The Two Biggest Mistakes Beginning Dahlia Growers Make

You spent all winter stalking websites for that elusive tuber and drooling over the gorgeous pictures. Then spring came and you planted your tubers but now it’s August and it doesn’t seem to be working out like you dreamed right?

It’s pretty common to feel like you missed the mark when trying something new. For some reason, we have this expectation of getting it perfect the first time. This is totally unreasonable and if we are honest with ourselves, we know we shouldn’t be beating ourselves up over it! So let’s just take a moment and acknowledge that we are beginners and first timers make mistakes. And that’s perfectly OK!

When it comes to dahlias there are two mistakes that everybody makes. And full disclosure here- it took me more than a year or two to really master these two things. (Translation: give yourself time and grace)

Mistake #1: Support! Dahlias just like people need support. Beginners often forget to support or think about it too late. I was always in the too late crowd.

There are different methods: If you are growing a small number, then stakes or tomato cages work well. If you are growing for production then I recommend horizontal netting or using the Florida weave method (Google this if you don’t know what it is- you need to see a video to understand it). If you grow in a 3-4’ wide bed- then go the netting route. Stakes should be 5-6’ apart down the row and make sure they are sturdy. I recommend rebar or fiberglass or very thick wood stakes. I’m not a fan of wood stakes in my heavy clay soil- they just rot by the end of the season. I use all rebar. Also make sure you are capping that rebar somehow so you don’t poke an eye out during harvest.

If you grow 1-2 plants wide in long rows, then the Florida weave works well. Tying dahlias in on wide rows has never worked well for me - too much room for them to move around. But if you grow long rows, 1-2 plants wide then tying dahlias works great! You can also use netting on skinny rows too- you may just have to cut the width of the netting to size.

Last thing about support— You need to do it pre-emptively. If you are using a stake or tomato cage, then install it after planting your tuber. If you wait until later, you may stab your tubers as they are growing/multiplying under the ground. For netting, I put it on after I pinch my dahlias. It’s easier to pinch if the netting is not in the way.

Mistake #2- Food and Water! Dahlias are hungry plants and beginners don’t realize how hungry they are— think teenagers on a growth spurt kind of hungry! They need lots of water once they begin setting buds. Make sure your soil is draining well but daily water is necessary if you live in a hot climate for sure.

Weekly feeding until about the end of September if you want a regular supply of blooms- especially if you are growing for production. You can foliage feed, fertigate if you have an injector, granular, or liquid poured at the base of the plant. I’ve used all of the above except the fertigator (One Day, One Very Happy Day!)

Granular feeds are easy and I used to use them a lot before I began planting in fabric. The important part about granular feeding is that you need to water it in. I got to be a pro at getting my granular feed spread right before a tropical storm would come through. Granular is nice too because it can be time-released depending on what you use so it’s good for those who want to spend a bit less time on feeding their plants.

Foliar feeding is definitely one of the most common and also easy to do. You can put it in a bottle and spray if you are doing a few plants. Or get a backpack sprayer— this is what I recommend if you grow for production. I love mine. I use the My 4 Sons brand- Battery powered, reasonable price, charge lasts forever!

Liquid applications work well- although probably better on a small scale. Large scale liquid applications would need to go through fertigation— One day I’ll have one!

So what to feed with? Ideally you took a soil sample before planting and amended accordingly. This gives you a base from which to start. But when is life ever ideal?

In general, dahlias need a complete fertilizer when they are growing (before bud formation) and a fertilizer high in phosphorus and potassium when they begin to set buds. I really like Neptune’s Harvest brand- they work well and are easy to find. Also Alaska Morbloom 0-10-10 is really good for the bud/flowering stage. Most fertilizers that work well for roses or tomatoes are suitable for dahlias too. They have similar feeding needs.

Most likely if your dreams are not materializing, they just need a little TLC. Go stake those plants this weekend. Make sure they are getting plenty of water and give them a nice meal. They’ll reward you with gorgeous blooms as the weather begins to cool this Fall!

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