Some tests in the culture of peppers

JBRARY OF

UNIVERSITY OF ILLINOIS
AT URBANA-CHAMPAIGN

AGRICULTURE

CIRCULATING

CHECK FOR UNBOUND
CIRCULATING COPY

UNIVERSITY OF ILLINOIS

Agricultural Experiment Station

BULLETIN NO. 274

SOME TESTS IN THE CULTURE
OF PEPPERS

BY J. W. LLOYD

URBANA, ILLINOIS, APRIL, 1926

SUMMARY

Green peppers of the large type have become very popular for
salads and for stuffing. Their culture is profitable where good yields
can be secured. Under Illinois conditions, the use of large, well-grown,
potted plants is favorable to early bearing and large total production.
The tests reported in this bulletin were made to determine other factors
affecting yields.

Altho the pepper plant will withstand considerable dry weather,
the yields, as an average for five years, were increased about 15 per-
cent by supplementing the natural rainfall with overhead irrigation.

Neither the use of nitrogen in the form of nitrate of soda, nor of
phosphorus in the form of bone meal, resulted in any consistent
increases in the yields of peppers.

A comparison of six varieties indicated that Neapolitan Salad was
the earliest, but that Sweet Mountain was the heaviest yielder.
Chinese Giant was the poorest yielder.

FIG. 1. — SWEET MOUNTAIN PEPPER
This variety yielded an average of 3 pounds of peppers to a plant.

SOME TESTS IN THE CULTURE
OF PEPPERS

By J. W. LLOYD, Chief in Olericulture

Green peppers of the large, mild or sweet type, used in salads
and for stuffing, have increased greatly in popularity within the last
few years. Their use in salads especially has recently become quite
important, and they are shipped from the South to northern markets
at seasons of the year when the northern home-grown product is
not available. Illinois gardeners have had trouble in taking advan-
tage of this increased demand, because of failure to get satisfactory
yields. It is a common occurrence in the North for peppers to produce
very few fruits until late in the fall, and then to be caught by frost
with the main crop still on the plants too immature to be of value.

Some tests were therefore planned by this Station with a view
to developing a method by which growers in Illinois would be enabled
to produce larger yields before the close of the growing season. The
tests were made on rich garden soil of the brown silt loam type, at
Urbana, starting in 1919 and continuing thru the season of 1923. They
included the growing of peppers with and without irrigation; with and
without applications of nitrate of soda; with and without bone meal;
as well as a comparison of different varieties.

Previous experience had shown that large, well-grown, potted
plants have a much better chance of producing satisfactory yields
before the close of the season than have plants that are small, young,
or poorly developed at the time they are set in the field. A pepper
plant normally continues to bear until killed by frost, and an early
start gives it a longer bearing season. All the pepper plants used in
the present tests were grown, therefore, from early-planted seed, and
handled in a manner to put them in ideal condition when the time for
setting in the field arrived.

METHOD OF CONDUCTING THE TESTS

The pepper seed was sown in flats in a warm greenhouse in March.
As soon as the plants were large enough to handle to advantage, they
were shifted to 2% -inch pots, and were later transferred to 4-inch
pots. At the time they were set in the field the plants were large and
well developed, usually showing buds and sometimes blossoms. These
potted plants suffered very little check in growth when placed in the
open ground.

Four rows of pepper plants were set in the field, two where they
could be irrigated by the overhead Skinner system. The rows were

331

332

BULLETIN No. 274

[April,

3y2 feet apart and the plants were placed 2 feet apart in the row. The
various lots were designated as follows:

Lot 1. Not irrigated nor fertilized (check)

Lot 2. Not irrigated, but fertilized with bone meal

Lot3. Irrigated but not fertilized

Lot 4. Irrigated and fertilized with nitrate of soda

The object of making these combinations of treatments was to
determine whether fruitfulness in the pepper could be stimulated by

the use of phosphorus, which is
supposed to increase the yields of
fruit-bearing plants; or whether
fruitfulness in the case of this
plant might be associated with a
strong vegetative growth. Irriga-
tion was resorted to as one means
of promoting vegetative growth.
With a view to stimulating such
growth still further, if possible,
nitrate of soda was used in addi-
tion to irrigation on one of the lots.
Six varieties — Neapolitan Salad,
Sweet Mountain, Crimson Giant,
Magnum Dulce, Chinese Giant,
and Ruby King — were included in
the tests each year except in 1920,
when Ruby King was omitted.
Each variety was grown under
each of the treatments mentioned.

In 1919 only 9 plants of each variety were grown under each
treatment; in 1920 and 1921, 15 plants of each variety were used, and
in 1922 and 1923, 20 plants of each variety.

The bone meal was applied at the rate of 2 ounces per plant, and
was mixed thoroly with the soil at the time the plants were set. The
nitrate of soda was used at the rate of 1 ounce per plant for the season,
but was applied % ounce at a time. The first application was usually
made about four weeks after the plants were set in the field, and the
second applicaton about three weeks later.

