Gardeners often place matchsticks in the soil beneath green peppers (Capsicum annuum Grossum Group) when setting them out to feed those plants’ love of sulfur. Because peppers prefer a pH between 6.0 and 6.8, the acidifying chemical does help provide optimum conditions for them, so their use isn't just an old wives' tale. The number of matches recommended varies from two or three per plant to an entire book (20) per plant. If you have other uses for matches, you can add a small amount of garden sulfur to each planting hole instead.
Peppers must have warm conditions to thrive, so don’t set them out until after the last spring frost. Wait until the soil temperature is 65 degrees Fahrenheit and nighttime temperatures have climbed above 55 degrees F., daytime ones above 70 degrees F.
If you started pepper plants indoors, begin taking them outdoors for a few hours every day. Set them in the shade at first, and gradually extend their outdoor time while moving them into more sun.
For the one or two weeks during which you are hardening the plants, lay black landscape fabric or black plastic over their intended bed to heat up the soil more quickly.
Plant peppers in full sun, in fertile, well-drained soil. First, make a 6-inch-deep hole, partially filling that excavation with 2 inches of compost and about 1/2 cup of 5-10-10 organic fertilizer. Work those amendments into the bottom of the hole with a trowel.
After removing the cover from a book of matches, place the matches atop the just-worked soil. If you prefer to use garden sulfur instead, add 1 teaspoon of it. To avoid shocking the seedling, cover the matches or sulfur with 1 to 2 additional inches of soil so the amendments don't come in direct contact with the plant until it is well-established. You then can set a pepper in the hole, loosening its roots if they have become matted together, and positioning the plant slightly deeper than it grew in its container.
After filling in the soil around its roots, pat the soil down and water it well. If you wish to set out more than one pepper, space the plants 18 inches apart and their rows 24 inches apart.
Keep the peppers’ soil damp while they are becoming established, providing them with at least 1 inch of water per week, via rain or irrigation. To help maintain their soil’s moisture and discourage weeds, mulch the plants with up to 2 inches of a light organic material such as straw or shredded dead leaves.