Propagation by Sprout Cuttings:
Discovering What Works

Page 4

It takes three to four weeks for the cuttings to develop visible roots. If you use a soilless growing medium in a two inch pot, the roots typically grow out of the holes in the bottom of the pot. The picture at the right illustrates the two types of root formations I have observed using Oasis cutting cubes. The plant on the left has produced roots at the point where the stem meets the planting medium (Oasis cube) and represents about 20% of rooted cuttings thus far. Its roots are not yet long enough for transplanting to a pot. Up to this point, the plant on the right is more typical. Its roots have emerged from the planting medium and the plant is ready to be transplanted to a pot.

Transplanting the fragile rooted cutting requires considerable care. I use a soilless potting medium.

4 qts. Spaghnum Peat Moss
2 qts. Vermiculite
2 qts. Perlite
1 tbs. Dolomitic Limestone

The dolomitic limestone raises the pH to about 6.5.

I place the Oasis cube with the rooted cutting in the potting medium so the cube is slightly covered and the node of the first two leaves is slightly above the top of the pot as shown at the right. During this process I distribute 1/2 tsp. of Osmocote 14-14-14 throughout the top half of the potting medium. I water the plant with a solution of Peters Soluble Trace Element Mix (STEM). The strength of this solution is 1/4 tsp. STEM per 25 gallons of water. This one-time feeding of Osmocote and STEM should last until planting outdoors. The STEM is necessary because this particular Osmocote contains no trace elements.

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Since the cuttings have been under domes and artificial light and kept at 68 to 70 degrees fahrenheit, it will be necessary to harden the plants before moving them directly to the greenhouse or cold frame. The plants must be watered as needed--moist, not wet. Once watered, do not water again until the top 3/4 inch of soil is dry--then water again.

The plant pictured on the right is 10 weeks old--that is 10 weeks from the time the cutting was taken.

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As of March 10, 1998, I have taken 204 sprout cuttings. Three cuttings died, two showed virus symptoms and were destroyed along with the mother tuber, and one was dropped and broken for a survival rate of 97.1 percent.

Given Gary Miner's comments, I am not able to assert that the rather dramatic increase in the survival rate (from 70% to 97%) was achieved as a result of preventing contamination. If all goes well, next year I plan to devise an experiment to determine the importance of the "clean cut/bad cut" variable.
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