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, 3y 2 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 [April, g "a K (- 03 4> h- < 9) i( CO GO fC O i-l * C4 8 < CD * OS (N O^C CO-* (M CCIMCO CO CO S9 GOOD O CD OS 00 o OS 000 tH(M O H (N CO CO t> * Tt< CO N TJ 5 03 if i 1 ^H IM (N GO 00 CO CC-* (NIN'-KN 05 (N B ,_, CO TH CO ^ 0? I-H 00 "* i-i CO i-H 00 (M (N 1-1 i-H .-1 U9 I-H (N (M OS 1C * 1C CO CO T3 1 03 OS i I O CO CO GO CO <-l co OS i OS OO (N T-I 1> * Tt< t^ 10 * io co K. IQ 8 * GOOS GOlO t* OS I-H CD 1C lOCO COIM COCO 5> | I 'S.S ' : 3|i-i| g3a|s |5 1 l in|i| !^cuSc;pH Average H P o i o o 1 OCOiOCOI>CO CO < lO (N CO * 1^ * COOCOCO OS 1 1 OSOO(N ^Ht^-* * l> iO * O CO t^ 1C Tfl OOOS 00 O l^ C1 OS I-H T-H COlO 1C CO COIMCOCOlM S 05 o 1 ^ * i-l (N CO OS kO CO O CO CO PI OS COOO3O iM 1-H 03 (M CO r-\ I> i-H OS CO 00 S ^3 -i- S T 1 CO-* O OOCO CO CO COIN CO C^l id o -* E 'B i-H I>COCOOSC(N CO ts Ol be L_ OS IO(N C^Jt^^CO *00"2"5OCO OS o 8 iO-CO 00 OS i-H rf f- OS OO OS COCOCOINiM CO co OS rt< i-H CO O OS O CO OS rH f^COOSCXN rH CO IO CO CO CO 1C *f 4 i ! ^ 5 Neapolitan Salad Sweet Mountain. . Crimson Giant. . . Magnum Dulce. . . Chinese Giant Ruby King Average 1926] SOME TESTS IN THE CULTURE OF PEPPERS 335 V If CD CO !O CO I-H Tf (N I 4 CO * OS "3 Tt< co os 1C C3 - - 1 t-t-t-t-0^ l> EH Jt ft - Ct> ~ ^ COIN O5O t^CO CO-*(NCOrHCO 1-H CO u 5 s CO CO 00 00 3 o "3 Oi OS T 1 COt^OOOt-N i I i-( i I C*J 1-H i 1 z s o> C C CO C ^ CO "5 OS * 3 H I fe u s > Neapolitan Salad Sweet Mountain. Crimson Giant. . . Magnum Dulce.. Chinese Giant. . . Ruby King Average as E 2 O r e* H K Q N 2 3 ^H w !l M a, *< S S5 6g fi h O a g H 2 > a CO 00 CO CO I-H TJ< IN 0> I H CO-* IN CO (N CO CO CO i >, t^ 1C IN I-H CO CO 1-H 1 CO-* COi-H IN CO Is OOOOOCOO500 CO CO 1 1C 00 -H (N O 1-H i-H i-H T 1 1-H OS i-H >, (N^OSOt- c 03 W T* COCOCOOfN CO a CO CO t^ Tf ^i CO , OS t^ ' "^ C^J * < OS & *CO 1-H * 1C OSOOO OCO OS CO COO O CO -H *a -HCOOOCOOO t-- O IN C i-l IN * CO COIN 1-H co T ( b IN <* i-H O "* (N ^ OCOCO I-H i 1 "* *a t^ COI> COIN O CO Oi o H CO O C CO C "* CD s OS i-H O r-l i-H OS 00 00 00 03 W i-H 1C CO ^ i-H <* ' 1 a U Neapolitan Salad. Sweet Mountain . Crimson Giant . . Magnum Dulce.. Chinese Giant. . . Ruby King Average 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