Why are my bell peppers bitter? (Gardening question)

Sorry I keep asking lame-brained gardening questions, but this is the first time I’ve really had the room to grow a nice vegetable garden, and things keep going wrong!

I’ve got a bell pepper plant that’s really working overtime on production. I harvested one the size of a freaking softball for a salad last week, and I noticed it had thinner walls than the supermarket kind and tasted a little bitter. Well, I tried another (baseball sized) one yesterday, and it was very bitter. You know how peppers often have a little bit of a bitter under or aftertaste, and that’s normal? Well, this one was like all bitter and no pepper taste. I’m very concerned - are all my peppers on that plant a waste? What could be wrong with it?

Unfortunately, I don’t know what cultivar this one is - it was an impulse purchase at a big box store and just said “bell pepper” or “sweet pepper”, I forget which. At the other end of the garden I have a japaleno plant and another bell (California Wonder, I think? Anyway, a named variety, at least). Neither of them are at the big-enough-to-eat stage - nowhere near it, actually.

So, two questions - what’s wrong with them, and is it too late to fix? And should I do anything to the other two plants to prevent it on them? I’m so disappointed!

If you’re eating them green, they may not be ripe yet – try leaving them on the plant a little longer and see if they turn red (or yellow, or orange, or purple…)

Disclaimer: I suck at big peppers. Something always seems to go wrong with them and I get tiny crops. I blame heavy soil.
The usual reason for thin walled peppers is a water deficit. That’ll make them bitter too.
How are your tomatoes?

The worst-hit tomatoes haven’t really grown (one plant in particular) but the others are doing fantastic - I’ve got green tomatoes the size of a toddler’s fist. Unfortunately they’ve gotten away from me and are about to take over my yard - if I stop posting, indeterminate tomatoes got me. My garden in general is full of sex - everything’s blooming or fruiting. Love is in the air!

They’re getting plenty of water - in fact, for a while there along with those deficient tomatoes they were getting too much water. I’ve fixed that problem, though. Maybe the tomatoes were sucking up all the water? This particular plant is near them.