The Editor's Tutorial

.Propagation

   Cuttings can be taken either directly from the tuber in the form of surplus stems (basal cuttings), or as side shoots of the main stem (stem cuttings).  The earlier in the season they are taken the longer they have to develop  worthwhile sized tubers.
   It must be remembered that the aim is to produce a tuber and not a flowering plant, for this reason the growing tip is pinched out once the cutting has rooted and the plant restricted to a relatively small pot.   

Fred Martin

This is what we are out to achieve,  large plump tubers that will give worthwhile results the following season.  Do not be concerned that the shape may be irregular, unlike tubers produced from seed those developed from cuttings will often appear somewhat misshapen.

The compost I am using is SCOTTS Levington F2 premixed with sufficient water to make it cling together.

Additional water, then silver sand is poured into a hole in the centre of the compost of each 3½" 9cm pot.  I believe that the sand encourages root action and helps tuber development.

This is a newly acquired variety, to build up stocks I am going to take off as many cuttings as possible this year.  The strongest stem will be left and the others removed for basal cuttings when about 4" 10cm. in height. Later in the season as many stem cuttings as possible will also be taken.

Basal Cuttings are taken straight off the tuber and may well produce the best new stock for next year because they can be taken early in the season.  They can be removed with a sharp knife but I find it easier to just pull them free.  With any luck a few roots will also be included.  The wound on the tuber is dressed with a little green sulphur and left uncovered for a few days.

Stem Cuttings these are really potential flowering side shoots and removing them will affect the final appearance of the plant, I would suggest however that priority is given to build up stocks of any newly acquired variety. The shoots form at the base of a leaf axis.  

Take care not to cut into the main stem or leaf but to include the eye which is protected by a bract.  The knife, or better still  scalpel, is dipped in methylated spirits after each cut to sterilize the blade.

Once the cutting has been severed it is potted individually in a 3½" 9cm pot, rooting powder is not necessary.

After about 4 weeks in a heated propagator placed in a well shaded spot (under the staging is ideal) the cuttings should be rooted and the propagator top can be removed.  During this whole period it is necessary to inspect regularly as any rotting leaves will quickly spread through the whole tray.
After a few more weeks the cuttings will be ready for potting on.  I use Levington M3 which is stronger than the F2 used to strike them in. The growing tips are pinched out and all buds removed.

A large plant can be grown from early cuttings, but this is not the aim, the idea is to produce a worthwhile tuber for the following season and for this reason the developing plant should be restricted to a relatively small pot.
 Towards the end of the season my cuttings are placed into a heated sandbed, on top of the sharp sand is a layer of soil less compost and the pots are partially buried into this. A soil temperature of 55ºf. 12ºc is set.  This will keep the plants in green leaf until about late November.  During this time watering is maintained.