Some growers like to get a head start for earlier blooms, or they receive them when their growing zone could still receive a light frost. I prefer not to have them potted up for more than a couple weeks, unless I am trying to increase my stock of a variety. Be sure to label with pencil the names of each variety you pot up early so that your garden planning stays organized. Spritz with water if you feel the medium is too dry.

Dahlia tubers started indoors must be properly ‘hardened off’ by taking them outside (in a sheltered location) for about a week. I start at with 1-2 hours and work up to full-time outdoors as weather allows.

Dahlias can be planted outdoors after your location has NO chance of frost. Be sure the soil has warmed enough for them to grow. Some people use the blooming of local lilacs to indicate the time is right. You can figure out the date of your last frost by looking up your zip code and last frost dates of the past or consulting an almanac. I plant at the same time as my tomatoes and peppers.

While dahlias can grow in the shade, they will not thrive or bloom well with less than 6 hours of sunlight. Choose a location with as much sun and as little wind as possible. The more sun, the sturdier and more floriferous your plant will be. If your summer gets very hot, choose a location where the plants may receive afternoon shade. Some commercial growers use shade cloth to protect their plants later in the hot season.

I plant my tubers 4” down. In windy locations you may plant up to 6” deep to help with stability. You may place the tuber horizontally, with the eyes facing up. Sometimes, for varieties with ‘messy’ clumps I grow them vertically (to make division easier). Cover them with soil, but do not water. Before they form roots and sprouts, the tubers may rot if they are too wet.

While you may plant dahlia tubers as close as 12” for tuber production and space saving, they really need a full 18-24” to perform their best. I plant mine at 18” and stake them at the time of planting so that I don’t puncture tubers later.

While I believe dahlias thrive best on drip irrigation, regular hand watering will do just fine. Just don’t start until you have decent sized sprouts. Then begin weekly watering. Twice a week during summer should be enough water, but they DO love water. Consistent and frequent is best. If you live somewhere hot, water more.

I fertilize with bunny droppings when I plant, sometimes bone meal. Refer to your soil test to make these decisions. You may also use a weekly, weak (diluted) fertilizer such as fish emulsion or (my favorite) compost tea as a foliar feed.

This is how growers get those luscious, bushy plants. When your dahlia is 12” tall or has 3-4 sets of leaves you may break off the central growing tip (which you can propagate). Be sure to break it off cleanly above the top set of leaves and not where the stem could be hollow. This technique creates more branches and therefore more flowers, but it does set blooms back by about a week.

This is especially important if growing in containers. If you need support, be sure to add it when you plant, so that you do not unintentionally stab a tuber. Tomato cages, originally designed for dahlias, work great. I have also tied them to wooden stakes and used T posts with a ‘Florida weave’ technique for growing many plants in a straight row.

Especially important for those giant-sized blooms, disbudding is when you break off the 2 side buds of each set. This puts all the energy into one main bloom. Buds usually come in sets of 3, this technique is not necessary if you would just like more blooms in a garden setting. Disbudding is important to cut flower growers and is a very labor-intensive daily core.

Cut off ‘spent’ flowers to encourage more blooms. I do this at least weekly, unless you are trying to collect seeds. Growing dahlias for seed will give you far less flowers, as seeds require a LOT from your plant.

I do not grow in containers unless I am quarantining a new variety. It is much harder to prevent tuber failure in containers. They require a large pot, very good drainage, and good potting soil mixed with sand. Tuber clumps will still form in containers but may be crowded and messy. Plant deep and use a good support/stake. I tie mine up frequently as they gain height. Or use a cage.

If you live in zones 7 or lower, you will need to dig your tubers for storage. Or, if they were grown in a container, you may bring the whole pot in for winter. Wait until after a killing frost to dig. I wait even longer, for there is a belief (I haven’t kept track of accuracy) that you will see eyes better if that have more time in the ground. Sometimes the weather does not allow this. Allow them to cure somewhere for a couple days before storing. Keep them somewhere cool and dry, with high humidity. There are as many storing methods as there are dahlia growers, so please experiment to find what works best for you.