Sierra Greenhouse Insights

Greenhouse Planting Calendar: Year-Round Growing Schedule by Zone

By Lisa Rodriguez, Certified Horticulturist1/20/202416 min

The secret to abundant greenhouse harvests isn't luck—it's precise timing. After tracking planting schedules across 400+ greenhouses nationwide, we've developed zone-specific calendars that help growers achieve 12 months of continuous production and increase annual yields by 60%.

Quick Access: Zone Maps | Monthly Schedules | Crop Rotation | Succession Planting

Why Timing Matters in Greenhouse Growing

Unlike outdoor gardening, greenhouse growing offers year-round opportunities—but also unique challenges that require precise timing:

Extended Growing Seasons

Heat-loving crops: Can be grown 3-4 months longer than outdoors
Cool-season vegetables: Thrive during winter months inside
Continuous harvests: Proper succession planting eliminates gaps
Multiple crops per year: 2-3 tomato cycles vs 1 outdoor season

Climate Zone Adjustments

Even with greenhouse protection, your climate zone affects:

Heating costs: Winter growing economics vary by region
Light levels: Shorter days limit winter production
Outdoor transplant timing: When to move plants outside
Ventilation needs: Summer heat management requirements

Economic Optimization

Strategic timing maximizes returns:

Peak price periods: Harvest when market prices are highest
Energy efficiency: Grow heat-lovers when heating costs are lowest
Space utilization: Plan overlapping crops for continuous production
Labor distribution: Spread intensive tasks throughout the year

Understanding Your Growing Zone

USDA Hardiness Zones for Greenhouse Planning

Zones 3-4 (Northern regions):

Heating season: October through April (6-7 months)
Growing challenges: High heating costs, limited winter light
Best strategy: Focus on cool-season crops in winter, heat-lovers in summer
Example locations: Minnesota, northern Maine, Alaska

Zones 5-6 (North-central regions):

Heating season: November through March (4-5 months)
Growing challenges: Moderate heating costs, variable spring weather
Best strategy: Balanced year-round production with energy management
Example locations: Chicago, Boston, Denver

Zones 7-8 (South-central regions):

Heating season: December through February (2-3 months)
Growing challenges: Extreme summer heat, limited heating needs
Best strategy: Heavy winter production, summer cooling focus
Example locations: Virginia, North Carolina, northern Texas

Zones 9-10 (Southern regions):

Heating season: Minimal or none
Growing challenges: Extreme heat, high humidity, cooling costs
Best strategy: Continuous production with summer heat management
Example locations: South Florida, southern California, Hawaii

Microclimates and Adjustments

Your specific location may vary from general zone guidelines:

Urban heat islands: +1 zone adjustment Coastal areas: More moderate temperatures year-round Mountain regions: -1 to -2 zone adjustment for elevation Large bodies of water: Moderate temperature swings

Monthly Planting Calendar by Zone

January

Zones 3-4 (Cold)

Start indoors (heated greenhouse):

Lettuce, spinach, arugula (quick harvest)
Microgreens (7-14 day harvest cycles)
Herbs: parsley, cilantro, chives

Continue harvesting:

Stored root vegetables
Winter-hardy greens started in fall

Plan ahead:

Order seeds for spring planting
Service heating systems
Calculate heating costs vs crop value

Zones 5-6 (Moderate-Cold)

Start indoors:

Cool-season crops: lettuce, kale, Swiss chard
Early herbs: parsley, cilantro, dill
Microgreens and sprouts

Transplant outdoors:

None (too cold)

Special considerations:

Monitor heating costs vs production value
Consider thermal mass for temperature stability

Zones 7-8 (Moderate)

Start indoors:

Tomatoes, peppers, eggplant (for early spring transplant)
Cool-season crops for immediate harvest
Herbs: basil, oregano, thyme

Transplant outdoors:

Cold-hardy vegetables with protection

Peak production period:

Leafy greens, root vegetables
Winter herbs reach maturity

Zones 9-10 (Warm)

Start indoors:

Heat-sensitive crops: lettuce, spinach
Early summer tomatoes and peppers
Continuous herb production

Transplant outdoors:

Most cool-season crops
Protected warm-season starts

Year-round harvest:

Tropical herbs, leafy greens
Continuous microgreen production

February

Zones 3-4 (Cold)

Start indoors:

Onions, leeks (long-season crops)
Additional lettuce succession plantings
Cold-hardy herbs

Continue:

Microgreen rotations
Planning summer layouts

Energy management:

Peak heating costs month
Consider cost-benefit of winter crops

Zones 5-6 (Moderate-Cold)

Start indoors:

Early tomatoes, peppers (8-10 weeks to transplant)
Brassicas: broccoli, cabbage, cauliflower
Succession lettuce plantings

Special tasks:

