I was given a birdhouse gourd seedling and wow do those things grow. I'm growing butternut (C. Moschata), zucchini (C. Pepo) and cantaloupe (C. Melo) in the garden as well. I'm not sure what species the gourd is and if it will cross with my other squashes. I only need to save seed this year from the zucchini and I'd like to save these gourd seeds as well.
Birdhouse gourds are in the Lagenaria genus. They will not cross with zucchini, butternut, or cantaloupe which are in different genera.
Birdhouse gourd seeds have a reputation for poor germination. Germination can be enhanced by harvesting seeds more than 60 days after pollination, then fermenting them anaerobically in warm temperatures for 10 days.
Awesome, thanks Joseph! I haven't seen a flower yet so 60 days will put me well into September where frost is likely. Can the fruit handle a light frost as the seed keeps maturing or should I harvest before frost nips them? My primary goal is gourds for bird houses, secondary is the seeds.
My strategy is to wait to harvest until the leaves are killed by frost. The first frost rarely damages the fruits or seeds. Then I store them in the greenhouse for a month or so before harvesting the seeds. I'm certainly not keeping track of when flowers are pollinated.
A lot of people leave birdhouse gourds to rot in the field until spring. Then harvest the seeds. So they have freeze/thawed through the winter. I suspect that's part of the reason they have a reputation for poor germination. Doesn't matter if I get 10% germination if I'm only growing seed for myself, family, and friends. We just plant thickly, then thin.