DG Site Updates: Proposal: Carnations (Dianthus caryophyllus) Forum, 1 by Michael_Ronayne

Michael_Ronayne wrote:
I have been purchasing inexpensive cut carnations with the objective of learning how to propagate Carnations from cuttings. Using stock from the flower-trade has the disadvantage of not knowing the age of the cuttings with which you are working; and, given that there is no longer a viable Carnation industry in the United States most of the cut Carnation sold in the United States are from abroad. In the books of Carnation horticulture the selection choice fresh stock is emphasized. My initial efforts can only be described as disasters but I did learn from them. From my current effort I have a number of cuttings which appear to be viable and producing new growth but it will be a few more weeks before I asses the results. I have four plants from my previous effort which are growing slowly.

The cuttings are growing in 2.5”x2.5”x3.5” plastic pots which are contained in a nested pair of standard “1020 Trays”. The inner tray is perforated so that water will drain from the inner tray into the outer tray. If the cuttings are overwater the inner tray can be lifter to drain excess water. As recommended by Jojo Sigurgeirson, I am using cactus potting soil to root the cuttings, the advantage being that the cuttings don’t have to transplanted as early, if artificial rooting media were used. For the first two weeks a large transparent plastic bag was used to maintain humidity but this setup is proving to be awkward and the use of a high humidity dome for 1020 Trays is being investigated. After the plastic bag is removed the cutting as misted every time they are inspected and the 1020 Trays inspected to verify that water is not accumulating. The attached photograph shows a tray with growing Carnation cuttings.

I am using two node cuttings with about 0.5” of extra stem at the top and bottom of the cuttings. The bottom node is buried about 2” into the cactus potting soil. The purpose of the bottom node is to support the formation of roots but I have noticed that the bottom node can also send up new shoots.

The biggest problem with rooting carnations is overwatering which rots the stem and lower node. The second hurdle is humidity control. I am continuing to propagate Carnation cuttings with the objective of having enough plants to put out this coming spring,

In reviewing my successes and failures I am going to change the protocols I use for the next rounds of tests, which include the following.

1. Use of 7” high humidity domes for 1020 Trays.
2. Use of a two node cuttings with 2.5” of stem at the bottom and the lower node at soil level.
3. Use of a one node cutting with 2.5” of stem at the bottom and the single node at soil level.

In attempting to propagate cut Carnations, one of the problems is finding useful sections from which to take a two node cutting. If Carnations can be propagated from a single node cutting, that would be a significant advantage to the home horticulturist. In addition, cut Carnations tend to have longer distances between nodes which means that clearance inside a humidity chamber becomes an issue. Remember that most of the instructions for propagating Carnations were designed for commercial greenhouses one hundred years ago

I would be very interested in anyone’s experience with prorogating Carnations or other Dianthus species from cuttings. As a secondary area of inquiry, any non-seed propagation experiences would be of interest. I am interested in both successes and failures as I want to understand what will and will not work for the home gardener.

Mike