Light & Dark Cycle
Alternatively, you can alter the amount of daylight it receives
and trick it into bloom. Christmas cacti and poinsettias require
14 hours of darkness every night to initiate flowering. Simply
cover your Christmas cactus with a box or put it in a closet or
an unused room from 6 p.m. until 8 a.m. Once the flower buds
form, you can keep it in its usual place.
If you are moving your plant from place to place, be careful to
maintain the same orientation toward the sun. Otherwise, the
flower buds will try to point themselves toward the sun. If this
happens repeatedly, they will weaken to the point of falling off
the plant before they open.
Remember that Christmas cacti are jungle cacti rather than
desert cacti. Water them as frequently as your other
received a beautiful Christmas cactus that was just loaded with
flowers and unopened buds. I'm concerned because quite a
few of those flower buds are falling off before they open. Can
you tell me why this is happening to my Christmas cactus and how
I can stop it? Would it help to fertilize it, and if so, what
fertilizer should I use?
Flower bud drop is one of the most common problems with
Christmas cacti. It is caused by a number of factors, ranging
from a sudden change in light or temperature to excessive or
insufficient water. Since you received your plant recently, the
problem could be as simple as moving it from the ideal
greenhouse conditions where it was grown to your home where the
air is probably drier and perhaps the light is not as bright.
Christmas cacti perform best in bright, indirect light.
Their leaves can burn if they are exposed to full afternoon sun,
even indoors. Also, their flowers will fade quickly and their
buds will drop from excessive heat in such a situation. It is
also important to site them away from heat vents because dry air
blowing on them can also cause bud drop. Likewise, avoid placing
them where they will be exposed to cold drafts from outside
Not a desert
Despite the word “cactus” in their name, Christmas cacti are not
desert cacti and will not tolerate extremely dry soil. They
prefer evenly moist, but never saturated soil. Ideally, you
should move your plant to a sink or bathtub to water it. Water
until it drains from the holes in the bottom of the pot. (If the
pot it is growing in does not have drainage holes in the bottom,
repot it into one that does). Allow it to drain thoroughly, and
then return it to its usual spot. If it is too large to move
easily, be sure to drain excess water from the saucer so that
the plant is never sitting in water for any length of time.
Allow the soil to dry slightly between waterings. You can stick
a finger into the top inch or two of soil to check for
sufficient moisture. If the soil feels dry, go ahead and water;
if it is still moist, wait until it feels dry before you water
again. Keeping a Christmas cactus too wet will result in root
rot, which can also cause bud drop, and will eventually kill
Avoid fertilizing your Christmas cactus when it is blooming.
We typically recommend fertilizing houseplants from April
through September, when they are actively growing and can make
good use of the nutrients. Houseplants respond to the lower
light levels in our homes during the winter and cease active
growth. When you do fertilize, use a balanced, water-soluble
fertilizer such as Miracle-Gro, Peters 20-20-20, liquid sea kelp
or fish emulsion. Always read and follow label directions. When
it comes to fertilizer, more is never better.