We just had an early September snow (two nights below freezing) here in Colorado. I did get some cover over my beds to keep the snow off the plants, but it was much to big to really work as a greenhouse so it still got cold in there. My bell peppers and even the habaneros seem to be alright, but the ghost peppers are not. I've just got one plant, and it seems like all the shoots which have fruit on them have dropped all their leaves, though there are still leaves on the 1 or 2 stems that had no fruit. My basic question is, should I cut my losses and harvest now and they just won't be as spicy, or is it alright to leave them out and see what happens (the fruit are all still green and I would have guessed they needed another month to fully ripen)? The forecast doesn't show any cold temperatures anytime soon and we get lots of sun, but I guess I'm just worried they might rot on the vine if the plant is dying.
"I did get some cover over my beds to keep the snow off the plants, but it was much to big to really work as a greenhouse so it still got cold in there." — If you know there's going to be a short-term frost, spraying the plants with water as late as possible will help prevent damage. It requires a lot of heat transfer to freeze the water, and the plants won't experience below 0° (that 32° in American) until the water on them has frozen, and by that time the air might be warming up again.– Ray ButterworthFeb 23 at 14:54
Sad to say, you probably are stuck with the consequences of Colorado's very early and very cold first frost this year, and the ghost peppers are done. By now, several weeks later, it's evident, and you can correct me if I'm wrong. If the leaves are dead the fruit won't ripen, so harvest what you can use in its present condition and compost the rest.
Sometimes a light frost will kill only the outer leaves of a plant that is sufficiently big and bushy to have retained some warm air toward its center. In that case the inner part of the plant can continue to limp along and mature some fruit until the harder frost arrives. Mostly I've seen that on tomatoes and less so on smaller eggplants or peppers, however.
1I ended up leaving them to see what would happen, and just picked about half the peppers today. It's definitely not a happy plant, though since it's been fairly warm and sunny since that frost I think it kept them from getting worse and few leaves have started growing back. Other than one rotten fruit, the rest is basically all orange now (was green during the frost). I don't think it will go full red since a couple of them are developing some sort of sores, but I'll see how much they ripen off the vine and see how hot they get. Building a greenhouse for next year! Oct 7, 2020 at 18:59
1I am pleased to stand corrected about the fruits ripening. I'm not sure the extent to which it was simply time and they would have ripened on the kitchen counter versus inputs from the plants, but if the plants were trying to grow more leaves, they definitely weren't dead just yet. Good luck with the greenhouse, and plan for it to withstand hail! Oct 8, 2020 at 19:43
From my observation -
Once harvested, the chilies (peppers) will turn from green to yellow and maybe even red. But this will not increase the amount of heat in them.
The only way to increase the heat is for them to ripen on the plant. They really start to pick up the heat once the seeds are ripening inside.
Let chili peppers age on the vine The longer a hot pepper ages, the spicier they become. The amount of capsaicin in the fruit increases over time, so if you can wait until those green jalapeños turn red, then you’re in for a much spicier experience.
From How To Grow Hotter Peppers
Ripe pods are sharper with the same chili. Many chilies turn red, some remain yellow or orange. If the chili ripens longer, more capsaicin can be produced. With overripe fruits, however, the content sings again. Caution: a green Trinidad Scorpion burns more devilishly than a red Cayenne
And again Making chili plants hotter
Picking half of them was probably a good idea - hedging your bets.