We plant our seedlings when they have hastate leaves and roots
in 3 ounce plastic cups. Once they have several floating leaves,
they can be stalled in this size only for a few weeks before
some that would otherwise survive begin to decline. Other individuals
can be held longer in this size.
It appears, as we write this in mid-winter, that plants moved
up to 8 ounce cups or 4" pots can be stalled indefinitely
at this size. This may not prove true in summer. They stall for
us at the following pad sizes:
'Adventure' & 'Longwood Hybrid' - 4-7"
cruziana - 5-6"
amazonica - 4-5"
Water temperature and nutrients can be reduced to keep the
plants small. Water temperatures in the low 60's at night to
low 70's during the day are adequate for all but amazonica, which
should be kept somewhat higher. Adventure, Longwood and cruziana
will bud and bloom at this size but buds should be pinched off
if the plants are to be grown out. They will decline and die
after blooming at this size.
If moved to 6" pots, plants seem to stall at the following
'Adventure' & 'Longwood Hybrid' - 10-14"
cruziana - 7-9"
amazonica - 10-14"
Reduced fertilizer and water temperatures in the low 60's
at night to low 70's during the day are adequate for all at this
All our propagating tanks are outdoors. At all sizes, we cover
them when the air temperature is expected to be under 50F. This
seems to be the point at which the pads are damaged by the cold
air. We remove the covers as soon as the sun hits the tanks to
prevent excess condensation from spotting the pads. Greenhouse
conditions may provide different results.