I T' T SION VEGETABLE CROPS AUGUST f965
MIX, REPORT 65-2
GROWING RHUBARB IN FLORIDA
JUL 11 1972
James M. Stephens I.F.A.S. Univ. of Florida
Assistant Vegetable Crops Specialist
Florida Agricultural Extension Service
Rhubarb the "pie plant" is a very successfully-grown and popular perennial vege-
table in many parts of the country, but what of its success here in Florida? It has
been said that it does not thrive and is rarely grown where the summer mean temperature
is much above 750 F. and the winter mean is much above 400 F. Thus, Florida gardeners
should not expect much luck with this crop as a perennial, as both our summers and
winters are warmer than this.
We can better understand our disadvantage in growing rhubarb in Florida if we take
a close look at the way cool temperatures affect its growing habits in other states.
The choice parts highly desired for sauces and pies are the succulent leafstalks or
petioles having an attractive red color. Best quality leafstalks result from abundant
vigorous growth starting in the early spring and continuing into the fall. As tempera.
tures become cool in the fall, food produced by the growing plant is diverted in use
from producing leafstalks and other top growth and instead stored in the fleshy crowns.
The crowns then enter a rest period during which growth ceases. In areas of the countr-
where rhubarb does enter a rest period, the tops are killed by cold and the roots remain:
in the soil. Ordinarily, the crowns must be exposed to temperatures near or below
freezing for about six weeks to bring them out of this rest period. If the rest period
is broken, the succulent leafstalks will shoot forth with the first warm days of spring,
if the crowns from which they arise are well-stored with food, the leafstalks will be
large, well-formed, and highly desirable.
Now, in our Florida situation where we have no periods cool enough to send the
crowns into a rest period, let alone severe enough to break the rest period, the plant
continues to grow leaves right on thru the winter to a certain extent. Upon the arri-
val of spring when we would expect an abundant flourish of leafstalks, we find only a
continuance of the old growth.
So the question might be asked, is there adequate growth of leafstalks from a
freshly planted crown in that one year of growth? If so, in Florida we could plant
northern crowns whose rest period had been broken, and harvest in the first two months
of spring enough leafstalks for satisfaction. The answer here is that, in northern
states where rhubarb is grown to a small commercial extent, the leafstalks are not
harvested the first year since they are not produced abundantly enough in the first
year. Even in the second and third years, only the largest and best stalks are har-
vested. But on the other hand, when rhubarb has been tried as an annual in Puerto
Rico at sea level and in the southern United States, some success has been obtained,
even when started from seed rather than crowns. For successful growth as an annual,
rhubarb must be kept growing vigorously, thus requiring very fertile conditions as
COOPERATIVE EXTENSION wORK IN AGRICULTURE AND HOME ECONOMICS
(ACTS OF MAY 8 AND JUNE 30, 1914)
AGRICULTURAL EXTENSION SERVICE, UNIVERSITY OF FLORIDA
FLORIDA STATE UNIVERSITY AND UNITED STATES DEPARTMENT OF AGRICULTURE, COOPERATING
M. 0, WATKINS, DIRECTOR
might occur with an organic soil. But even if crowns from the north, whose rest period
had been broken, would produce abundant stalks in one year's time, there would still be
the problem of obtaining these crowns. Ready availability of crowns contribute much to
the popularity of rhubarb as a garden vegetable in other parts of the country. Once
planted, crowns are always present in the garden, ready to be pulled, divided, and re-
planted. In Florida, this handy source is not at fingertip.
Seeds are easier to obtain than crowns, but plants arising from them show a great
deal of variation in color and form. However, it is possible to sow seed in a seedbed
or seed flat and select the most uniform and desirable plants to set in the garden.
Again, it is questionable whether or not sufficient growth can be obtained in one year
following planting for this method to be practical.
There is another disadvantage to producing rhubarb here in Florida. In addition
to affecting a rest period, cool temperatures also affect the color of the stalks pro-
duced. Stalks grown at temperatures as low as 500 F. develop more intense pink color
than those grown at 600 F. or 700 F. Under our warm conditions in Florida, it has been:
noted that stalks do not produce a good, deep pink color, especially when grown in the
spring. Color of stalks should be better when grown through the winter in Florida.
