Dahlias have been labeled as tricky to grow by some but by applying a few simple techniques, you can grow them successfully too!

Planting Location: Choose a location that gets full sun, this means at least 8 hours of direct sunlight, and well drained, fertile soil.

Tuber Timing: Planting tubers should be done after the threat of frost has passed and the ground temperature is at least 60 degrees Fahrenheit. Keep an eye for heavy rain in your upcoming weekly forecast. Saturated soil can rot a newly planted tuber. If rains are projected, hold off to plant a couple days after they end. For our farm, we usually plant around mid-May.

Tuber Planting: Dahlia varieties can get quite large so allow spacing of 12-24” depending on the plant size and help reduce the chance of disease that can be caused by tight growing conditions. Dig a hole 5-6” deep, back fill if necessary to this depth. BEFORE adding in the tuber, drive a tall stake approximately 12” deep and 8” away from your hole for support. *Important. If your variety is expected to grow taller than 3 feet, it is recommended to stake them. On our farm, winds are STRONG and we would absolutely lose many plants if we didn’t stake them. Next, lay your tuber horizontally in the hole with the eye facing upward. Back fill the hole with a few inches of soil mixed with compost if your bed wasn’t already amended with compost. Do NOT water unless your soil is very dry. If it is very dry, a light watering will be fine but only water once at this point. Now we put our patience pants on. LOL Once you begin to see green growth, you can continue to back fill the hole until filled completely. *Some growers will fill the hole completed the first time and this is okay too! We have found back filling shallowly at first helps the tuber get more warmth from the sun and grow a little quicker.

*If you receive your tubers before the timing is right to plant, it is recommended to store them as they came, in a cool (40-55 degree F) location at 70% humidity until planting. For many, this is a cool spot in your basement or garage. Do not allow them to freeze. If your tuber has begun to sprout and it’s too early to plant, simply remove the sprout and keep in storage. (Don’t worry, it will grow back!)

Dahlia Watering: Tubers already have the water and energy they need to begin growing. Other than the optional watering at planting due to dry soil, do not water tubers. Watering tubers can add to rot and potential death of your tuber. Once you see your tuber has sprouted, you can begin watering deeply 2-3 times per week depending on your soil and how well it retains water.

Dahlia Pinching: Yes, you read that right! Many growers will pinch the center stem to promote branching of their plants. Once your plant reaches approximately 12” tall or knee high for me, remove the center stem.

Hint: Different varieties take longer than others to grow. It can take 3-5 weeks to see sprouts but also earlier at times. Remember….keep your patience pants on!

Cutting Blooms: In my area, Zone 5b, dahlias bloom from late July to frost. If you want continuous blooms, it’s important to deadhead (remove spent blooms). Removing these will signal the plant to create more buds. If you prefer to cut blooms for bouquets, in the cool of the morning, cut stems deep (18” long) just above a node. (A node is where a leaf or stem would develop.) This may result in sacrificing some side buds and can make us all feel troubled but TRUST ME, you can do it! Remove most of the foliage to help the bloom hydrate easier and last longer. Blooms should be harvested when almost fully opened, but before back petals become wilted. Immediately place stems in a clean bucket with fresh water. Always use sheers, NOT scissors. Allow to sit in a cool, dark place for a few hours or overnight before arranging.

Hint: Dahlias often have one main bud, and two side buds. Pinching the side buds off while small can result in larger main blooms.

Dahlia Bouquet Care: Using tepid water, change water every 1-2 days. Do not just top it off. Dahlia blooms have a shorter vase life of approximately 5 days. Some varieties shorter or longer. Larger blooms tend to have a shorter vase life. Ball varieties tend to have a longer vase life.

Fall Care: With the first fall frost, dahlia plants expire. They cannot tolerate freezing temps. You have two choices. Some people prefer to grow dahlias as annuals. If this is you, cut back your plant and leave your tubers in the ground. The tubers will rot and compost into the soil. Some people prefer to grow the same varieties year after year. To do this, once the frost has killed the plant, cut the foliage down to about 6”. Allow the tubers to ‘cure’ in the ground for 2 weeks. Do NOT water. After they have cured, using a large garden fork or shovel. CAREFULLY dig up your tuber clumps. It is easy to sever tubers and break necks leaving them unusable. Some people wash their tubers off with water and store them. Others will shake off much of the dirt and store as is. Dahlia storage can be tricky. It is key to keep your temps 40-50 deg F and humidity approximately 90%. When these conditions are not met, dahlias will either freeze and turn to mush, mold and die, or shrivel and dry up leaving them unviable. Every dahlia grower has their ‘way’ to store tubers that works for their environment. I encourage you to trial a few ways to find out what works for you. Feel free to message me if you have questions about tuber storage.

GROWING IN CONTAINERS:

Not everyone has the space to allow growing dahlias in the ground. They can be grown in containers too with some extra care!

Choose a LARGE, light colored, container, at least 15” across.

If you’re growing a taller variety, be SURE to stake it at least once or use a TALL tomato cage.

It’s best to keep containers away from a wall or solid fence line, these things can increase temps and overheat & stress your plants.

Container grown dahlias tend to need more water and fertilizer.

A great resource for beginner dahlia growers, is Connie’s Dahlias, A Beginner’s Guide, by Connie Thompson.