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Growing Chiles in New MexicoGuide H-230Paul W. Bosland and Stephanie Walker1Cooperative Extension Service College of Agricultural, Consumer and Environmental SciencesCHILES IN NEW MEXICOChiles (Capsicum annuum) havebeen grown in New Mexico forat least four centuries. Chile isan important cash crop for farmers, with approximately 8,000 to10,000 acres harvested annuallyin New Mexico. Most chiles aregrown under contract and soldto processors. Several differentand distinct processors operatein New Mexico, depending onthe type of chile handled. For example, New Mexican-type greenchile is peeled, then canned orfrozen, and is packed whole ordiced. Red chile is usually harFigure 1. Test plots of new chile varieties at the Fabian Garcia Research Center invested in the red, ripe, partiallyLas Cruces, NM. (NMSU photo by Robert Yee)dried stage, and is further dehydrated at the processor beforefinally being packaged as dried whole pods, flakes,CULTIVARSor powder. Paprika is no-heat (nonpungent) orMany types of chile are grown in New Mexico, inlow-heat red chile that is usually highly pigmented.cluding New Mexican type, cayenne, paprika, andMore than 50% of the paprika crop is processed tojalapeños. New Mexican-type cultivars includeproduce a red oleoresin colorant through extraction‘New Mexico 6-4’, ‘NuMex Big Jim’, ‘Sandia’,of the colored pigments. Cayenne peppers are a‘NuMex Garnet’, ‘NuMex Joe E. Parker’, ‘Arizohighly pungent type that are picked in the red sucna-1904’, and ‘Arizona-20’ (Figure 1). Processorsculent stage and undergo a salt fermentation at prousually dictate specific cultivars of chile that mustcessing plants as the primary step in conversion tobe planted for their contracts. Many of these culhot sauce. Jalapeños are usually pickled and packedtivars, especially in the red chile and paprika induswhole or sliced, but a small percentage is dehytries, are proprietary lines developed specifically fordrated. Chiles for local sale are a relatively smallor by the processor. If you are able to choose whichpart of total commercial chile acreage, but chile iscultivar to plant, you should consider its yield, disa good cash crop for small-scale growers. Dried redease resistance, adaptability, and market acceptance.chiles can be strung on ristras for ornamental andculinary use.Respectively, Regents Professor, Department of Plant and Environmental Sciences; and Extension Vegetable Specialist, Department of Extension Plant Sciences,New Mexico State University.1To find more resources for your business, home, or family, visit the College of Agricultural, Consumer and EnvironmentalSciences on the World Wide Web at aces.nmsu.edu

A good source of information on these and otherNew Mexico State University (NMSU) cultivars isResearch Report 763, The Chile Cultivars of NewMexico State University Released from 1913 to re/RR-763.pdf ).PREPARING THE LANDA good crop rotation plan is critical for a productive chile crop and for management of pests anddiseases. A three- to five-year rotation schedule, inwhich chile is planted once in a field and a grain(monocot) crop is planted at least once, has provento be beneficial for growers in New Mexico.A deep, well-drained, medium-textured sandyloam (or loam soil) is best for producing chiles.Good yields often result from planting chiles in aplace that contained a flood-irrigated crop the previous year. Laser level the field at a grade of 0.01 to0.03% in one or both directions. This drains thefield of extra water, reducing the risk of root diseases.Preparing soil involves plowing, deep chiseling,discing, smoothing, and listing. Form listed bedsby scalping the top of the ridge with a drag harrow.Irrigate the field 2 to 4 weeks before planting, andplant chile seed before the soil dries.FERTILIZINGIn New Mexico, nutrients normally used on chilesare nitrogen and phosphorus. A soil test can determines the soil’s nitrogen, phosphorus, and micronutrient needs. See NMSU Cooperative ExtensionGuide A-146, Appropriate Analyses for New MexicoSoil (http://aces.nmsu.edu/pubs/ a/A146.pdf ), forinstructions on how to collect soil samples. Submityour samples to an appropriate laboratory for determination of nutrient needs, pH, salt E.C., andsodium level.Broadcast the first nitrogen application and allthe phosphorus before discing or listing. Band nutrients either when seed is planted or after seedlingshave emerged. Phosphorus helps young seedlingsgrow, especially when the soil warms in spring.Phosphorus is not needed if soil phosphorus levelsare between medium and medium-low, based onthe NMSU analysis system (Guide