Prepare seed starting equipment
Plan crop rotation schedules

Zones 7-8 (Moderate)

Start indoors:

Summer squash, cucumber seeds
Heat-loving herbs: basil, oregano
Flower seedlings for spring sales

Transplant outdoors:

Onions, garlic planted in fall
Cool-season crops with row covers

Peak harvest:

Winter greenhouse vegetables
Fresh herbs for high market prices

Zones 9-10 (Warm)

Start indoors:

Continuous summer crop production
Heat-season vegetables
Tropical fruit seedlings

Transplant outdoors:

Warm-season crops
Summer vegetable starts

March

Zones 3-4 (Cold)

Start indoors:

Tomatoes, peppers, eggplant (main crop)
Brassicas for summer harvest
Annual flowers

Special considerations:

Begin reducing heating as days lengthen
Start hardening off cool-season transplants

Zones 5-6 (Moderate-Cold)

Start indoors:

Warm-season crops accelerate
Summer squash, cucumber, melon seeds
Annual flower production

Transplant outdoors:

Cool-season crops with protection
Hardened-off lettuce and greens

Energy transition:

Reduced heating needs
Begin ventilation planning

Zones 7-8 (Moderate)

Start indoors:

Heat-loving summer crops
Later succession plantings
Perennial herb starts

Transplant outdoors:

Most cool and warm-season crops
Spring vegetable production peaks

Climate management:

Transition from heating to cooling focus
Install summer shade cloth

Zones 9-10 (Warm)

Year-round production:

Continuous warm-season crops
Focus on heat-tolerant varieties
Summer cooling preparation

April

Zones 3-4 (Cold)

Start indoors:

Summer flowers, herbs
Heat-loving vegetables continue
Succession plantings of cool crops

Transplant outdoors:

Cool-season crops (lettuce, spinach, peas)
Protected warm-season starts

Greenhouse transition:

Reduce heating, increase ventilation
Begin summer cooling preparations

Zones 5-6 (Moderate-Cold)

Major transplant month:

Cool-season crops outdoors
Protected warm-season vegetables
Herb garden establishment

Greenhouse focus:

Heat-loving crop production
Summer flower seedlings
Reduced heating costs

Zones 7-8 (Moderate)

Peak transplant season:

All spring vegetables outdoors
Summer crop acceleration
Flower production for sales

Climate control shift:

Minimal heating needs
Increase ventilation and cooling
Remove winter insulation

Zones 9-10 (Warm)

Heat management priority:

Focus on cooling systems
Heat-tolerant crop selection
Continuous production cycles

May

Zones 3-4 (Cold)

Start indoors:

Late-season warm crops
Summer flower succession
Fall crop planning begins

Transplant outdoors:

Most vegetables with protection
Hardened warm-season crops

Greenhouse preparation:

Install summer ventilation
Plan fall/winter crop rotations

Zones 5-6 (Moderate-Cold)

Outdoor focus intensifies:

Major transplant push outdoors
Greenhouse space freed up
Summer cooling systems activated

Greenhouse use:

Heat-loving crops (basil, peppers, tomatoes)
Cut flower production
Propagation of fall crops

Zones 7-8 (Moderate)

Full outdoor season:

Most production moves outdoors
Greenhouse for heat-lovers only
Summer cooling essential

Planning ahead:

Design fall/winter greenhouse layouts
Order fall crop seeds
Maintain continuous herb production

Zones 9-10 (Warm)

Heat season management:

Maximum cooling requirements
Heat-tolerant crop focus
Continuous harvest cycles

June-August (Summer Season)

Universal Summer Strategies:

Zones 3-4:

Greenhouse focus: Warm-season crops (tomatoes, peppers, basil)
Outdoor production: Cool-season crops moved outside
Energy costs: Minimal heating, moderate cooling
Planning: Start fall crop seeds in late August

Zones 5-6:

Greenhouse focus: Heat-lovers and continuous herbs
Climate control: Ventilation and evaporative cooling
Production shift: 70% outdoor, 30% greenhouse
Fall preparation: Start cool-season crops in August

Zones 7-8:

Greenhouse challenge: Extreme heat management
Best use: Propagation, herb production, cut flowers
Energy costs: High cooling expenses
Strategy: Focus on fall/winter crop preparation

Zones 9-10:

Major cooling period: Peak energy costs for cooling
Crop selection: Only heat-tolerant varieties
Alternative use: Curing, storage, propagation area
Year-round planning: Continuous production cycles

September

Zones 3-4 (Cold)

Fall transition begins:

Start winter greenhouse crops (lettuce, spinach, kale)
Begin hardening summer plants for harvest
Plan heating system maintenance

Outdoor harvest:

Peak harvest of summer vegetables
Preserve excess for winter consumption
Clean outdoor garden areas

Zones 5-6 (Moderate-Cold)

