Summer Planting Guide (July–October): Lettuce, Tomatoes & Cucumbers

by Paramount Seeds on Jul 18 2026

Grow Your Best Summer Greenhouse Crops — July Through October

The July–October window demands the right varieties for heat tolerance, disease resistance, and consistent yield. Here are our picks across lettuce, tomato, and cucumber — plus key planting tips to keep your program on track. Not sure which varieties suit your specific setup? Our AI variety selection guide can help you model performance before you commit.

Lettuce

Lettuce Planting Tips

Target day temps of 72–78°F; use 30–40% shade cloth during peak July–August radiation.
Increase calcium and potassium in your EC program to reduce tip burn as temperatures peak.
Stagger transplant dates every 2–3 weeks for continuous harvest through October.

Muir Greenleaf Lettuce (Batavia) — Pelleted

A heat-tolerant Batavia greenleaf with crisp texture and uniform head weight. Reliable through summer and into the fall transition.

Type: Greenleaf (Batavia)
Seed form: Pelleted
Best for: Hydroponic channels, NFT, media-bed systems
Key trait: Heat tolerance, crisp texture, uniform weight

Rex F1 Butterhead Lettuce — Pelleted (Untreated)

Soft, pliable butterhead with strong tip-burn resistance. Untreated seed is compatible with organic and IPM programs. See our full butterhead variety guide for more options.

Type: Butterhead
Seed form: Pelleted, Untreated
Best for: Living lettuce, organic programs, clamshell retail
Key trait: Tip-burn resistance, soft texture, IPM-compatible

Tacitus F1 Romaine Lettuce — Pelleted

Upright romaine with excellent bolt resistance and a well-formed heart. Holds quality through late summer and early fall.

Type: Romaine
Seed form: Pelleted
Best for: Retail-ready heads, clamshell pack programs
Key trait: Bolt resistance, tight heart, shelf life
Season fit: Strong through late summer and early fall

Shop Butterhead → Shop Romaine → Shop Oakleaf →

Browse All Lettuce Varieties →

Tomatoes

Tomato Planting Tips

Target day temps of 75–82°F; monitor for ToBRFV pressure and scout weekly for mites and thrips.
Consider grafting onto a vigorous rootstock to improve plant health through the long summer cycle.
Begin adjusting EC and temperature set points in September as light levels drop heading into October.

Geronimo F1 Beefsteak Tomato

A proven industry benchmark. Exceptional fruit uniformity and generative balance through summer heat.

Type: Beefsteak
Best for: Long-season greenhouse programs, premium retail
Key trait: Fruit uniformity, generative balance, proven reliability
Season fit: Designed for high-pressure summer environments

Red Deuce F1 Beefsteak Tomato — Pelleted

High internal color, firmness, and brix consistency. A strong choice for premium retail and foodservice programs.

Type: Beefsteak
Seed form: Pelleted
Best for: Premium retail, foodservice supply
Key trait: Internal color, firmness, brix consistency
Season fit: Reliable July through October harvest windows

DRTH5075 F1 Beefsteak Tomato (ToBRFV)

Full ToBRFV resistance for high-pressure summer environments. Large, firm fruit with excellent shipping and shelf performance.

Type: Beefsteak
Resistance: ToBRFV (full)
Best for: Export programs, high-pressure virus environments
Key trait: ToBRFV resistance, fruit size consistency
Season fit: Critical for summer virus pressure peaks

Shop Beefsteak Tomatoes → Shop Truss Tomatoes →

Browse All Tomato Varieties →

Cucumbers

Cucumber Planting Tips

Target day temps of 75–82°F; maintain strong parthenocarpy conditions with consistent humidity management.
Scout weekly for spider mites and powdery mildew — both escalate rapidly in warm, dry summer conditions.
Consider grafting for improved vigor and soilborne disease tolerance in long summer production cycles.

Corinto F1 Slicer Cucumber (Treated)

Smooth, dark-green slicer with strong disease resistance and consistent fruit set through summer heat. For guidance on treated vs. untreated seed, see our seed treatment guide.