Varieties--Victoria is an old variety that produces large but poorly colored stems
Burgess' Colossal is also large but produces pale green stalks. Canada Red, MacDonald,
and Ruby are popular red-stalked varieties. It is not known which varieties are best
adapted to Florida.
Soils--Due to the need for fast, vigorous growth, a most fertile soil is desirable
If possible, the organic content of the soil should be high, as would be the case with a
muck or peat. A sandy home garden plot should be spaded deeply and abundantly supplied
with well rotted manure, leaf mold, or peat.
Fertilization--Rhubarb requires large amounts of moisture and mineral nutrients
during the growing season. While the fertilizer requirements on Florida soils have
not been worked out, it is likely that as much as 1500 to 2000 pounds of a 6-8-8 ferti-
lizer (or 3 to 5 pounds per 100 sq. ft.) could be utilized at planting time, depending
on an abundant, uniform, moisture supply. Again, rhubarb responds well to liberal
applications of manure, which, when applied prior to planting, should be accompanied
by 2 pounds of superphosphate for every 25 pounds of manure.
Planting--It is suggested that rhubarb be grown in Florida as an annual, either
from seed or from crowns. If from crowns there is a possibility of three methods: 1)
Crowns may be purchased from northern seed companies as early in the spring as is pos-
sible to obtain crowns whose rest periods have been broken. These crowns may either
be planted whole or cut into pieces containing one or more buds. Large pieces are more
desirable than smaller ones. Set the pieces of the crown and root so that the buds are
2 to 3 inches below the soil surface. Space plants 12 to 30 inches apart in rows spaced
2 to 3 feet apart.
2) Crowns may be obtained from the north in late summer, placed in cold storage
(freeze them solid for 6 weeks) to fulfill rest requirements, and planted in the fall
or early winter. With this method employed in north and central Florida, there would
be danger from killing cold.
3) Winter forcing is a third method using crowns. It is a common commercial
practice in the north, and may be of some value to home gardeners in Florida. Roots
which are 2 to 3 years old and which have had a rest period are placed under more or
less artificial conditions where they will sprout and produce stalks. Obtaining such
roots is probably the limiting factor in the practice of forcing here in Florida.
Such roots are placed one per square foot in a forcing structure (hotbed, cold frame,
etc.) and covered with a soil sawdust mixture. They should be watered thoroughly and
kept at a temperature of 50 to 600 F. Light is undesirable and direct rays should be
eliminated. Stalks of good color and a length of 18 inches should develop in 25 to 30
If seed are planted, they should be sown either in a seedbed or directly in the
garden row. If in a seedbed, desirable plants should be selected when 3 to 4 inches
high and set in the garden row at the same spacing as for crowns. If directly seeded,
plants should be thinned to stand about 12 inches apart in the row.
In south Florida, where temperatures seldom drop below 320 F. (rhubarb will
withstand temperatures down to this), seed might be planted in September in a seed
flat, transplanted in the garden in October, and harvest begun by about February. In
central and north Florida, a similar procedure might be observed, but greater risk of
having plants killed by cold would be run. Lower temperatures during this winter perio
should improve color of the stalks. Again, it is likely that stalks produced in such
a short time from seed may be rather small and somewhat poor in quality.
Harvesting--Stalks from rhubarb grown as an annual should be pulled as soon as
they reach a desirable size. Stalks should be pulled or twisted rather than cut. Afte'
pulling, the stalks should be trimmed off near the base and protected to prevent wilt-
ing. For local markets, the stalks are sold loose, or washed and tied in bundles of
one pound or more. The leaves of rhubarb should never be eaten, as they contain suf-
ficient amounts of oxalic acid and oxalates to bring about gastronomic disturbances.
"Rhubarb Production Outdoors and In," USDA Leaflet No. 354. 1963.
"Rhubarb Forcing," USDA Leaflet 137. January, 1939.
"Suggestions for Rhubarb Culture," Michigan Agricultural Extension Service Folder F-143
"Vegetable Gardening in the Tropics," USDA Puerto Rico Circular 32. October, 1950.
"Vegetable Crops," H. C. Thompson. 1949.
"Botany," C. L. Wilson. 1952.
"Burgess Seed Catalog," Burgess Seed and Plant Company, Galesburg, Michigan. 1965.
"Growing and Marketing Florida Truck Crops," Florida Department of Agriculture. 1950.