Cover an old heating pad with plastic to protect it from water. Place the seed starting tray on the heating pad.
Fill the seed starting tray with sterile seed starting mix. Moisten with water. Turn the heating pad on the lowest setting.
Place one or two seeds per compartment on top of the seed starting mix. Some gardeners use tweezers to insert seeds into the soil. Barely cover with a thin layer of sand. Spritz with water to moisten. Cover the tray with the plastic lid or plastic wrap.
Hang a fluorescent light fixture 4 inches above the seed starting tray. Use high-intensity fluorescent bulbs to increase the amount of light emitted by the fixture. Attach to a timer so the light provides 14 to 16 hours of light daily.
Remove the lid or plastic wrap as soon as the seeds germinate. It may take up to two weeks, depending on the variety, for the pepper seeds to sprout.
Mist the seedlings gently to keep the mix damp, but not soggy, until the seedling have at least two sets of leaves.
Transplant the seedlings into 4-inch pots filled with a good-quality potting mix. Do not pick up the seedlings by the stems, instead use a soup spoon to carefully scoop the seedlings and roots out of the tray.
Move the light fixture up as the seedlings grow, keeping it 4 inches above the tallest plant.
Harden off the seedlings when they are 6 to 8 weeks old and night temperatures are above 55 degrees Fahrenheit. Place the flower pots outside in a sheltered area for an hour, then bring back inside. Repeat daily, adding an hour each day, for a week to 10 days. Once the seedlings are outside all day, it is time to transplant them in the garden.
Prepare the garden bed by digging up the grass and unwanted vegetation. Place on the compost pile.
Add a 3-inch layer of compost to the garden bed and dig it in, mixing well with the garden soil. Then rake the soil into 1-foot-wide mounded rows.
Dig a hole for each pepper plant in the top of the row, 1 foot apart. Remove the pepper from the flower pot and place in the hole. Backfill and tamp gently.
Insert a stake next to each plant and tie it to the stake using a soft plant tie. Add more plant ties as the plant grows.
Arrange a soaker hose or drip watering system along the row. Water when the top of the soil is dry to the touch. Fertilize with 5-10-10 fertilizer according to the manufacturer's directions.
Add a 4-inch layer of mulch to the garden bed, surrounding the mounded row to within 4 inches of the pepper plant stems. Mulch inhibits weed growth and helps the soil retain water.
Monitor your pepper plants for pests such as aphids, caterpillars, earwigs, slugs and snails. Kill aphids by spraying with soapy water. Remove other pests by hand and dropping into a bucket of soapy water. Pour the water and dead bugs onto the compost pile.
Harvest according to the seed packet directions. Different varieties of peppers and chiles are harvested when green, yellow, orange or red. For example, bell peppers are harvested at any stage between green and red. The longer a mild pepper like a bell pepper stays on the plant, the more vitamin A and C are concentrated in the fruit. Hot chiles are often allowed to ripen on the vine, then hung on a string to dry.