extra emphasis on humidity as the tube-grown tissues
are thin and have not developed their waxy cuticle
and stomatal flexing. Maintain a high humidity inside
and outside of a perforated dome and an 80-degree
bottom heat. Roots may appear as early as 9 days but
are more common after two weeks.
One good technique is to keep plug trays in
mesh bottom 10 by 20 prop trays and to preload the
plug holes with 1) a drop of diversified root-inhab-
iting organism to penetrate the cube and colonize
roots when they develop, and 2) a drop of root hor-
mone gel. The strategy is to add the hormone second
as a drop where it will coat the inside of the hole and
gravity will keep it in contact with the rough stem
and exposed cambium cut at the bottom. Humidity
will be maintained and do not bottom water the tc
clones until the roots have penetrated the cubes or
you are certain they have all developed.
After roots have developed, you may plant as
regular rooted cuttings, or as we prefer, plant up
into three-inch pots and allow the first few dominant
shoots to develop. I’ve had success taking shoots at
six to eight inches, leaving a single node behind, as
new cuttings by planting directly into fresh rooting
plugs. The rooted clones from tissue culture are dif-
ferent from regular clones primarily because of the
density of shoots at the top of the tiny cutting. I like
to give the secondary branches a chance to add to the
efficient candelabra shape at the same time as get-
ting extra apical clones with all of the advantages of
the tissue culture that it was just derived from. Usu-
ally one to three such clones can be taken from each
rooted tube plants in each 18-site propagation tray.
28
Completing the No-Mother Production Cycle
Eight to eleven weeks after cuttings were placed
into tubes, the pruned and trained veg plants are
ready. Select the top ten or fifteen percent of rooted
clones to be the clone donors of the next generation
and give the rest to the cultivators to flower. Keep
them in the clean environment and take tall dominant
cuttings as they develop and smaller apical cuttings
to introduce into fresh tissue culture tubes. Second
generation cuttings have already been evaluated for
disease and are much more successful than the first
generation. Such small plants as the rooted cuttings,
clone donors and veg plants are best maintained in
rack systems for immediate distribution at the cul-
tivator's convenience. Growth can be slowed or in-
creased with temperature and light levels.
Plants grown in media tubes without contamina-
tion are most likely free of disease organisms and
possess all the advantages of tissue culture. The
plants have directly absorbed the balanced nutrients
and hormones creating sturdy bushy starts and ac-
tivating genes that may have been dormant. Stage 1
Introduction clones may be removed from the tubes,
rinsed and planted in plug trays in a high humidity
environment, creating your new stock. Take clippings
from these veg plants to create new tissue culture
starts. GG
Bill Graham is the owner of Microclone Plant Tissue
Culture and Pure Food Gardening. He can be contacted
at 650.346.8009 or [email protected]. You can
visit his website at Planttc.com.
www.GardenandGreenhouse.net
April 2018