When to Harvest Eggplant:
• Harvest eggplants when they are firm and glossy and big enough to eat—about one-third their maximum size.
• To test eggplant fruit for maturity, press the fruit with your thumb; if the flesh springs back it’s green and not ripe; if your thumb leaves an indentation, the fruit is overripe; the best tasting eggplant will be in between.
• A just ripe eggplant when sliced will have soft, well-formed but immature seeds; an immature and unripe eggplant will have no visible seeds; an overripe eggplant will have hard, dark seeds. (Seeds forming inside the fruit cause the skin to go from shiny to dull.) Both an under-ripe and overripe eggplant will be bitter tasting.
It is better to harvest eggplant just before its ripe than to wait too long.
How to Harvest Eggplant:
Cut eggplant fruits from the plant with a garden pruner or sharp knife. Leave one inch of green stem attached to the fruit. Eggplants are very difficult to pull away from the plant by hand; doing so can damage the plant.
How to Store Eggplant:
Store eggplants in a room with high humidity to preserve texture and flavor and avoid dehydration. The optimal temperature for storing eggplant is 55°F (13°C). At 55°F, eggplants will keep for 1 to 2 weeks.
You can store eggplant in the refrigerator but not cooler than 50°F (10°C). Rinse the fruit clean, pat it dry with a kitchen towel, and place it in a perforated plastic bag to keep it from drying out. (Refrigerators are cold and dry, not humid.)
If exposed to temperatures below 41°F (5°C), eggplants will develop surface pits, bronzing, brown spots, and decay.
Eggplant fruit discolors rapidly when cut open, so it’s best to use it immediately once sliced.
Avoid storing eggplants with apples or tomatoes; ethylene (a natural plant hormone released in the form of a gas) given off by those fruits will cause eggplants to brown and decay.
More tips: How to Grow Eggplant.