Hot peppers do well throughout the summer. During the temperatures of more than 100° F, in a south facing garden, peppers themselves may get some sun scalding and plant growth may slow down temporarily. Even then the plants will continue to bloom and produce peppers. As the rain arrives and the temperature drop below 95°F after mid August they go into overdrive.
Pre-planning and growing the plants during the right time is one of the most important factors in successful gardening. Fall and winter is a good time to make plans for the peppers for next spring. Browse the seed catalogs, select areas where peppers can get at-least 6-8 hours of direct sun, add compost to the ground where peppers will grow in spring and sow the seeds indoors in January to February.
If you are a beginner gardner, growing chilies from nursery transplants is best as starting peppers from seeds may not always be a success. However if you have some basic experience growing any vegetable it is worth trying the interesting varieties of peppers available at the seed companies.
NMSU in Las Cruces, NM has a chili pepper institute and there are several varieties sold on their online store that are very well adapted to this area.
It takes at-least 8 weeks for the transplants to be ready from seeds. Seeds have to be started in mid to late January for the plants to be ready for transplant in mid March to early April. They have to be started indoors in a well lit area near a window as it is too cold for seeds to germinate outside in winter. If you start seeds later, say in March or April, by the time transplant are ready it will be the hot month of June. These small plants will not have a strong root system at this stage and it will be difficult for them to withstand the hot windy summer. Therefore it is very important to start seeds early, no later than mid February. If that time window is missed it is then best to buy the transplants directly form nursery as the success rate of a good chili produce will decrease due to a late start. Mid April is the latest to put transplants in ground. Follow the weather forecast regularly during the March-April nights as El Paso can get frost during these months. Plants could be covered with a frost protection blanket on cold nights.
Always add compost to the soil to enrich it prior to planting peppers and dress it with some more compost 2-3 times during the growing season. Drip irrigation works best as with most plants. Plants should not be sprayed from top as it can cause salt deposits on the leaves and peppers.
Bell peppers may perform less well (specially south facing garden) than hot chillies during the hottest months but regain their shape and flavor as the temperature lowers after August.
Peppers are extremely productive and having 3-4 plants can gives good harvest for 4 people.
Pepper plants perish with the first freeze usually in November.
A problem pest in desert soils is the root knot nematode. It is a microscopic organism that infects the roots of many plants and stunts the growth of peppers. There is no good cure for these resistant pests. The best method is to rotate the crop (do not grow pepper in the same area for two consecutive years). Move the pepper plants to different plant bed next year. Also, keep your soil rich with compost and other organic matter. This will encourage the beneficial microorganisms an reduce the root knot nematodes.
Peppers grown in containers with soilless mixtures will not be affected the root knot nematodes.