Over the years, we've gravitated to planting the majority of our peppers in pots. We're a small-scale grower, usually growing around 40-70 plants in a given year. Below are the main reasons why we like to grow peppers in pots...
Though, growing peppers in pots does come with a few drawbacks...
If grown in a container, the container's size (and sunlight) will generally be the limiting factor in keeping a plant from reaching its potential. When planted in too small of a container, pepper plants become root-bound and require very frequent watering.
Typically, your garden store or seed seller will recommend a minimum planting distance. Based on the variety, that'll usually range from 2-4 feet. Use the table below as a guide for converting plant spacing to a proper pot size.
We typically add straw (or lawn clippings) and homemade compost to our potted pepper plants. The compost provides many nutrients near term as well as beneficial microbes, while the straw/grass will decompose over time to give the plants an extra kick in the longer term. It's also beneficial as straw is cheap and the compost is free, reducing the amount of potting soil we need to buy.
As the straw decomposes, the soil level will drop. When completely consumed (in about 1-2 months), you can add another batch of straw, bone meal, compost and soil to top off the container, if desired. We'll usually do this if we see signs of the plant becoming root-bound.
The past couple of years, we switched to buying our soil in bulk from Soil3. We mixed the 27 cubic feet of organic soil they provide with 3 cubic feet of peat moss and 8 cubic feet of perlite, saving a total of $50, or 16%, compared with buying potting soil by the bag.
The peat moss helps to lower the soil's pH, making it more acidic, which is good for pepper plants, and additionally, helps to balance the soil's water retention and drainage. The perlite also helps to balance drainage and water retention as well as capturing oxygen and keeping the soil from compacting too much.
Not only does this save us money, it's a higher quality of the soil. As an added bonus, it saved us multiple trips to our local home improvement store for what would have been a back-breaking 23 bags of potting soil!
Using the above ingredients, we build our pot as follows...
We like to put the straw and compost in the middle layer so the plant grows down to it and to reduce weeds, grasses and other volunteer plants that would inevitably sprout from the straw and homemade compost. We also bury the bone meal at the compost/straw layer and below. We've found that putting the bone meal at the upper layer tends to attract animals that will dig up the soil and potentially (usually) damage young plants.
Previously after a growing season, we'd empty our pots into our raised beds and use new potting soil the following year for our potted peppers. This annual flush-and-refill is a decent amount of work and a significant expense.
The soil3 website claims its soil has enough nutrients to last up to 4 years in raised beds without fertilizer. In using their soil, it does appear to be high quality, and we'd like to see if we can reuse the same soil for another year.
Though, we're going to give it some help in an attempt to replenish lost nutrients. With the initial straw and compost layer, our pot's soil level does compress significantly through the growing season – typically leaving the top 1/3 of the pot empty. After pulling the plants in fall, we're going to fill that top layer with compressed straw, compost, bone meal and rock dust. After which, we'll top off with a couple of inches of soil as a weed barrier.
By spring, we're hoping this will return many of the nutrients lost during the previous growing season. Our main concern with soil reuse is it may allow the mosaic virus or other pathogens to remain in the soil and more easily affect next year's plants. We plan to plant control pots to test.