Digging, Dividing, and Storing Dahlia Tubers Page 1

by Ben Lawrence

At one time, dahlia tubers were quite expensive. Today, however, the price for tubers at local Society tuber sales is such that many people choose to buy new tubers each year rather than digging and storing their tubers. At the same time, others write or call requesting information about digging and storing tubers. This page is prepared for the first time dahlia grower who intends to dig and store the tubers produced.

When should dahlia tubers be dug?

One consideration pertains to the tubers attaining maturity. In some parts of the country, tubers can be left in the ground for a very long time and reach maturity with little difficulty. In others, very hard freezes that can destroy the tubers require that the tubers be removed before any such hard freeze and the question of maturity becomes a secondary matter. You must dig the tubers prior to a hard freeze or lose them with one exception. Some very industrious persons have been known to mulch their dahlia beds with six inches of straw to protect against freezing and then dig the during a later warm spell. If you raise a lot of dahlias, that can be a substantial chore.

Some people advise that the plants should be cut down right after the first killing frost (the majority of the plant is blackened by the frost). But in some parts of the country a killing frost may be accompanied by a hard freeze. Obviously, deciding when to start the process of digging your tubers is very dependent on local conditions and you should consult with dahlia enthusiasts in your area in making those decisions.

Another consideration pertains to the visibility of "eyes" on the tubers. Once the majority of the dahlia plant is blackened by a frost or when a plant is physically cut down leaving a four to six inch stem, its tubers are stimulated to produce sprouts and develop a new plant. An "eye" is a precursor to a sprout. Eyes begin to swell quickly, typically within 4 to 8 days after the plant is destroyed by frost or being cut down. If you wish to divide the tubers when eyes are optimally visible, you should dig and divide the tubers in that 4 to 8 day window. Earlier, the eyes will be less pronounced--later, the eyes will turn to sprouts. And of course, these timing guidelines are average, not precise. In some cases, for example, I have seen plants still blooming that commence producing sprouts as though they have their own internal clock or respond to stimuli that we do not understand.

Cut Down the Plants.

At the end of the season, marked by a killing frost or determined by your fall plans, and when you plan to dig the tubers, cut the dahlia plants down, leaving a four to six inch stem stub.



Remove Dahlia Plant Paraphernalia.

Support cages, stakes, and irrigation equipment should be removed. They will interfere with the digging process.



Remove Mulch?

If the surface mulch is to be mixed into the soil, it should be left. Otherwise it should be removed to avoid mixing it into the soil during the digging process or later tilling.

Digging with a fork spade.

Place the fork approximately one foot from the stem stub and insert it deep into the soil--at least eight inches. Then gently pry back on the fork to loosen the soil. Repeat this action to totally encircle the stem stub and loose the soil. At the last insertion, prying back on the fork should lift the stem stub and the clump of dirt. Taking hold of the stem stub, gently lift while prying back on the fork until the clump comes free. Lift gently on the clump with one hand, letting it partially rest on the soil. Using the other hand, carefully remove the soil from the tuber clump. This must be done gently. Many tubers have rather small necks and can be broken or cracked while loosening the soil or carrying the clump to another location. A tuber with a cracked or broken neck will not grow.


Continued on next page.

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