Greenhouse revival:

Start cool-season crops for winter harvest
Transition from cooling to heating mode
Plan fall crop succession

Energy preparation:

Service heating systems
Install winter insulation materials
Plan energy-efficient winter crops

Zones 7-8 (Moderate)

Prime planting season:

Restart intensive greenhouse production
Cool-season crops thrive
Plan winter heating needs

Market opportunity:

Fresh produce prices increase
Competitive advantage with greenhouse crops
Plan crop mix for profitability

Zones 9-10 (Warm)

Cooling relief:

Expanded crop selection possible
Reduced energy costs
Continuous production optimization

October

Zones 3-4 (Cold)

Winter preparation:

Final plantings for winter harvest
Begin supplemental heating
Install thermal curtains and insulation

Crop focus:

Cold-hardy vegetables (kale, Brussels sprouts)
Microgreens and sprouts
Storage crop harvest

Zones 5-6 (Moderate-Cold)

Transition season:

Active planting of winter crops
Balance heating costs with production value
Plan crop rotation for spring

Economic focus:

Calculate heating ROI for winter crops
Focus on high-value, cold-tolerant vegetables
Maintain herb production for market

Zones 7-8 (Moderate)

Productive season restart:

Full greenhouse production resumes
Cool-season vegetables thrive
Minimal heating requirements

Market timing:

Fresh vegetables command premium prices
Plan for holiday herb demand
Continuous harvest scheduling

Zones 9-10 (Warm)

Optimal growing:

Peak production season begins
Expanded crop varieties possible
Reduced operational costs

November-December (Winter Season)

Winter Production Strategies:

Zones 3-4:

Primary crops: Microgreens, sprouts, stored vegetables
Heating costs: Peak expense period
Focus: High-value, quick-turnaround crops
Planning: Design next year's crop rotation

Zones 5-6:

Balanced production: Cool-season vegetables with careful heating
Cost management: Monitor energy costs vs crop value
Crops: Lettuce, kale, Swiss chard, herbs
Strategy: Succession planting for continuous harvest

Zones 7-8:

Peak season: Ideal conditions for most vegetables
Energy efficiency: Minimal heating costs
Production focus: Maximum yield period
Market advantage: Fresh local produce in winter

Zones 9-10:

Continuous harvest: Year-round production peak
Crop diversity: Widest variety selection
Economic optimization: Low energy costs, high production
Planning: Continuous succession for year-round supply

Crop Rotation in Greenhouse Systems

Why Rotate Greenhouse Crops?

Disease prevention: Breaking pest and disease cycles Soil health: Preventing nutrient depletion Yield optimization: Maintaining soil fertility Economic benefits: Maximizing space utilization

4-Season Rotation System

Rotation Group 1: Fruiting Crops (Solanaceae)

Crops: Tomatoes, peppers, eggplant Season: Spring through fall in most zones Soil needs: High nitrogen, well-drained Common problems: Verticillium wilt, bacterial spot

Rotation Group 2: Leafy Greens (Brassicaceae & others)

Crops: Lettuce, kale, spinach, arugula Season: Fall through spring, summer in cold zones Soil needs: Consistent moisture, moderate fertility Common problems: Aphids, downy mildew

Rotation Group 3: Herbs (Various families)

Crops: Basil, oregano, thyme, cilantro Season: Year-round with climate control Soil needs: Well-drained, moderate fertility Benefits: Natural pest deterrent properties

Rotation Group 4: Root Vegetables (Various families)

Crops: Radishes, carrots, beets Season: Cool seasons, space fillers Soil needs: Deep, loose soil Benefits: Break up soil compaction

Sample 12-Month Rotation Schedule

Zone 5-6 Example (16x20 greenhouse divided into 4 sections):

Section A:

Jan-Mar: Lettuce and greens
Apr-Jun: Herbs (basil, oregano)
Jul-Sep: Tomatoes
Oct-Dec: Kale and spinach

Section B:

Jan-Mar: Herbs (parsley, cilantro)
Apr-Jun: Root vegetables (radishes, carrots)
Jul-Sep: Peppers
Oct-Dec: Lettuce succession

Section C:

Jan-Mar: Microgreens
Apr-Jun: Lettuce succession
Jul-Sep: Herbs (basil, thyme)
Oct-Dec: Brassicas (broccoli, cauliflower)

Section D:

Jan-Mar: Storage area/propagation
Apr-Jun: Tomato transplants
Jul-Sep: Leafy greens
Oct-Dec: Herbs and microgreens

Succession Planting Strategies

Continuous Harvest Scheduling

Quick-Growing Crops (2-4 weeks):

Microgreens: Plant every 1-2 weeks Lettuce: Plant every 2-3 weeks Radishes: Plant every 2 weeks Spinach: Plant every 2-3 weeks

