7 Growing Tips for County Fair Prize-Winning Dahlias

Dahlias are all the rage these days, and it’s no surprise why. They have some of the most wonderful, spectacular blooms around, and once you get the hang of it, they’re not difficult to grow. Of course, that doesn’t mean it won’t take some effort, but they are sturdy plants, and with the right care, they produce lots of big (or small), beautiful flowers. 

The Dahlia genus is a large and varied one. With 42 accepted species and more than 50,000 varieties, you can find them in nearly every color and quite a number of flower forms. Once you get the dahlia bug, you’ll find out how addictive these plants can be. 

Whether you’re planning to take your flowers to the county fair this year or just want blooms that are worthy of an award, we can help. I’ve got some tips for you that will have your dahlias producing the most spectacular, prize-worthy flowers in the neighborhood, and maybe even the whole county. Let’s dig in!

Choose Healthy Tubers

First and foremost, if you want stunning dahlias, you need to have healthy tubers. You can grow them from seeds, but since seeds don’t always breed true, it’s best to start with tubers if you want a specific variety. Tubers are their bulbous, energy-storing roots that form underground. 

If you’re ordering your tubers online, it’s tough to know what you’re getting. I recommend ordering from a trusted source with a good reputation. This way, you know you have a good chance of getting viable tubers, and should be able to return any that arrived damaged or non-viable.

A healthy tuber should be plump and firm to the touch. Any mushy parts are rotten, and you should dispose of them. If they are too dry, they will wrinkle and shrivel. These are not healthy either. They’re dried out and unlikely to grow. 

The second thing to look for is viable eyes. Think about a potato that’s been in the pantry for too long. They start to sprout little eyes that will ultimately turn into stems. Dahlias grow the same way. 

Look at the top of the tuber, at the stem end, where it connects to others. Look for small green, white, or purple growth points. This is what makes the tuber viable. Choose tubers with large, healthy-looking eyes. 

Plant in Rich Soil and Full Sun

Dahlias are demanding plants that require ample sunlight. It’s true that if you plant them in mediocre soil, they will probably grow, but they’re not likely to reach their full, glorious potential. 

Select a spot that receives at least six hours of sunlight daily. Some afternoon shade is fine, and in warm climates, it’s preferable. Six to eight hours of sun, early in the day, is ideal.

Amend the soil with nutrient-rich compost or manure to increase its nutrient content. It’s always a good idea to run a soil test in the spring to determine if your soil is lacking in any macro- or micro-nutrients. Your soil should be loose, well-draining, rich, and able to hold some moisture. 

Give Plenty of Water

When it comes to watering, dahlias like a lot of it. They just don’t tolerate consistently soggy soil. Those tubers will rot if the soil doesn’t have proper drainage. They have hollow stems that they use to transport ample water to their flowers.

Water your plants deeply and frequently. Aim to give them about one inch of water per week. If you’re getting a fair amount of rain, you can probably skip watering for a day or two. During the summer heat, you may need to water daily. 

Dahlias’ leaves will let you know when they are thirsty by wilting. Don’t let them stay like this, or you’ll put stress on the plant, and it will take longer to bloom. Water in the morning so they have plenty of time to absorb it before it evaporates. Never water in the evening, as they are susceptible to powdery mildew. 

Fertilize

Whether they’re prize-winning varieties or humble backyard cuties, dahlias are moderate to heavy feeders. They benefit from regular fertilizing, and their flowers will be stronger and more prolific as a result. In containers, they will require even more frequent applications. 

It’s a great idea to mix in some organic materials at planting time. I mentioned adding compost or manure at planting time. These break down over time, supplying the plants with a steady supply of nutrients. 

If you truly want to step up your game and see incredible blooms, apply additional fertilizer every three to four weeks (two to three weeks for container plants). Use a formula that is higher in phosphorus and potassium, and lower in nitrogen. Nitrogen will boost green growth, while the other two nutrients will be applied to root and flower production and integrity. 

A formula with a ratio of 10-20-20, or 5-10-10, is great for dahlias. Look for one of these or something similar. Most bloom-boosting fertilizers have a similar composition. 

Pinch and Strip

Pinching and stripping sounds a bit unpleasant, but I promise that doing these two things will result in stronger dahlia plants and more prize-worthy blooms. You’ll improve the airflow while also encouraging branching. More branching means more flowers.

Pinching will come first. If you’re not familiar with this practice, pinching is the process of removing the top set of leaves from a branching plant to encourage that process. By pinching off those leaves, the plant redirects energy into the lower buds, which then branch out. 

Pinching promotes bushier growth and strong, sturdy stems. However, it can also lead to crowded foliage that prevents air from circulating. This is where stripping comes into the picture. 

Stripping, also called debranching, is the process of removing the bottom leaves from your stems. This makes a clearer path for air to circulate around the base of the plant. Wait until your plants are about halfway to their mature height, and then strip off the lower leaves. 

Stripping tells the plant to redirect energy once again, this time to producing flowers instead of supporting that foliage. It also helps prevent powdery mildew, a common issue. 

Protect Buds

Prize-winning dahlia flowers are large, soft, and enticing to insects. They are even edible for humans, so you can be certain there are a number of pests that come for them. As such, it is essential to protect them to ensure healthy flowers. 

Earwigs are the most common and troublesome pests of dahlias. You may know them as pincher bugs. They look positively terrifying with their large pincers at the front of their body. I’ve never been pinched by one, but I imagine it must be terrible. 

Other fans of these flowers include slugs and snails, aphids, and caterpillars. The most concerning damage done by any of these is to the blooms themselves. The plants are relatively sturdy, but the flowers are delicate. Many of these pests will eat large, unsightly holes in your petals. 

The most effective prevention to keep insects from wrecking your prize-winning flowers is physical protection. I never advocate for spraying pesticides on flowers. This is harmful to beneficial insects.

The best way I’ve found to keep pests off my dahlias is with individual organza bags. The type of bags that you might see used for wedding favors. Slip a bag over the bud when it first begins to swell and draw the string snugly, but not too tightly, around the stem. This will ensure undisturbed blooms without unsightly holes. 

Cut at the Right Time

When it comes to cutting, make sure you wait long enough, or you’ll end up sadly disappointed. There are some flowers that we cut while they are in the bud stage. That is, before they open. These flowers continue to open after cutting them, revealing their beauty after several days to a week in a vase.

Dahlias, sadly, are not one of these. If you cut a dahlia bloom too soon, it won’t open, and you’re stuck with a half-opened bud without the prize-worthy displays you’re seeking. This means that you need to wait until they are nearly fully opened before cutting them. 

The most unfortunate aspect of these plants is their short vase life. And, it is a result of this specific factor. Because you have to wait for them to open on the plant before cutting, they are already halfway to wilting by the time you get them in water. These flowers last, at most, one week in a vase. 

To extend their life as much as possible, ensure that you place them in water immediately after cutting. Those empty stems are thirsty, so the first 24 hours after cutting them, they will suck up a lot of water. Don’t let them dry out.