Planting Timeline
Showing dates for Japanese Long in USDA Zone 7
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Japanese Long · Zones 4–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 4 | March – March | May – June | — | July – September |
| Zone 5 | February – March | May – June | — | July – September |
| Zone 6 | February – March | May – June | — | July – October |
| Zone 7 | January – February | April – May | — | June – October |
| Zone 8 | January – February | April – May | — | June – November |
| Zone 9 | December – January | March – April | — | May – November |
| Zone 10 | November – December | February – March | — | April – December |
Complete Growing Guide
Start your Japanese Long eggplant seeds indoors 8-10 weeks before your last frost date, as these warm-season plants need a long growing season to reach their potential. Sow seeds ¼ inch deep in seed-starting mix at 75-85°F for optimal germination, which typically occurs within 7-14 days. Keep seedlings under grow lights or in a south-facing window, maintaining soil moisture without overwatering.
Prepare your planting site by working 2-3 inches of compost or well-aged manure into well-draining soil with a pH between 6.0-6.8. Unlike globe eggplants, Japanese Long varieties benefit from slightly more nitrogen early in the season to support their vigorous vertical growth. Wait until nighttime temperatures consistently stay above 55°F and soil temperature reaches 65°F before transplanting—typically 2-3 weeks after your last frost date.
Space transplants 18-24 inches apart in rows 3 feet apart, as these plants can reach 3-4 feet tall and spread 2 feet wide. Install sturdy stakes or cages at planting time, since the long, heavy fruits will pull branches down without support. Mulch heavily around plants to retain moisture and suppress weeds, keeping mulch 2 inches away from stems.
Feed with a balanced fertilizer (10-10-10) at transplanting, then switch to a lower-nitrogen, higher-phosphorus fertilizer once flowering begins to encourage fruit production over excessive foliage. Side-dress monthly with compost or apply liquid fertilizer every 2 weeks during peak growing season.
Avoid the common mistake of letting soil dry out completely between waterings—Japanese Long eggplants need consistent moisture to prevent fruit from becoming tough or bitter. However, don't keep soil soggy, as this invites root rot. In hot climates (zones 9-10), provide afternoon shade to prevent sun scald on the tender fruits. Northern gardeners in zones 6-7 should consider black plastic mulch or row covers early in the season to boost soil temperature and extend the growing period.
Harvesting
Harvest Japanese Long eggplants when fruits reach 8-12 inches long and maintain their glossy, deep purple color with tight, smooth skin. The key indicator is skin that springs back when lightly pressed—overripe fruits will feel soft and have dull, wrinkled skin with visible seeds inside. Unlike globe varieties, these elongated fruits should feel firm but not rock-hard when ready.
Test readiness by gently pressing your thumbnail into the skin near the bottom of the fruit. If it leaves a slight indentation that quickly disappears, the eggplant is perfectly ripe. If your nail easily punctures the skin or the indentation remains, wait a few more days. Harvest in the morning when fruits are cool and fully hydrated for the best texture and longest storage life.
Cut fruits from the plant using sharp pruning shears, leaving a 1-inch stem attached. Never pull fruits off, as this can damage the plant and reduce future yields. Regular harvesting every 2-3 days during peak season encourages continued production. Each plant typically yields 8-12 long fruits over a 6-8 week harvest period.
Storage & Preservation
Store freshly harvested Japanese Long eggplants at room temperature for up to 5 days—refrigeration causes the tender skin to pit and the flesh to become bitter. If you must refrigerate, wrap individual fruits in paper towels and use within 3-4 days. These thin-skinned eggplants don't store as long as thick-skinned globe varieties.
For preservation, slice into rounds and salt for 30 minutes to draw out moisture, then freeze in single layers on baking sheets before transferring to freezer bags—frozen slices work perfectly for stir-fries and curries. Japanese Long eggplants also excel when pickled using traditional Asian brining methods with rice vinegar and miso. Avoid canning due to their low acidity, but they dry beautifully when cut into thin strips and dehydrated at 135°F for 8-10 hours, creating concentrated strips perfect for reconstituting in soups and stews.
History & Origin
Japanese Long eggplant, known as 'nasu' in Japan, represents centuries of careful selection by Japanese farmers who prized tender, non-bitter varieties perfect for their cuisine. This heirloom variety likely descended from wild eggplants that traveled from India through China to Japan over 1,000 years ago, where Japanese gardeners developed the characteristic long, slender shape through generations of seed saving.
The variety gained popularity in Japanese temple gardens during the Edo period (1603-1868), where Buddhist monks cultivated vegetables for their plant-based diet. They specifically selected for the sweet, mild flavor and tender skin that required no peeling—qualities that made it ideal for delicate preparations like tempura and nimono (simmered dishes).
Japanese immigrants brought these seeds to America in the late 1800s and early 1900s, where the variety remained largely within Japanese-American communities until the broader interest in Asian vegetables emerged in the 1970s. Today, Japanese Long remains treasured by home gardeners who appreciate its superior taste and cooking qualities compared to the sometimes bitter globe eggplants common in Western markets.
Advantages
- +Never requires peeling due to exceptionally tender skin that breaks down during cooking
- +Completely bitterness-free flesh even when fully mature, unlike globe varieties
- +Cooks 40-50% faster than thick globe eggplants due to slender profile
- +Highly productive with 8-12 fruits per plant over extended harvest period
- +Excellent natural resistance to flea beetle damage compared to thin-skinned European types
- +Perfect portion size for 2-3 people without waste
- +Superior texture retention in stir-fries and quick-cooking methods
Considerations
- -Shorter storage life than thick-skinned globe varieties due to tender skin
- -Requires staking or caging due to heavy fruit load on relatively slender stems
- -More susceptible to sun scald in intense heat without adequate foliage cover
- -Takes longer to mature than early globe varieties (70-80 days vs 60-70)
- -Can become overripe quickly once ready, requiring frequent harvest checks
Companion Plants
Plant Together
Basil
Repels aphids, spider mites, and hornworms while potentially improving eggplant flavor
Tomatoes
Share similar growing requirements and pest management strategies as nightshade family members
Peppers
Compatible nightshades that benefit from similar soil conditions and watering schedules
Marigolds
Repel nematodes, aphids, and whiteflies while attracting beneficial insects
Nasturtiums
Act as trap crops for aphids and flea beetles, drawing pests away from eggplant
Oregano
Deters pests like aphids and spider mites with its strong aromatic compounds
Hot Peppers
Natural pest deterrent that repels many insects harmful to eggplant
Catnip
Repels flea beetles, ants, and aphids that commonly attack eggplant
Keep Apart
Black Walnut
Produces juglone toxin that severely stunts or kills nightshade family plants
Fennel
Releases allelopathic compounds that inhibit growth of most vegetables including eggplant
Corn
Creates excessive shade and competes for nutrients, reducing eggplant fruit production
Pests & Disease Resistance
Resistance
Good resistance to common fungal diseases
Common Pests
Flea beetles, aphids, spider mites, thrips
Diseases
Verticillium wilt, fusarium wilt, bacterial wilt