February 2023 - 47

CULTURE REPORT
LINER SIZE
72-cell
32-cell
PLANTING DATES
Weeks 5 to 15
(Once chance of frost has passed)
Weeks 35 to 40
(Once temps start to cool)
CROP TIME
2.5 Qt-1 Gallon
40 to 52 weeks
18 to 26 weeks
It is important to fill pots to the top with soil; this will
help prevent warm roots. Leaving a gap between the top of
the pot and the soil level will cause pots to heat up more
than if the pot is full, potentially burning the hellebore
roots. When planting liners, plant a little deeper than
the surface of the soil. This will help to increase flower
bud development. A top dressing can be used to prevent
weeds as hellebore is a long crop. On our travels, we saw
hazelnut shells used in a few locations; this was a great
top dress using a local resource. In other areas of the
country, rice hulls are often used.
'Winter
Angels
Charmer'
a well-drained soil made with mostly white peat, Canadian
or Baltic, and not more than 20% quality black peat. Black
peat will shrink throughout the growing cycle, causing
poor drainage. Contrary to many crops, hellebores
need a lower soil pH around 5.4 to 5.5; if the pH
goes above 6, it makes uptake of phosphorus
difficult and less flowers will develop.
PLANTING
Starting out on the right foot is
Good quality
soil provides the
aeration needed
for healthy root
development.
important. Whether crops are spring
or fall planted, it is advisable to pot
as early as possible in the season
to get the growth needed to fill the
pot. This is particularly true in the
spring as hellebore grow more quickly
when the temperatures are cooler,
so a delay in planting can stunt the
overall finish size of the crop and
decrease the flower bud count. For
growers not wanting such a long crop
time or for growers wanting to avoid
over-summering a hellebore, fall planting is highly
recommended, as it can cut the crop time in half. The
following chart gives recommended planting dates and
corresponding crop times.
SPACING
Frostkiss and Winter Angel are bred with efficiency in
mind, so most of the crop life they can and should be
kept pot tight, setting in a triangular pattern works best
to eliminate any space where sun can hit the pot. These
varieties do not have a heavy rosette habit, but grow
upright; therefore, they need less space and will not stretch
when grown pot tight. Hellebores enjoy cool roots, so
keeping plants close together causes the foliage to shade
the pot and prevent root burn. Cool roots mean the plants
can grow much bigger and create more flowers by time of
sale. Once plants start to flower in the spring they can be
spaced to give flowers room to develop, just keep them
close enough so pots are still shaded by the foliage.
FERTILIZATION & IRRIGATION
The most important thing with hellebore is to keep
them growing during the year. Never stop fertilizing for
any reason. Hellebore need a steady feed throughout the
growing cycle with an EC of 1.2 to 1.5, measured directly
in the soil. A slow release 8- to 9-month fertilizer is
recommended when spring planted.
In the fall, the shortening of days and cooling of
temperature signal hellebore to initiate flowers so they
need extra nitrogen (N) and iron (Fe) during this time. This
can be supplied using a liquid drench, keeping EC levels at
1.2 to 1.5.
Phosphorus is very important to hellebore. This was one
of the most mentioned topics on our trip. The best ratio
between phosphorus (P) and potassium (K) is 1:3. Aim
at 150 ppm P and 450 ppm K; this is different from many
other plants. Reaching this ratio requires a liquid feeding
on top of the base slow release fertilizer (which is mostly
GREENHOUSE PRODUCT NEWS 47
February 2023

Table of Contents for the Digital Edition of February 2023
