THE FIR BARK STORY 
By LEO HOLGUIN 
Orchids, as most of us know, have been 
grown in many different media and composts 
—Osmunda, Leaf Mold and Redwood Bark, 
Tree Fern Bark, Sand, Gravel, and almost 
everything else under the sun, excepting, 
maybe, the kitchen sink. As one grower re- 
marked: “You can grow them on concrete 
once you learn how.” 
Most materials with the exception of Os- 
munda tend to break down rapidly which 
makes them impractical for the commercial 
grower to use. However, now we have the 
new wonder media, Fir Bark, which should 
last as long as Osmunda it is reported. A 
year or two ago a few growers started to ex- 
periment with this material and report excel- 
lent results. 
At Armacost & Royston we started to ex- 
periment with Fir Bark in August of 1955. 
We have one house with mature Cattleyas in 
this material and two benches of Cattleyas 
potted in steam sterilized Fir Bark. In the 
benches the material is three inches deep. 
Up to February, 1956, the plants have 
shown an increase in root growth. The top 
growth seems to be about the same as when 
Osmunda is used. We will not know about 
the quality of the flowers until the Summer or 
Fall of 1956 when the plants come into 
bloom. 
At this time, February 1956, we can say 
that results thus far are satisfactory. We can- 
not say, frankly, that Fir Bark will take the 
place of Osmunda. At least two years of ex- 
perimentation will be required. We want to 
learn definitely just how long Fir Bark will 
last before breaking down. 
In addition to the above plantings we have 
a bench of Seedlings in Fir Bark and they are 
doing very well. We are also using the mate- 
rial in our Cymbidium and Cypripedium com- 
posts in place of pine shavings or redwood 
bark, as formerly. We use the Fir Bark as it 
comes from the mill for all mature plants. 
For seedlings we screen out the coarse and 
very fine grades. 
We use 10 pounds of Dolomite lime to 
one cubic yard of Fir Bark which brings the 
PH up to about 5.9. We feed every other 
watering with Ammonium Nitrate (33.5% 
Nitrogen), one teaspoonful to a gallon of 
water, or 8 to 50 gallons. 
An analysis is taken about every other 
month and during the past six months all we 
have had to add has been Nitrogen. The PH 
remains around 5.9. Fir Bark has a high Phos- 
phate and Potassium content, but is low in 
Nitrogen and Calcium. 
Fir Bark costs less than most other mate- 
rials and is less expensive to use because 
potting and watering are easier and faster. 
The big question is — How long will Fir 
Bark last before breaking down? Will it re- 
place Osmunda — will the plants continue to 
thrive in years to come as they have thus far? 
Only time will tell. 
= Gy hae 
