{"id":27549,"date":"2026-09-22T10:22:48","date_gmt":"2026-09-22T17:22:48","guid":{"rendered":"https:\/\/extension.wsu.edu\/yakima\/?p=27549"},"modified":"2026-09-22T10:29:15","modified_gmt":"2026-09-22T17:29:15","slug":"fall-dahlia-care","status":"publish","type":"post","link":"https:\/\/extension.wsu.edu\/yakima\/2026\/09\/22\/fall-dahlia-care\/","title":{"rendered":"Fall Dahlia Care"},"content":{"rendered":"\n

Fall Dahlia Care<\/h1>\n\n\n\n

by Carol Barany, <\/strong>Yakima Master Gardener<\/h2>\n\n\n\n

Mid-September\u2019s soaking rains washed the dust off my garden and gave it a sparkle and freshness I haven\u2019t seen since spring.  I have to remind myself that the average first frost date at the Yakima airport weather station is October 3. Two weeks later, the City of Yakima\u2019s irrigation season closes, marking another milestone on the march to the season\u2019s end. <\/p>\n\n\n\n

As the cold weather approaches, my mind is on the inevitable end-of-season care my beloved dahlias depend on.  <\/p>\n\n\n\n

If it\u2019s important to know one dahlia from another next spring, check their ID tags now for accuracy. Once dahlia plants are cut down by frost, they all look the same.  Imagine collapsed heaps of mushy grey stems.  <\/p>\n\n\n\n

Most dahlia growers can skip this step because they have a successful naming system already in place.  I envy you.  Anyone who has ever received a dahlia tuber from me can testify there\u2019s a 50% chance that the tuber is actually the variety I think it is. <\/p>\n\n\n\n

Hope springs eternal.  <\/p>\n\n\n\n

While my dahlias are still blooming, I\u2019ll tie a length of plastic flagging tape to the base of each clump and record the variety name.  When I dig the clumps, they\u2019ll already have an ID label attached. <\/p>\n\n\n\n

For as long as I\u2019ve grown dahlias, I\u2019ve waited a week or two after a killing frost to dig. It turns out that it\u2019s another gardening myth that frost is necessary for successful winter storage. Gardeners in warm climates that never get frost dig and divide their dahlias just fine.  <\/p>\n\n\n\n

That\u2019s because as the days grow shorter at the summer solstice, it\u2019s the increasingly longer nights that trigger dahlias into tuber development.  You can dig tubers after they\u2019ve been growing for a minimum of 135 days.  There is nothing wrong with waiting for frost, but it\u2019s not a requirement.<\/p>\n\n\n\n

Dahlias can be left in the ground to overwinter in USDA Zones 8 and warmer. In colder climates, dahlia clumps must be lifted and stored indoors to prevent them from freezing.  Many Zone 7 Yakima gardeners are now successfully leaving their dahlias to overwinter   in their garden beds with some extra protection.  <\/p>\n\n\n\n

Nothing is more sacred to an experienced dahlia grower than their own method of winter storage. If you\u2019ve already found it, today\u2019s column is not for you.  But if you have the urge to experiment, there is a relatively new method of storage you may want to try.<\/p>\n\n\n\n

The goal of any storage method is to preserve the tubers as closely as possible to the condition they were in when they were dug in the fall. Using plastic wrap eliminates the use of any other storage mediums such as peat moss, vermiculite, sand, wood shavings or cedar chips. An added bonus is that much less storage space is needed <\/p>\n\n\n\n

Research from the Michigan Dahlia Society reported on this method to the American Dahlia Society in 2001.  The Michigan growers admitted to having concerns initially.  It\u2019s counterintuitive that wrapping a tuber tightly in plastic can prevent rot and other storage issues.  Taking no chances, the first year they packed 25% of their yearly harvest of  a whooping 1,200 – 1,500 tubers in plastic wrap and 75% in vermiculite, their traditional storage medium. The results were outstanding for the plastic wrapped tubers. Each successive year the Michigan growers stored 25% more in plastic wrap until 100% of their tubers were stored this way with no loss from shriveling or drying. <\/p>\n\n\n\n

They feel that the plastic wrap holds in moisture and the plastic dividing the tubers prevents rot from infecting multiple tubers. This storage method also seems to encourage tubers to sprout a bit earlier than usual.<\/p>\n\n\n\n

Yakima Master Gardeners have used this method to overwinter tubers from the Ahtanum Garden for the last 2 years and also report an almost 100% success rate. <\/p>\n\n\n\n

A dahlia tuber must have a body, unbroken neck, and eye in order to grow and reproduce. The body holds the energy and nutrients needed to produce next year’s plant, the eye turns into the sprout, and the unbroken neck connects these two parts. Compost the tuber if any of these parts are missing because it will not grow. <\/p>\n\n\n\n

Once the viable individual tubers have been washed, some growers apply a fungicide before drying and wrapping. There are suggested products listed on the American Dahlia Society website.  <\/p>\n\n\n\n

Here in Yakima, Master Gardeners do not use any fungicides as long as the tubers are clean and dry before wrapping. <\/p>\n\n\n\n

Place a dahlia tuber at one end of a 20 inch sheet of plastic wrap and roll the wrap around it a few times. You can add additional tubers of the same variety, one at a time, rolling as you go. Each tuber should be fully enclosed in plastic and separated from the next tuber by a layer of plastic. Once you have wrapped   5-7 tubers, fold in the sides of the plastic wrap as you would a burrito. Fasten the bundle with a cultivar ID label.<\/p>\n\n\n\n

If you bundle several varieties together, write the cultivar name directly on the tuber with a permanent garden marker.<\/p>\n\n\n\n

Place the bundles in a cool, dark box or bin where the temperature stays consistently between 40 and 50 degrees F.<\/p>\n\n\n\n

For guidance and tips on digging and dividing, visit the American Dahlia Society website, and then dream of spring. <\/p>\n","protected":false},"excerpt":{"rendered":"

Fall Dahlia Care by Carol Barany, Yakima Master Gardener Mid-September\u2019s soaking rains washed the dust off my garden and gave it a sparkle and freshness I haven\u2019t seen since spring.  […]<\/p>\n","protected":false},"author":210,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_wsuwp_accessibility_report":null,"_external_link":""},"categories":[14],"tags":[65],"_links":{"self":[{"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/posts\/27549"}],"collection":[{"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/users\/210"}],"replies":[{"embeddable":true,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/comments?post=27549"}],"version-history":[{"count":3,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/posts\/27549\/revisions"}],"predecessor-version":[{"id":27552,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/posts\/27549\/revisions\/27552"}],"wp:attachment":[{"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/media?parent=27549"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/categories?post=27549"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/extension.wsu.edu\/yakima\/wp-json\/wp\/v2\/tags?post=27549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}