My peppers were looking like this also earlier this year. I found something at Farm&Fleet called "NuStraw" which is straw that is for gardens - it's cut into about 2" or less pieces and I've not yet seen one seedhead or stalk! I've had terrible problems with straw mulch in our gardens in the past - think wheatfield instead of green beans - but thought I'd give this a try. Thus far, I'm very impressed. I put about a 2" layer down around all the peppers and the yellowing of the leaves disappeared. It's seemed to help the peppers in retaining both heat and moisture, which they need, so I expanded the "NuStraw" into the tomatoes too. As it's finally warm enough for both these crops here, they're taking off - whether from the mulch layer or the heat, I'm not sure!