Wait until a few weeks after the danger of frost in your area to plant chili seedlings outside. You can grow seedlings in the ground or in a container and still end up with a decent yield. If you have grown the seedlings indoors, you will need to harden them off before planting outdoors. Plant the chili seedlings in an area that gets full sun and is protected from harsh winds. Once planted, protect the young seedlings from pests and damage.
Seedlings should be at least six weeks old before you plant them but not older than ten weeks. If the plants have started to produce flowers, which will develop into chili peppers, pinch them off. The plant needs to develop a strong root and stem system before it can begin to produce fruit. It cannot develop a strong root system until it has been planted.
Up to two weeks before you are going to plant the chili seedlings, begin hardening them off. Chili seedlings that begin life indoors will suffer shock if suddenly planted outside, where it is usually colder than the indoors and the weather is harsher. You need to slowly introduce the seedlings to the elements.
Set the seedlings outside in a protected area for a small amount of time to start. Leave them outdoors for an hour on the first day and then bring them back in. Continue to leave them outside for longer and longer periods of time until they are spending all day and night outside. You are then ready to plant the chili seedlings in the ground or container.
Use a container that's about 12 inches (about 30 cm) deep for the seedlings. If you're planting in a container, you need to use container soil, not garden soil. Dig a hole that's twice as wide as the root ball of the seedling and then set the seedling in it. Fill in with container mix or garden soil, depending on where you are planting. You can add a handful of compost or fertilizer to the soil when planting.
Chili peppers thrive in full sun, so choose a spot in the garden that gets at least six hours of sun daily. If you are planting in the ground, give each plant enough space. Don't plant the seedlings closer together than 12 inches (about 30 cm). Plant only one seedling per container.
You may want to slide an empty paper towel roll around the seedling's stem to protect it from insects that will cut through the stem. If rodents and cats are a problem, protect the seedling by wrapping chicken wire around the container or area. You can also use pesticide sprays to kill any bugs if you wish.