How hot has it been where you are? I believe peppers will not set fruit in hot weather. Like tomatoes the pollen is not viable when night temperatures exceed a certain amount. I can't remember exactly what it is. I think in the upper 70's for peppers. I am sure one of the veteran farmer/gardner's knows the exact temperature.

Here is a link that might be useful: Adventures in Agriburbia

The condition called 'Blossom Drop' is the best place to begin. I linked the FAQ on it below and the search will also pull up lots of discussion about it. Note all the various causes of it and adapt accordingly.

Then please note that 4 pepper plants in 1 Earthbox will be very problematic. I also use Earthboxes for many things, including pepper plants, in addition to my in-ground gardens and while 2 plants work great, 4 is over-crowded and puts excessive demands on both water and nutrients.

Dave

Here is a link that might be useful: Blossom Drop FAQ

I don't know, the the night temperatures have been in the high 50s, low 60s for the past two weeks so I'm not sure that weather is my problem. Then again, the in-ground tomatoes are not setting as much as they normally do; we have huge green vines with lots of blossoms but few actual tomatoes. I've been shaking the tomato plants the past few days to see if that will make a difference. The squash, green beans, and cucumbers are doing quite well. If it's not the weather, should I try shaking the peppers too?

FWIW, I did add some Agricultural Lime to the planting mix when I planted out the peppers (they're in a homemade Earth"Tainer", which is appreciably larger than an Earthbox). I'm also due to get delivery on some Calcium Nitrate today, which I plan to add to the water resevoir as a "snack".

Athena

How about day time temps and % of humidity? They are more important than night temps.

But from your descriptions it is beginning to sound more like an issue of excess nitrogen - one of the primary causes of blossom drop. Terms like big, healthy-looking, huge green plants with lots of leaves, etc. are all potential indicators of excess nitrogen. Plants need it sure, but excess amounts of it equals great plants with little or no fruit production.

Timing of nitrogen applications also plays a role as it can kick a plant out of fruit-set mode into a growth spurt instead.

Just some thoughts to consider.

Dave

The daytime temperatures haven't really been hot -- mid-eighties for the past couple of weeks with mid-fifties humidity.

I've been suspecting excess nitrogen in the case of the tomatoes after using an 18-18-24 "tomato fertilizer" for 3 consecutive weeks (following the label). I stopped when they got so big and now I'm afraid they've been ruined for the season.

The peppers though haven't had anything beyond the 4-5-3 that was put in the strip when I planted. I wasn't planning to add actual fertilizer for a while.

Athena

Athena,

Your season, especially in zone 10, is far from over. So, your toms are definetly not ruined for the season. Just switch to a lower N fert for them and I'm sure they will produce for you. Your crop may just come in a bit later in the season compared to others in your area.