How to Plant Dahlia Tubers Year After Year

Rather than buying a new plant every year, save money by protecting your dahlia tubers over the winter. Check out this article to learn how to care for your dahlias.

Dahlia Tubers

Q: I bought a variety of summer flowering bulbs this last season and planted them, with beautiful results. I truly enjoy the beauty of these flowers, but do I have to dig them up every year? If so, how do you care for the tubers, and how far do you cut these gems back after you dig them up?

A: This entire set of instructions can be used to store summer-blooming rhizomes, tubers and bulb-type crops such as calla lily, canna, dahlia, gladiola and many others.

If you live in an area of the Deep South that doesn't get a frost, you don't have to dig them up. If the temperature only gets below freezing for a few days at a time, you can leave them in the ground, but you will have to protect the plant from frost. If the top of the plant gets frosted, it will turn black and die, but if the tuber was protected, it will send up new sprouts in about a week. If you live in any kind of cold climate, you have to either dig them up, or let them die in the cold and plant new ones next spring. They can be left in the ground from USDA Hardiness Zone 8 and farther south.

Dahlia tubers differ a little from the others because they are only mature enough to dig up if they have eyes sprouting on the tubers. Either cutting the stalks down or letting frost kill the tops will start the process. New eyes start to form and eventually sprout. It takes anywhere from just a few days to more than a week to get the eyes to form. They look a lot like the eyes on a potato. You will see raised bumps that begin turning color. If you have lots of dahlias, you can cut them back in groups, so you don't have too many to do at once. If you have a lot of them and a frost comes, you can protect some of them with straw to delay their need to be dug up.

Stake out the base of each summer-blooming plant. Use labels if you want to keep track of the variety or color. Cut off the live or frosted stalks from 2 to 4 inches above the soil, and then wait a week. Scrape the mulch at least a foot away from the plant. Use a shovel to cut a circle of roots a foot away all the way around. As you pry up with the shovel, lift the plant from the hole. Don't break off the individual tubers. They can break easily, so be careful. A tuber that breaks off without any eyes will not be any good.

Wash all the dirt off from the tubers or rhizomes. Use a gentle spray from the hose because a hard spray will damage the skin and even gouge the tuber. Soaking them in a bucket for an hour can loosen the soil, making them easy to wash off.

You can write the flower variety and color on the bulb itself or on a label that is attached to the bulb with string or rubber bands. Or you can just label the bag they go into for storage. The bag, box or a room they are stored in must be kept dark so they don't begin to sprout.

They need to be stored in a temperature range of between 35 and 50 degrees F. Check on them a couple of times during the winter to see whether they are beginning to get moldy. If they are, add more fungicide. Check to see whether they are looking shriveled. If so, add a tiny bit of water to the bag.

Too much water promotes mold, and too little causes them to dry out.
Wait until spring to divide them. This will allow the mother tuber and the tubers without eyes to help keep the other tubers from drying out during storage. In the spring, it will be easier to see which ones have good developing eyes and sprouts. If they are cut in the spring, let the cut end heal over for a day or two before planting, or dust with a fungicide and then plant.

In the spring, you can begin planting them into pots of potting soil about a month before your area's last frost date. This will give you a head start. If you have a greenhouse, you can begin even sooner.

Dahlia Tubers


Email questions to Jeff Rugg at [email protected]. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at

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