My first try at growing eggplants, but an experienced gardener. Eggplants started under lights, planted in warm soil. Healthy plants, good fruit set, young fruit purple but when about three to four inches long, fruit turns yellowish green. When roasted in skin, too bitter to eat. What caused this? Can any fruit be saved or should I just pull up plants? What advice have you if I want to grow more in future.
Eggplant that is harvested to late is quite bitter.
Verify the type of Eggplant you are growing, as some are quite small and should be harvested at small sizes.
Here is a link with more information.