do coffee grounds sprinkled on top of the soil keep slugs away? Anything that is rough or sharp will help deter slugs. Some people use eggshells. We have tried many options, and the most effective is Corey’s Slug and Snail Killer. This is one instance when I have just had to use a non-organic approach.

I do have another way of dealing with slugs, but if you are a sensitive soul STOP READING. If slugs cross my path while I am out in the garden, I stomp on them with my rubber boots. I often don’t want to go to the garden shed to get the slug bait, and it’s a quick process. Now you know my dirty little slug-killing secret. Does that count as an organic method? I hope you don’t think less of me. I know of one gardener who regularly used scissors to dispatch slugs. Okay, on to another topic!

How to Keep Dahlias Blooming

Should I deadhead dahlias? Deadheading dahlias is one way to get the plants to produce more blooms. I try to deadhead the dahlias about once a week during the heaviest bloom time in late summer. I am generally a low-maintenance gardener, so I’m not always very vigilant about deadheading spent blooms from other plants. For dahlias, I take the time. Keeping dahlias upright is another important part of prolonging the blooming season. Staking dahlias before they flop over will keep the blooms coming. How long do dahlias bloom? When conditions are right, dahlias can bloom for as long as four months, all through the summer and into the fall. I love taking cut bouquets of dahlias to brighten the desks of my teaching colleagues after school starts.

Storing for the Winter

What do you do with dahlias in the winter? Some people do dig up their dahlias every fall and store them in a safe place for the winter. That didn’t work well for us before, but that’s because we had them stored in the wrong place. Our unheated garden shed was not a good choice. Now we know better. We have had good luck the past few years by storing the tubers in sawdust (which we have in abundance) in our garage. One of our friends, who is very generous about sharing his extra tubers, assures us that packing the dahlia tubers in vermiculite is the way to go. If you try it and that works well for you, please let me know!

Wondering What to Wear When Planting Dahlias?

There is no guarantee that the weather will be nice when planting dahlias. How can you be prepared no matter what the weather holds? Get some tips about what to wear for gardening in any type of weather!

Unique Gifts for Dahlia Lovers

Looking for the perfect dahlia gift for someone? If you have a dahlia-lover in your life, here are some fun gift ideas. Show an affection for dahlias with these creative dahlia-themed gifts.

Looking for More Garden Inspiration?

If you are interested in planting dahlia tubers in containers, check out my post about Flower Container Ideas for the Artistically Challenged for some creative garden container ideas. If you are searching for low-maintenance garden plants, my posts about easy-care old garden roses, foolproof perennials, and favorite flowering shrubs might be just what you’re looking for. Into simple garden do-it-yourself projects? Have a look at my post about making a simple pole bean tower you can use year after year. Check out the tips for the best companion plants for eggplant or best companion plants for rhubarb to learn what to grow with those beauties. As always, you could turn to the Garden section of this website. There are so many exciting plants to grow!

Inspired to Start a Garden Notebook

As a result of needing to keep track of what kind of dahlia we planted where, I decided to begin a garden planner notebook. It will have a page for each month, along with notes pages. We also recently unearthed our list of irises, which are in another area of our yard. I need to be better organized. If a garden planner notebook seems like a good idea to you, good news! I’m adding the 16 master pages to the free resource library for subscribers to the Fluxing Well blog. You can get it here!

Get the garden planner!

Free Online Garden Planner Layout Template

Now that you know how to plant dahlias, you might need a way to plan your garden layout. Whether you are planting vegetables, flowers, or herbs, or doing some landscaping design, this online garden planner can help you visualize your design and bring it to life. Arrange and rearrange the plants over and over, then print the layout when you are satisfied. With garden tasks that need your attention, this is one way to save time.

It’s fully customizable when you make your own copy and includes two editable chart pages for noting planting specifications.

Get my free online garden layout planner template!

What About Your Dahlia Experiences?

What are your favorite varieties of dahlias? Do you have any favorite dahlia growing tips to share? Whether you are wanting to know how to plant dahlia tubers in the ground, where to plant dahlia tubers, or any other essential tips for growing dahlias, I hope you’ve learned how best to plant dahlia tubers and gained some useful information about caring for dahlias.

Have a wonderful week, and may all of your dahlia endeavors meet with great success!

Lisa Mitchell is a wife, mom, and school librarian who likes to grow fruit, vegetables, and flowers on her family’s small Pacific Northwest farm. To learn more about what this website has to offer gardeners, click on over to the Garden page.

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