A-122, SoilTest Interpretations, http://aces.nmsu.edu/pubs/ a/A122.pdf ). Add 50 to 100 lb of P2O5 per acre be-fore discing if levels are lower. Alternatively, bandphosphorus (30 lb of P2O5 per acre) 3 to 4 inchesbelow the seed.Preplant nitrogen also generates vigorous seedling growth, which ensures a well-branched plantby the first fruit set. Preplant nitrogen is not neededif a soil test shows the soil has 20 ppm nitrate ormore. If nitrogen is needed, broadcast 20 to 30 lb ofactual nitrogen per acre before discing. Otherwise,band nitrogen (2 to 5 lb per acre) 3 to 4 inches below the seed.Post-emergence nitrogen fertilization dependspartly on whether the crop will be picked at themature green stage or at the mature red stage. Normally, a mature green chile crop requires more nitrogen, particularly when second-harvest fruits develop. Apply a sidedress of 20 to 30 lb of nitrogenper acre in mid-June when primary and secondaryfloral buds are evident and plants are 8 to 10 inchestall, and again in early July when many first-setfruits develop. Apply fertilizer in a continuous band4 inches to the side of the bed and 2 to 3 inchesbelow the surface. Alternatively, liquid fertilizer solutions can be added to irrigation water.Apply a steady supply of nitrogen to the plantduring fruit set to produce greater yields. NewMexico growers often use 150 lb of urea per acrewhen plants are thinned. While plants develop firstfruits, analyze plant tissue samples to keep nitrateconcentrations in the plant stem and petiole between 7,000 and 8,000 ppm.High-yielding or early-setting crops may benefitfrom a third nitrogen application. However, toomuch nitrogen can over-stimulate growth, producing large plants with few early fruits. During highrainfall and humidity, extra nitrogen delays maturity, results in succulent late-maturing fruits, andincreases the risk of serious plant or pod rots.PLANTINGChile is a warm-season crop that requires a long,frost-free season to produce good-quality, highyields. Chiles do not thrive when temperaturesare below 60 F and can die from a light frost. Theoptimal period for direct-seed planting of chile isbetween March 1 and May 1 in southern New Mexico; plant 4 to 6 weeks later in central and northernNew Mexico. The early green crop will be readyfor harvest about 120 days after planting. The redGuide H-230 Page 2

crop will take about 165 days. Areas with a shortergrowing season may have little or no red chiles forharvest unless an early-maturing cultivar is planted.Consult with your county Extension agent orNMSU Extension vegetable specialist for additionalinformation on appropriate varieties for your area.A good stand can be achieved during optimalyears by planting 2 lb of high-quality seed per acre.Some growers plant up to 10 lb of seed per acre because extra seed compensates for plant losses fromcurly top virus, as well as other adverse factors suchas low germination of the seed lot.Center the seed row when planting in pre-irrigated soil. Use a harrow to loosen the soil and plantseed 3/4 to 1 inch deep. Capping (applying a firm,protective soil layer 3 to 4 inches high) can be usedto reduce water evaporation in furrow-irrigatedfields. Remove the cap with a dragging harrowwhen seedlings emerge (the crook stage). Carefullyadjust soil-removal equipment so a loose 1/4-inchlayer of soil covers the seedling after dragging; thisminimizes seedling damage and encourages rapidseedling emergence. Growers utilizing drip or sprinkler irrigation typically do not cap their chile seed.Chile seedlings are susceptible to salt until theyare 2 to 3 inches tall and growing rapidly. If soil hashigh residual salt or if irrigation water is salty, waterevery other row to push the salt front away fromyoung seedlings. Once plants have matured and areno longer as sensitive to salinity, switch to wateringevery row.Row Spacing and Plant PopulationThe most common row widths in New Mexico are30 to 40 inches. Growers often select row spacingto conform with requirements of other row cropsin their crop rotation. Narrower row spacing canresult in higher yields.Thin the plants when they are actively growing,are about 2 to 4 inches tall, and have 2 to 4 trueleaves. Delay thinning to ensure a good plant standif losses due to curly top virus, damping-off, or saltinjury are anticipated. New Mexican-type greenchile, cayenne, and jalapeños are usually thinnedto single plants spaced 10 to 12 inches apart. Redchile and paprika are typically thinned to clumps of2 or 3 plants spaced 6 to 8 inches apart.TransplantingTransplanting chile seedlings was common before1940, but today most commercial chile acreage inNew Mexico