Not sure where you are located, but 120 days should be plenty. They don't need continuous hot weather. I've grown great bell peppers in a 5 gal bucket in northern NY State. What soil are you using?

Thank you for responding to my post.

The native soil where I live is horrible, so I typically grow them in containers and/or raised beds. I've read that supposedly peppers like a soil that is (for lack of a better term) 'light and fluffy'?

I can make that soil mix, but what would I need to achieve a soil of that consistency, and in what quantities with each ingredient?

Here are two mixes I've found regarding soil mixes for raised beds; which would be the best mix to use for peppers? Also, should it be spaghnum peat moss or just regular peat moss?

30% peat moss, 30% coarse vermiculite, 30% compost, and 10% sand.

50% top soil, 40% compost, and 10% sand

Also do you know what causes purple peppers to be so dark in color (almost black).

Those soil mixes aren't bad, but you might be able to do a bit better. Please check out this thread in the Containers forum. It's a bit overwhelming at first. I use the recommended soil mix and have had great results.

https://www.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention-xxii#n=977

Yes I have tried using that soil mix before (the 5:1:1 mix) but unfortunately I cannot find pine bark fines that are fine enough in consistency. I can get pine bark fines where I live, but I they're too coarse/big.

I can order pine bark fines on the internet, but it's really expensive. Also not to be rude, but the soil mix (the 5:1:1) you're suggesting is for containers; I'm using raised beds, which while similar to container gardening, isn't the same thing.

Bells seem to be the most difficult pepper to grow. I would guess you are probably trying too hard. A good variety in 5 gallon container filled with any good potting soil should do well. after basic success you can fine tune.

Purple bell varieties come in many shades from pale to almost black Lilac - Merlot)

Sorry, you mentioned using containers in your op.

I agree about bell peppers being disappointing. I have done better with the "Italian" sweet peppers, with tapered rather than blocky bottoms.

This might help.
Types of sweet peppers

Like cubanelles. What varieties have you tried?

I have the same issue... I am thinking it is our cold summer nights here. This year I am going to try something like this:

https://www.amazon.com/dp/B00CPHV4QA/?coliid=IX8OLVWSQK97P&colid=1TO724PO5Z6FX&psc=0&ref_=lv_ov_lig_dp_it

over one or two of them and see if that helps.

I had some really bad experiences with 511... don't recommend it unless you are 100% sure you can get the right bark and you live in a humid climate where water retention is a big problem.

I agree with nanelle about trying sweet peppers other than bells that ripen earlier and set more fruit than bells. Carmen, Escamillo, Ajvarski are a few that I grow. If you want bell shaped peppers for stuffing you can still grow them and pick them green and then grow these bulls horn shaped peppers for eating fresh.

Many years ago I could not grow bell peppers, they didn't make it even till blossom, some of them died for unknown reason or had been eaten by deers. I gave up. Those years I was building several raised beds with my own soil mix in them. I didn't buy any bagged amendments from stores, but I 'm blessed to live in forest land; so, I can find everything near house.

My native soil is very bad - different kinds of clay most of it. I mixed it with UCG (it is free and endless quantity from starbucks) and shredded fall leaves, shredded papers, kitchen scraps. I did it religiously, for several years, added composted leaves to beds every season. First year of that mix I planted potatoes and calabasa, they did great, I'd got 14 pumpkins from 2 plants.For next years I planted tomatoes there, they did great too. Then I decide to try peppers again. I planted seeds from a store bought pepper which taste I liked. The peppers did wonderful! Every 2-3 days I picked big popcorn bowl of sweet fleshy peppers. I fed my neighbors with them till frost. ( In fall, when nights get cool, they didn't slow, still flowered and set new fruits).

I didn't fertilized them , just watered with rain water.

Actually, if you put uncomposted greens in your soil, you DID fertilize, though the risk in doing that is that you applied too much nitrogen. Uncomposted stuff can be a little dangerous in that regard.

Amy, are they getting enough sun? Mine haven't grown well when they don't get at least 8 hours of full sun.

Uncomposted enough greens were in the mix only the first year of the raised beds. And that year I planted pumpkins and potatoes there, they love to grow in the composting pile for what ever reason.

When I planted tomatoes and peppers 2-3 years later , composting was pretty much done, soil mix has amazing texture , many worms, plants were happy.

My point is you don't have to order online or buy in stores anything to get good enough soil mix for happy peppers.