De 18 Jours is an heirloom French radish variety whose name tells its greatest promise: eighteen days from seed to harvest. Under ideal conditions, you'll have crisp, juicy roots ready for the table in less than three weeks, making this one of the fastest radishes you can grow. The roots are round to cylindrical with striking red skin blushed with white tips, classic French breakfast styling. This variety has been grown under glass in Europe for generations to extend the season, and it thrives in cool weather between 50 and 75°F, making it particularly rewarding for spring and fall planting.
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The speed alone sets De 18 Jours apart: you'll see sprouts in just 3-6 days and harvest mature roots by day 18 under optimal conditions. Round to cylindrical roots with deep red shoulders and cream-colored tips deliver the crisp, juicy flesh that made French breakfast radishes famous. This old variety germinates reliably, grows best in cool seasons, and because it's frost-hardy, you can push plantings into shoulder seasons when other crops are fading.
These radishes are sliced thin and eaten fresh, often with a pinch of salt and a small pat of butter in the French tradition. Their crisp, juicy texture and mild flavor make them excellent in salads, vegetable platters, and composed dishes. Because of their rapid maturity and compact root size, they're also popular for succession planting in containers or small garden spaces where you want continuous harvests rather than one large crop.
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Direct sow De 18 Jours radish seeds 1/4 inch deep in loose, well-draining soil. Space seeds 2 inches apart in rows or broadcast throughout a bed, thinning to final spacing as seedlings develop. Sow in early spring 2-3 weeks before the last frost, and again in mid to late summer for a fall crop. This variety sprouts quickly in 3-6 days and reaches harvest in 18 days under ideal cool conditions (50-75°F).
Begin harvesting De 18 Jours radishes at 18 days after sowing, though you can harvest earlier if you prefer smaller, more tender roots. Look for roots about 1 to 1.5 inches in diameter with fully colored red shoulders and white tips. Gently pull or loosen the soil with a small fork and lift the entire root from the ground. Radishes do not continue to improve in quality once mature; prolonged growth in warm weather or overmature roots become pithy and develop an unpleasant sharpness. Harvest regularly to encourage continued productivity if you've done successive plantings.
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“De 18 Jours is an old French variety whose very name reflects its purpose and reputation: 'of eighteen days.' For generations, European gardeners, particularly in France, have valued this radish for its unbelievably rapid yields. The variety became a favorite for forcing under glass during off-season months, allowing French gardeners to produce fresh radishes through winter when outdoor growing was impossible. This technique of indoor cultivation preserved and reinforced the variety's selection for speed and dependable performance, eventually bringing it to seed catalogs and home gardeners worldwide as a reliable heirloom.”