Rex F1 Butterhead Lettuce — The Industry Standard for Greenhouse & Hydroponic Production

When growers talk about a butterhead lettuce that simply performs, Rex F1 is almost always the first name mentioned. Developed by Rijk Zwaan, Rex has earned its place as one of the most widely grown butterhead varieties in professional greenhouse and hydroponic operations worldwide — and for good reason.

Why Growers Choose Rex

Rex is classified as a thick-leaved summer type, but its adaptability makes it a reliable year-round performer. Here's what sets it apart:

• Exceptional head quality — uniform, well-closed base with leaves that are not brittle, making harvest and packing clean and efficient.
• Slow-bolting — extended harvest windows without the risk of premature bolting under warm conditions.
• Outstanding tipburn resistance — one of Rex's most valued traits in controlled-environment production. Learn more about managing this challenge in our guide: Controlling Tipburn in Hydroponic Lettuce.
• Strong disease resistance — resistant to Bremia lactucae (Downy Mildew) races BL 1–12, 17, 18, and 22, covering the most commercially significant races in North American and European production.

Ideal Growing Environments

Rex thrives in:

• Greenhouse production (NFT, DWC, and media-bed systems)
• Hydroponic vertical farms
• High-tunnel and protected-environment culture

Its compact, well-formed heads and clean base make it particularly well-suited for clamshell and living lettuce retail formats.

Pelleted, Untreated Seed

Rex is available from Paramount Seeds as pelleted, untreated seed — the preferred format for precision seeding into plug trays and automated transplant lines. Pellets ensure consistent singulation and uniform germination spacing without the need for chemical seed treatments, keeping your program clean and certification-friendly.

Looking for a treated alternative or a different head type? Consider Frank F1 or Charles F1 as complementary options in your butterhead rotation.

Available Pack Sizes

Rex F1 pelleted seed is available in sizes scaled to every operation — from trial plantings to full commercial programs:

• 100 seeds — $4.40
• 250 seeds — $10.00
• 1,000 seeds — $30.90
• 5,000 seeds — $149.00
• 25,000 seeds — $720.00
• 50,000 seeds — $1,440.00
• 100,000 seeds — $2,805.00

Related Resources

• Controlling Tipburn in Hydroponic Lettuce