Hello there! I am Eileen Tongson, a farmer-florist, and owner of FarmGal Flowers in Orlando, Florida, Zone 9b. I’m often asked, “You can grow flowers in Florida?” My answer to that question is a resounding “Yes!” and to the surprise of many, you can certainly grow dahlias too!
I first encountered dahlias on trips to the Pacific Northwest and later during my studies at Floret Flower Farm. I was mesmerized (you dahlia lovers know exactly what I mean!) and determined to bring these flowers home. I am also a Master Gardener and familiar with our local growing seasons and the intricacies of gardening here.
Eileen Tongson of FarmGal Flowers
THE GROWING SEASONS
We essentially have two primary growing seasons here, the Fall and the Spring. You can push some heat tolerant flowers through in the summer but it is very challenging with the intense heat, rain, and pests. Of course, dahlias are especially sensitive to those elements. So we begin planting dahlias in September and those usually start blooming in November/December. Fall planted dahlias can be cut back in early February and side dressed with more mushroom compost and organic granular flower fertilizer for more blooms in the Spring. Sometimes I receive orders of dahlias tubers early and we plant more tubers in early February for the Spring season. We can expect those to reach their peak in May.
PLANTING DAHLIAS
We are fortunate to have a mushroom farm nearby and grow all of our flowers in mushroom compost mixed with an organic granular flower fertilizer in raised beds. Growing in raised beds helps us reduce weeds and pests both of which can be relentless here. We have very little problems with slugs and snails, a common pest of dahlias, by growing dahlias in raised beds. Yes, they can climb but they are deterred by tall sides. Raised beds also tend to drain better which is very important here with all of the rain. Tubers are sensitive to rotting when there is too much water.
We dig a hole 6” deep for each dahlia tuber. I add a tablespoon of bone meal to the hole before placing the tuber in it. Bone meal adds phosphorus to the soil which stimulates root growth and later encourages the development of more blooms. I plant our tubers 12” apart. This is very important here to allow for good air circulation between plants. Our dahlias are susceptible to powdery mildew and good spacing helps prevent it. I also immediately stake the dahlia with an upside down 42” tomato cage (prongs cut off). This is secured to the ground with landscape pins.
I have found that the Ball type of dahlia seems to be the most prolific and have the best vase life here. Of course, we still grow the decorative types including dinnerplates.
FERTILIZATION
Once the dahlias have begun to sprout, we apply an organic foliar fertilizer of compost tea and seaweed once a week for a month and then once a month. As mentioned earlier, an organic granular flower fertilizer was added to the mushroom compost when our beds were prepped.
WATERING
Do not water your tubers until they have begun to sprout. Too much water may cause the tubers to rot. Once they have become established though, they require a good soak 2-3 times a week. Now we still receive a good amount of rain here in Central Florida in the Fall. So be mindful of this and do not water in addition to the rainfall. If your plants start to wilt during the heat of the day, mist them with water. This allows them to take in some moisture through their foliage.
PINCHING
As with most flowers, it is important to pinch your dahlias. Once the plant reaches about 12 inches, we snip off a third of that stem just above a pair of leaves. Do not wait too long for this step especially down here in the Fall. It is surprising how quickly the dahlia’s branches take off and grow (this is also why I place the stakes on early).
HARVESTING
As with all flowers, it is important to harvest your dahlias frequently to promote more blooms. It is especially important to harvest your blooms early or very late in the day here and right into a bucket of water with one CVBN tablet. It will take a while for your dahlias to rehydrate (if they able) if you harvest them during the intense heat of the day. Also, it is best to harvest your bloom before it is fully open to maximize vase life.
OVERSUMMERING (AKA Overwintering)
One of the advantages of growing dahlias here in 9b is we do not have to dig up our dahlias annually. At the end of the spring season, we cut the foliage back and cover with pine straw mulch. Then in the Fall, we add compost and fertilizers and the growing process begins again. They return bigger and better! I try to dig up our tubers every 2-3 years (depending on the size and quantity that type of dahlias produces). Of course, if you want to increase your stock of tubers, you can always dig them up more often.
TUBER STORAGE
The tricky thing about planting dahlias in hot climates is it can be difficult to obtain tubers when it is ideal to plant them here. Most wholesalers and dahlia farms ship them later in the spring although I have found a few smaller farms that will ship early enough for us. So what to do? When I receive my tubers in April or May, I store them in vermiculite and hold them in my cooler until the Fall planting season. It is hard to be that patient but trust me, you will be rewarded with beautiful blooms later in the year.
I hope these tips help other hot climate gardeners and flower farmers grow an abundance of dahlias! I highly encourage you to bring these exquisite flowers to your gardens!