Minnesota Flower Growers Bulletin - January, 1991
Volume 40, Number 1
Light: Although each cultivar has its own optimum light level, most cultivars perform best at approximately 5,000 footcandles
When planting tubers out-of-doors, tubers should be planted when the soil
temperature is 65OF (18oC) or above.
medium begins to dry.
Do not overwater as
'Holland Bulb Forcer's that caladiums should 4,000 footcandles.
Guide' recommends be grown at 3,000-
root and tuber rot will occur. plants should not be allowed irreversible damage may occur.
However, to wilt as Tubers may
Insufficient light results in smaller leaves, reduced plant height, and reduced
results in increased
chlorophyll (green pigment) Plants may also be stunted and leaves.
production. have smaller
Temperature: Tubers should be stored after
harvest (cured) to promote rapid after planting (see propagation).
involves exposing tubers to 9OoF for3 days
then storing tubers at 70-75oF for at least 6 weeks for early forced caladiums or storing
tubers at 70-750F constant temperatures for caladiums forced later in the season.
Most pot plant producers receive tubers that already have been cured by the tuber
If tubers are
not to stored.
be planted Generally,
temperatures of 70 - 80oF (21 - 27oC) are recommended for storage. Relative humidity should be maintained at approximately 75%. Good air circulation should be maintained to prevent build up of undesirable gases and to prevent fugal growth on tubers. A fungicide
dust may also be applied to prevent fungal growth on the tubers. Tubers should never be
below 70oF (21oC).
Temperatures can be raised to as high as 9OoF (32oC) to increase the rate of leaf emergence.
However, forcing at 9OoF temperatures reduces root
(32oC) or higher
When caladium are with plants which prefer a
in a cooler
temperature, cover to increase the pot
pots with a
humidity under the plastic. After leaves emerged, temperature can be lowered to
fertilizers are acceptable.
Conover and Poole
recommended 6 kg Osmocote (14-14-
per cubic meter of medium (6 ozkubic
ft) or 1 tsp per inch (15 cm) pot diameter. A constant feed of 100 - 200 ppm nitrogen and potassium weekly has also been used to successfully grow caladium. Superphosphate may be added prior to potting. The pH should be maintained at 5.5 - 6.5. Dolomitic lime may be added to the mix prior to potting to
raise the pH if necessary.
Excess nitrogen may cause undesirable green leaves (due to over production of chlorophyll).
Gases: - A high relative humidity (75%)
is required during storage to reduce tuber
No information is available
the affect of C02 on caladium growth.
PrODCiaatiOn - Caladium propagation is
accomplished by tuber multiplication, tissue
culture or by seed. common means of
Tubers are the most caladium propagation.
Tuber propagation is usually conducted in the spring. Pieces of tuber (1 cubic inch) with at least 1 bud are planted in the field in spring. Before planting tuber pieces are soaked in hot
(122oF) for 30 minutes. and tubers are harvested in
The tubers are placed in drying and then placed in
open containers for a forced air building
for curing (70 - 80oF, 75% RH). results in more rapid sprouting.
curing, tubers are dipped in or dusted with a fungicide.
Caladium tubers are graded by the circumference of the tuber. Tuber grades and the respective sizes are shown in Table 2.
(21oC) without plant growth.