When the directions on the back of the paper seed packet says, “sow in full sun,” don’t always believe it.
Seed distributors and gardeners from cooler parts of the country cannot imagine the intensity of the summer Arizona sun!
A thermometer placed three inches below my sandy virgin-desert soil reveals temperatures that sometimes exceed 145 degrees. Lots of organic compost helps to alleviate some of this in the garden. However, plants often cannot withstand the combined effect of solar radiation from above and hot earth below.
Sowing seeds in containers allows me to protect the guys beneath a bit of shade during hot weather. Then I can move the pot into the light during overcast days or when the season changes. Don’t alter the environment abruptly, though, because it can shock the plant. Also check the moisture of the soil regularly because containers dry out quickly.