Transplanting may seem simple enough, but there are many variable that will determine if your plants will take off or become stunted once transplanted. Learn the ideal timing, pot sizes, and feeding methods below.
At this point, you should have some healthy pepper starts with a few sets of true leaves, now what?Depending on how early the plants were started, you can either up pot your plants into bigger containers, or if the weather is nice enough, you can plant straight into the ground/pot/bed. Pepper plants are frost-sensitive, meaning if temperatures get to close to 32°F, you could be waking up to some dead plant. One general approach for transplanting outdoors is to wait at least 2 weeks after the last risk of frost has passed. In the Portland Metro area, this can be a difference of a few weeks depending on where you live, so it is important to know your microclimate. Google will easily help you out! "Usda planting zones for (insert your area here)." Another approach is that peppers prefer their night time temperature to not drop below 55°F. They will survive below this but can become stunted if too cold as a result. I use the second approach.
I like to start my plants in 72 cell trays, and then up pot into either 2.5 inch or 3.5 inch pots. Once my plants have a few sets of their true leaves (2-4), I up pot in to the a pot. My primary reason for using 2.5 inch pots is spacial limitations. I grow hundreds of plants and need to maximize space in my greenhouse. If you have the space, opt for 3.5 inch pots. If you let your plants become too root bound, it will have a hard time adapting to its next home. If you transplant too early then the root system fill fall apart and will have to spend more time acclimating to its new home before putting energy into foliage growth
If your peppers live in your house before going outside, you'll want to do something known as 'hardening off,' which is getting your plants accustomed to the outside. They have it pretty nice inside not having to deal with mother nature. Once you're getting close to putting your plants outside, you'll want to put them outside for just a bit each day for a few days before you put them into their final home. Start with just a few hours then bring them back in. If it's really warm/cold, you will want to keep an eye on them and make sure they are not wilting. If they look unhappy, bring them back in. This process can take about a week. If you received plants from me, make sure to confirm if the plants had been hardened off or not, as it will depend on the time of year.
Once you're ready to transplant, try to disturb the root system as little as possible. Don't squeeze the sides of the container, just hold it upside down with your hand supporting the rootball and push in on the bottom of the container. Pull the pot off then grab the rootball. Place plants into their final location. It is ok to bury it up to its first set of leaves if you'd like, but not necessary. This can help support taller plants. Topdressing ( sprinkling powdered nutrients on to the soil around the base of the plant and gently working in) with some kelp meal would help greatly to reduce transplant shock and encourage root development. Powdered nutrients can be a bit slow acting, so I recommend also using some Liquid Kelp and Liquid Fish Hydrolysate at 1/4 the recommended dose for some fast acting stress relief and a boost.