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Grow Dahlias in Pots

How to grow Dahlias in pots and containers. Perfect for patio gardens or anywhere you want to grow these gorgeous plants. Got voles and gophers? This keeps your precious dahlia tubers safe!

Do you want to grow dahlias in pots? Many want to grow dahlias but think they can’t because they don’t have a big garden area. Or maybe you have a problem like me.

I have a ground critter problem, namely voles and gophers that think my Dahlias are their personal dessert tray. So I have had to switch to pots and containers to grow the Dahlias in.

Cafe au Lait Dahlia in Secret Garden planted in a pot
Cafe au Lait Dahlia planted in a galvanized bucket

Last year voles really devastated my dahlia tubers, I saved just a few and they are growing well this year but in containers and pots so today I will show you how you can too.

When to Plant Dahlias

Dahlias like it warm so be sure you are well past your frost date before planting out in the garden. They grow best in soil that is 60 degrees or warmer.

I start mine in the greenhouse to get a jump start but you can just get your containers ready and set them out then wait for the soil to warm with the sun.

The great thing about pots is the soil warms faster than in the ground. A big plus.

Pots for Dahlias

You can use many containers or pots you already have like I did and I bought a few others that were not really planters but I made them into it. I liked them and they were relatively inexpensive.

Like this galvanized drink container I bought from Wal-Mart.

galvanized drink tub with holes drilled in it

Make sure to drill plenty of holes if your container choice needs it, Dahlias like good drainage.

Dahlias need about 12 inches or more of space per tuber and the container should be at least 12 inches deep.

Potting soil for Dahlias

I used the bulk compost I buy from a local organic turkey farm but you can use basic bagged potting soil. Fill the container about a third to half full

potting soil in container for Dahlias

To aid in good drainage I added builders sand to the bulk compost. Depending on how loose your potting soil is determines if you need to do this step. Dahlias do not like to dry out but hate sitting in water. Good drainage is crucial!

I added a gallon of sand from the building supply to this container so adjust accordingly. (to measure a gallon I used one of the empty black pots)

You could also use perlite or rice hulls to help drainage but I like sand as it adds weight to the container. These are large dinner plate Dahlias that will get quite top heavy. Having added weight in the container aids in preventing them from possibly toppling over.

sand added to potting soil to plant dahlias in pots

Mix the sand in well and add a more potting soil until the container is nearly full.

There is much debate on whether to feed your Dahlias or not. I personally do. Start with a slow release fertilizer added to the soil as you plant.

During the rest of the season I use liquid fish fertilizer or this Seaweed fertilizer on most of my flowering plants in pots including the Dahlias.

I pre sprouted my Dahlias so I could take cuttings from them so that is why they are in pots instead of just tubers. See how I did that as it will show you how to plant the tubers straight into this tub instead of taking it from a pot.

Grow Dahlias in Pots

Islander Dahlia planted in a container

You can grow Dahlias in Pots. Easy directions for growing all types of dahlias in containers!

Prep Time 10 minutes
Active Time 10 minutes
Additional Time 10 minutes
Total Time 30 minutes

Materials

  • Well draining Containers and Pots
  • Potting soil
  • sand or perlite (optional)
  • Slow release fertilizer
  • Dahlia tubers

Tools

  • Small shovel
  • Gloves

Instructions

  1. Plant dahlias when soil is above 60 degrees
  2. Use pots or containers with at least 12 inches deep and wide for each dahlia tuber
  3. Make sure pots are well draining
  4. Potting soil also needs to be well draining. Add amendments to increase drainage like sand or perlite if needed.
  5. Add slow release general purpose fertilizer to potting soil, organic is best
  6. Plant dahlia tubers 2 to 4 inches deep and 12 inches or more apart
  7. Firm in gently to remove air pockets around tubers.
  8. Water in.
  9. Add more soil if needed to make sure tubers are 2 to 4 inches below soil
  10. Pinch dahlias to promote branching as they grow
  11. Cut off lowest 12 inches of leaves to promote good air circulation and prevent mildew
  12. Use slug bait if necessary to stop damage
  13. Feed dahlias throughout the Summer using a half strength fish emulsion fertilizer
  14. Cut flowers or deadhead regularly to promote more blooms
  15. Enjoy masses of bouquets!

Notes

There are many opinions on fertilizing Dahlias. Do some research, experiment and see what works for you.

Planting the Dahlias

Pop the dahlia plant out of the pot (if you pre sprouted your dahlias) and plant into your container.

replanting a potted dahlia into a larger container

If you did not pre sprout and have tubers to plant then place the tuber on top of the soil. Add more soil to cover them 2 to 4 inches deep.

placing 3 dahlias in pot

This container was large enough to hold 3 tubers and I planted them in a v shape so each had plenty of space to spread their roots as they grew. (if that confuses you then please watch the video at the end of this post and it will show you what I mean)

Firm the Dahlia tubers into the soil by pressing them down. We don’t want any air pockets around the tubers. Good soil contact is needed but be careful as you press them into the soil, you don’t’ want to snap off anything.

firm the Dahlia tubers into the soil to seat them well.

Water them in and add soil if you need too.

Dahlias planted in pots and containers in the garden

Mine bloom in August on until first hard frost, and though I must wait so long they are well worth it. By that time of the Summer so many other things are fading, the Dahlias fill the garden with color.

Islander Dahlia planted in a container
Islander Dahlia

If you wish to know more on Dahlias visit these articles:
Propagate Dahlias from Cuttings and How to Pinch Dahlias for More Blooms

Dahlia care

Dahlias like full sun but not searing temps. If you get some very hot days keep on top of watering as they can dry out too much. If your container is not too large and heavy you can move the Dahlias to a spot that gets some afternoon shade when temperatures soar.

Most larger dahlias will need to be staked. They especially need this support when in bloom, the large flowers can become quite heavy.

flat lay of an array of Dahlias grown in containers

Feeding Dahlias

I mentioned this before but it bears repeating. There is many opinions on feeding your Dahlia plants.

When planting if you add the slow release fertilizer it will feed for months as longs as the soil temps are above 70 degrees. Containers need some extra help since the constant watering flushes many nutrients away.

The main one being nitrogen. Most flowers need very little of the other two nutrients so by watering with the fish fertilizer once a week you are giving it the added nitrogen that can be lacking.

Dahlia Pests and Disease

Earwigs, slugs and cucumber beetles can be problematic with Dahlias. There are organic certified baits that work well for getting rid of slugs and earwigs, like this one, Sluggo. I only use it when I see signs of damage and not as a preventative. The cucumber beetles are still an ongoing struggle for me.

To prevent mildew don’t get the leaves wet and you can prune off the leaves of the lowest 12 inches of the plant. This will help air circulation about the plant.

Keep your Dahlias Blooming

This is one flower that the more you cut flowers from the more they produce. So enjoy cuttings buckets of bouquets for yourself or to brighten the day for someone else.

If you don’t cut flowers for bouquets then you will need to dead head spent blooms to keep your dahlias blooming. When cutting or deadheading, cut the flower back to the main stem.

Though in colder climes you have to dig and overwinter your tubers they are well worth the effort.

The hardest part of growing Dahlias is choosing which ones to grow. There are so many colors and varieties!

Dahlias grown in containers in a bouquet

Happy Dahlia growing in Pots!

Next year I will try raised beds with a hardware cloth lining to protect from voles and gophers. It may work even better!

Labyrinth dahlia with text overlay, Easily grow Dahlias in pots

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Rebecca Payne

Sunday 25th of October 2020

Great tips. Thank you for sharing.

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