is directly seeded. Transplants are being tried again to promote earliness or when expensive hybrid seed is used.Transplanting has some advantages. It guaranteesa well-distributed stand of plants, reduces seed andthinning costs, and requires less cultivation and irrigation. The slightly older transplants are also lesssusceptible to salt damage than young, direct-seeded plants. Such economies help offset transplantand field-setting costs.Transplants are shorter than direct-seeded plantsand have more branches. This can be detrimentalwhen long fruits touch the soil, increasing the possibility of pod rot. Because of the effect on planthabit and a less-secure root system, transplants arenot as well adapted to machine harvest as directseeded stands. Anticipated benefits of earliness andhigher yields are not consistent, so growers shouldconsider other factors (seed amount, thinning costs,water amount, and late planting opportunities)when deciding whether to transplant.Transplant 5- to 6-week-old plants that are 6to 8 inches tall; space them 10 inches apart inthe row. Retain as many roots as possible beforelifting the transplant. Apply a high-phosphorusstarter solution to the soil during transplanting toaid in establishment.FRUIT SET AND DEVELOPMENTChile plants usually start flowering in mid-June insouthern New Mexico, with a single flower at thefirst branching node. Plants flower later in northernareas. Flower number doubles with each extra node.Fruits from early flowers are usually large and havegreater red color content at maturity.Fruits do not set when mean temperatures arebelow 55 F or above 95 F. However, flowers dropwhen night temperatures are above 75 F. Fruit setmay be stalled if temperatures rise above 95 F afterseveral flowers have set and fruits are developing.This causes a split in the fruit-setting continuumand is called a split-set. Early yield is determined byfruits developing before the onset of hot weather.Delay in fruit set can reduce yields and also causesfruit to set high on the plant, which makes plantsmore prone to wind damage as they mature.Guide H-230 Page 3

Chiles usually grow to full pod lengthin 4 to 5 weeks; pod weight increases asfruit walls thicken. Fruit normally reaches the mature green stage 35 to 50 daysafter the plants flower.IRRIGATIONChile needs 4 to 5 acre-feet of water between planting and harvest (Figure 2).Up to 70% of the water absorbed byfull-canopy chiles is removed from thetop 1 foot of soil. Optimal irrigationtime can be determined by testing soilmoisture in the root zone by touch orwith moisture sensors, or by computerpredictions.Irrigation volume varies with theamount of plant foliage, wind, sunlight,Figure 2. Test plots of new chile varieties being irrigated at the Fabiantemperature fluctuation, and relativeGarcia Research Center in Las Cruces, NM. (NMSU photo by Robert Yee)humidity. Watch developing plant leavesto estimate how often to irrigate. During hot, dryis not labeled for chiles. All large processors preing conditions, expect swiftly growing plants tosample chile fields to ensure that there are no traceswilt late in the afternoon, even the first day afterof non-approved chemicals and that residues ofirrigation. Wilting signs begin to appear earlier insubstances allowed for chile are within acceptablethe day as soil dries. Irrigate when plants wilt inlimits. Consult your county Extension agent or anearly afternoon.NMSU specialist before using the chemical if thereIrrigate less often when plants are small. Applyis any doubt.water on a 5- to 7-day schedule between late JuneRoot-knot nematodes can cause serious yield lossand July, before summer rains begin. After thees. The primary nematode known to damage chilesrains begin, extend the interval to 7 days or more,in New Mexico is the southern root-knot nemadepending on rainfall amount. Do not water whentode (Meloidogyne incognita). Contact your countythe risk of summer rains is high. Decrease irrigaExtension agent or NMSU vegetable specialist fortion frequency at the end of the season to promoteinformation on soil testing and control measures forripening and to improve fruit color. Phytophthoranematodes if a problem is suspected.root rot disease can develop from water standing inCommon diseases that infect chile in New Mexa field for more than 12 hours, so a means of drainico include Phytophthora root rot, Phytophthoraing the field is critical.foliar blight, Verticillium wilt, Rhizoctonia rootrot, various viruses, and bacterial leaf spot. A goodresource publication on chile disease is NMSUPEST AND DISEASE CONTROLExtension Circular 549, Chile Pepper DiseasesFlea beetles, thrips, le