5°8 
THE NATIONAL NURSERYMAN 
THE PREPARATION AND USE OF CONCENTRATED 
LIME-SULPHUR 
By J. P. Stewart 
Experimental Horticulture, State College, Pa. 
The spraying part of the horticultural world is just now 
in a state of transition. This transition involves the break¬ 
ing away from Bordeaux mixture and the whole list of 
copper sprays which have served for a quarter of a century 
as fungicides and the taking up of what may become an 
equal list of sulphur sprays. It also involves the abandon¬ 
ment of old formulas and processes for making the latter 
sprays and the substitution of more definite, economical and 
less disagreeable methods. Just how complete the transi¬ 
tion will be can hardly be predicted now. But this much is 
certain that, whereas two years ago we might easily have 
told how best to spray a tree today we must wait for further 
results before this question can be finally answered. 
Among these coming sprays, the clear concentrated lime- 
sulphur solution will undoubtedly occupy a leading place. 
In the commercial form this solution already has a satisfac¬ 
tory insecticidal record of some seven or eight years. In 
the new home-preparation, it has an excellent record both as 
an insecticide and fungicide, being first used by Cordley of 
the Oregon Station in 1907 1 . Realizing the importance of 
this work, in the latter part of 1908, the writer undertook to 
determine the essential features of the preparation of 
storable lime-sulphur solutions and if possible render their 
use available to orchardists. 
In brief, the results of this study are as follows: In the 
making of a storable lime-sulphur at home, we must first get 
the formula right. This is accomplished by using one pound 
of good lime 2 , two pounds of sulphur, and one gallon or a 
little more of water, boiling it all down so as to have about 
one gallon of total product at the close. This 1—2—1 formula 
can be made up in any quantity, merely noting that the 
pounds of lime and the gallons of final product are the same 
in number, while the pounds of sulphur are just twice as 
many. 
The kind of sulphur may be either flour, flowers, or 
“powdered commercial” at least 99jj%pure. The last 
named is probably most desirable, with the flour next, on 
account of cheapness and the somewhat lessened tendency 
to form pellets in the process of mixing. 
The utensils needed are a cooker, measuring stick, strainer 
and hydrometer. Their total cost need not exceed $15. 
They are described in detail in our Bulletin 92 1 , so that it 
will suffice here to say that the cooker may be of either iron 
or wood and use either bottom heat or steam. If steam is 
used it is preferable for accurate work that it be in closed 
coils, rather than live steam, at least in the latter stages of 
the process. This is merely because it is desirable that the 
final volume be under control and be decreasing rather than 
increasing. Steam jacketed kettles with mechanical agita- 
: An account of his work appeared in the Rural Neiv Yorker of March 1908 but 
without any statement of method of preparation. This appeared in “Better Fruit” 
in April 1909. 
2 0ne containing 90 to 95 per cent calcium oxid and as little magnesium as 
possible. 
tors are available and they work very nicely, indeed. But 
where storage is not considered and lower densities are per¬ 
missible, there is no objection to making the material with 
the use of live steam throughout. 
Details of Preparation 
In making fifty gallons of concentrate the procedure is as 
follows: 
[Penn. Expt. Sta. Bui. 92 , July, 1909 . This bulletin contains 
full practical directions for making, preserving and diluting lime- 
sulphur solutions, together with a table of uses. It may be obtained 
for the asking by writing the Experiment Station, State College, Pa. 
Materials: 
50 lb. best stone lime (not over 10% impurities). 
100 lb. sulphur (kind stated above). 
50-55 gallons of total product, at finish. 
Put 10 gallons of water in kettle and start fire. Place lime in 
kettle. After slaking is well started, add the dry sulphur and mix 
thoroughly, adding enough water to maintain a thin paste, which 
requires about five gallons. After the slaking and mixing are com¬ 
pleted, add water to the height of 50 gallons on the measuring stick 
and bring to a boil and stir until the sulphury scum practically 
disappears. Then add water (preferably, but not necessarily, hot) 
to the 60 -gallon 1 height and boil again to 50 gallons, if storage space 
is limited. If it is not limited, a little more water may be added the 
third time and boiling stopped at about 55 gallons. The material 
should be kept well stirred, especially during the early stages of the 
process, and any lumps of sulphur or lime should be thoroughly 
broken up. 
The time of boiling should be until the sulphur granules are 
evidently dissolved. This fact is best determined by dipping and 
slowly pouring some of the material, under close observation. In 
many cases we have obtained as complete dissolving of the sulphur 
in less than forty minutes of actual boiling as was obtained by anv 
time up to two and a half hours. In general a period of forty to sixty 
minutes of actual boiling should be safe and sufficient to put the 
sulphur into solution. But the amount of sulfites and sulfates and 
therefore the sediment, are undoubtedly increased by unduly pro¬ 
longed boiling. Hence, the amount of water added in the third 
addition should be so regulated as to permit the necessary boiling 
and just reach the desired volume at the close. This gives the least 
sediment and the regulation can be easily accomplished after a few 
trials. 
The finished product may be immediately poured, or strained into 
a barrel, or settling tank. The straining is merely a safeguard to 
prevent possible clogging due to imperfect materials, or failure to 
break lumps in the sulphur. When properly made, the amount of 
sediment left in the strainer is insignificant. To avoid any con¬ 
siderable loss of materials, it may be washed with part of the water 
used in making the next lot, simply pouring the water through the 
strainer into the kettle, and any lumps of sulphur discovered may be 
broken up and used again. 
The sediment is of apparently no value as a spray material 
against insects, 2 hence its volume and removal, especially in the 
commercial preparations, become matters of importance. It is 
composed largely of sulfites and sulfates of calcium, together with 
ylf cooker is large enough, the whole amount of water may be added immediately 
after mixing in the sulphur, thus avoiding the check in boiling though greater care 
is required to prevent boiling over. A 75 gal. cooker is large enough for this. 
2 As indicated by the work of Parrott at the Geneva New York Station. 