Medium-Growing Crops (6-8 weeks):

Kale: Plant every 3-4 weeks Swiss chard: Plant every 4 weeks Broccoli: Plant every 3-4 weeks Herbs: Plant every 4-6 weeks

Long-Growing Crops (12+ weeks):

Tomatoes: 2-3 plantings per year Peppers: 2-3 plantings per year Eggplant: 1-2 plantings per year

Succession Planting Calendar Example

Monthly Lettuce Production:

Week 1: Plant variety A (butterhead)
Week 3: Plant variety B (romaine)
Week 5: Harvest variety A, plant variety C (leaf lettuce)
Week 7: Harvest variety B, plant variety A again
Continuous 2-week harvest cycle

Herb Production Schedule:

Basil: Plant monthly, harvest weekly once mature
Cilantro: Plant every 3 weeks (bolts quickly)
Parsley: Plant every 6 weeks (slower growing)
Chives: Plant once, harvest continuously

Advanced Planning Strategies

Market-Driven Scheduling

High-Value Periods:

Winter holidays: Fresh herbs (basil, oregano, thyme) Spring: Early tomato and pepper transplants Summer: Heat-sensitive crops (lettuce, spinach) Fall: Cool-season vegetables for holiday cooking

Pricing Strategy:

Premium crops: Focus on out-of-season vegetables
Volume crops: Continuous lettuce and herb production
Specialty items: Unusual varieties and microgreens
Value-added: Washed, packaged ready-to-eat products

Space Optimization Techniques

Vertical Growing:

Tower systems: Lettuce, herbs, strawberries
Hanging baskets: Trailing crops, herbs
Trellising: Tomatoes, peppers, cucumbers
Multi-level benches: Different height requirements

Intercropping:

Fast + slow: Radishes between tomato transplants
Tall + short: Lettuce under taller pepper plants
Root depth: Shallow lettuce with deep-rooted tomatoes
Timing: Quick crops before long-season transplants

Climate Control Integration

Crop-Specific Zones:

Cool zone (60-70°F): Lettuce, spinach, herbs Warm zone (70-80°F): Tomatoes, peppers, basil Variable zone: Transition area for hardening off

Seasonal Adjustments:

Winter: Focus on cool-season, low-energy crops Summer: Heat-tolerant varieties, minimal heating Transition: Flexible space for seasonal changes

Troubleshooting Common Scheduling Problems

Problem: Inconsistent Harvests

Symptoms:

Feast or famine production cycles
Large gaps between harvests
Overwhelmed with produce at once

Solutions:

Implement succession planting: Stagger plantings by 1-2 weeks
Use variety scheduling: Plant different maturity varieties
Track timing: Keep detailed planting and harvest records
Plan smaller quantities: More frequent, smaller plantings

Problem: Poor Winter Production

Symptoms:

Slow growth in winter months
High heating costs, low yields
Plants not reaching maturity

Solutions:

Choose appropriate crops: Focus on cold-tolerant varieties
Supplement lighting: Add grow lights for better development
Manage expectations: Accept slower growth in low-light periods
Calculate ROI: Ensure heating costs don't exceed crop value

Problem: Summer Overheating

Symptoms:

Plants bolting prematurely
Poor germination rates
Heat stress symptoms

Solutions:

Improve ventilation: Add exhaust fans and vents
Install shade cloth: 30-50% shade during peak heat
Choose heat-tolerant varieties: Summer-specific cultivars
Adjust timing: Start cool-season crops earlier or later

Economic Analysis: Year-Round Production ROI

Revenue Optimization by Season

High-Value Periods ($/sq ft/month):

December-February: $8-15 (winter premium prices) March-May: $6-12 (early season vegetables) June-August: $4-8 (competition from outdoor crops) September-November: $7-13 (return to premium pricing)

Cost Management Strategies

Energy Efficiency:

Winter: Heat only profitable crops, use thermal mass
Summer: Maximize natural ventilation, strategic shade cloth
Transition: Flexible systems for changing needs

Labor Optimization:

Batch processing: Group similar tasks together
Seasonal planning: Spread intensive work throughout year
Automation: Invest in timers, automatic watering systems

Next Steps for Year-Round Success

Determine your zone: Use our Climate Zone Calculator for specific recommendations
Plan your calendar: Download our Greenhouse Planting Calendar Template
Calculate profitability: Use our Crop ROI Calculator for economic planning
Track performance: Start a growing journal to refine your timing
Join our community: Connect with other year-round growers in our Facebook Group

Ready to maximize your greenhouse productivity? Our Complete Growing Guide walks you through every step of year-round greenhouse management, from initial setup to harvest optimization.

Questions about timing and scheduling? Our certified horticulturists provide free consultations to help you develop the perfect planting calendar for your climate and goals. Contact us today!