The peppers were picked when in the right condition for market,
that is, when they appeared to have reached their maximum size but
were still green. A number of pickings were required to harvest the
crop. When the weather was warm and the peppers were developing
rapidly, it was found necessary to pick over the plantation once a
week to get the crop in optimum condition. When the weather was
cooler, less frequent picking was necessary. The number of pickings
each year was as follows: 1919, twelve; 1920, fifteen; 1921, twelve;
1922, nine; 1923, six.

FIG. 2. — TYPE OF PLANT USED IN THE
TESTS. GROWN IN 4-lNCH POT

1926}

SOME TESTS IN THE CULTURE OF PEPPERS

333

In 1923 the weather was very cool and the crop was cut off by
frost on September 12. In the other years, picking was continued into
October. Dates of planting, transplanting, and harvesting are given
in Table 1.

TABLE 1. — DATES ON WHICH PEPPERS WERE PLANTED AND HARVESTED

1919

1920

1921

1922

1923

Seeded

Mar. 19

Mar. .5

Mar. 19

Mar. 7

Mar. 9

Shifted to2V£-inch pots

Apr. 11

Mar. 29

Apr. 12

Mar. 23

Apr. 2

Shifted to 4-inch pots ....

May 10

Apr. 25

May 5

Apr. 17

Apr. 23

Set in field

June 13

May 28

June 1

May 24

June 2

First picking

July?

June 25

June 24

June 27

July 2

Last picking

Oct. 8

Oct. 9

Oct. 8

Oct. 9

Sept. 12

YIELDS INCREASED ABOUT 15 PERCENT
BY IRRIGATION

Whenever the rainfall was insufficient to keep the peppers well
supplied with moisture, the two rows planted near the irrigation pipe
were thoroly watered. The results of irrigation are indicated in
Table 2.

In 1919 all varieties produced larger yields without irrigation, and
in 1920 the average yield was slightly greater from the non-irrigated
plants, owing to the relatively light yield of one variety under irriga-
tion. In the other three years, however, the yields of all varieties were
greater from the irrigated plants ; and the five-year average for all va-
rieties shows an increase in yield of 15 percent apparently due to
irrigation.

NITRATE OF SODA FAILS TO INCREASE YIELD

For all varieties during all five years, in 20 trials out of 29, the
nitrated plants yielded less than the plants without nitrate (Table 3).
Four of the varieties, as an average of the five years, yielded less
with the nitrate treatment than without it; the other two varieties
yielded slightly more with nitrate. The five-year average yield for all
varieties combined was slightly in favor of the plants that were
grown without nitrate.

It is quite evident that the yielding propensities of the plants
were not improved by the applications of nitrate of soda.

BONE MEAL GIVES NO CONSISTENT GAINS

Under the conditions of this experiment, no consistent advantage
was derived from the use of bone meal (Table 4). In 1921 the yields

334

BULLETIN No. 274

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336 BULLETIN No. 274

were distinctly better from the plants treated with bone; but in all
other years the average yields, including all varieties, were lower from
the bone-treated plants than from the untreated plants. Furthermore,
the five-year average yield for all varieties combined was slightly
greater from the untreated plants.

COMPARISON OF VARIETIES FOR EARLY
AND LATE USE

Marked differences were discovered in the yields of the six varie-
ties of peppers included in these tests.

For the sake of making a fair comparison of the varieties, early
yields and total yields of all six varieties as grown without irrigation
or special fertilizer treatment, are tabulated in Table 5. All peppers
harvested before August 15 were considered "early." Ordinarily only
a relatively small proportion of the crop was picked before that date.
Some varieties, however, produced a much larger yield of early pep-
pers than did other varieties. Neapolitan Salad was the outstanding
variety so far as earliness was concerned, while Chinese Giant and
Magnum Dulce were notably deficient.

So far as total yields were concerned, Sweet Mountain outyielded
all the other varieties, its average yield for the five-year period as
grown under all four treatments being more than double that of Chi-
nese Giant, the lowest yielding variety. Furthermore, Sweet Moun-
tain was second only to Neapolitan Salad in average yield of early
peppers. Since Neapolitan Salad is of rather small size and suitable
only for salad, rather than being adapted also to stuffing, Sweet
Mountain is the better variety for general use, both early and late,
when grown on brown silt loam under the conditions obtaining in
the corn belt. It is of course possible that Chinese Giant might
do relatively better on some other soils or under other conditions.
The important point brought out by these tests is that there are great
differences in yields of different varieties, and each gardener should
grow a variety that will give large yields under his soil and climatic
conditions.

CONCLUSIONS

1. It is feasible to grow peppers on brown silt loam as ordinarily
fertilized for market gardening purposes, without special treatment
with commercial forms of nitrogen or phosphorus.

2. Peppers will withstand considerable dry weather, tho the yields
may be somewhat increased by an abundant supply of moisture.

3. Treatment with nitrate of soda in addition to irrigation seems
to be detrimental to the yield.

4. Varieties of peppers differ widely in productiveness. Under the
conditions of these tests, Sweet Mountain proved to be a much heavier
yielder than any of the other five varieties tested.

UNIVERSITY OF ILLINOIS-URBANA