This has been one of the hottest if not the hottest summer on record in the mid-west. Temps have gotten as high as 115 F, and we had several weeks with little to no rain and temps in the 100s every day. To keep the luffa alive, I watered every day or every other day. The one I grew on the south side of my fence seems to be doing the best.
All of the fruit from this plant is growing on vines that poked through to the north side of the fence (picture above), which I found interesting. This one is almost as big as a baseball bat.Here's what this plant looks like on the south side of that same fence. There are plenty of leaves and many flowers, but no fruit on this side.
This plant suffered and the leaves withered from one day when I forgot to water in 100 degree temps. It does have one luffa fruit/gourd growing on it, and it was the first plant to start fruiting. It is growing on the north facing side of a fence.
And one final update: We got an early snowfall in October that killed all of the leaves on the plant. I had about 20 luffa, but only 3 of them were ripe enough to peel well and remove the sponge easily. If I had just a few more weeks before that first snow, I might have gotten 20 sponges from 2 plants.
See the other posts about my attempt to grow luffa in USDA zone 5:
Sprouting seeds
Plants in May