What To Grow In A Georgia Greenhouse Each Season

Greenhouses in Georgia offer the best of both worlds: protection from extreme weather and a controlled environment that extends the growing season. With a climate that ranges from warm coastal lowlands to cooler mountain zones, greenhouse gardeners can produce fresh vegetables, herbs, flowers, and tender fruits nearly year-round if they plan by season. This guide covers what to grow each season in a Georgia greenhouse, how to manage the environment, and practical schedules and tips to maximize yield and quality.

Understanding Georgia’s Growing Window

Georgia’s USDA hardiness zones range from about 6b in the mountains to 9a along the coast. That variation affects frost dates, but for greenhouse planning use these general markers:

• Last expected frost for much of central Georgia: mid-March to early April.
• First expected frost for much of central Georgia: mid-November to early December.

Greenhouses shift those dates considerably by protecting crops from frosts and allowing earlier starts in spring and later harvests into winter. However, greenhouse management must address solar heat in summer and freeze risk in winter. Plan crops and systems with those dual extremes in mind.

Key Environmental Controls for Year-Round Production

Good greenhouse gardening is mostly about managing temperature, light, humidity, irrigation, and pests. Below are the concrete targets and methods you should use in Georgia.

Temperature targets (day/night)

• Leafy greens: 50-75 F day, 45-60 F night.
• Fruiting crops (tomato, pepper, cucumber): 70-85 F day, 55-70 F night.
• Herbs: 60-80 F daytime, 50-65 F night.
• Seedling propagation: 70-80 F daytime, slightly cooler nights.

Light and shading

In late spring and summer, solar radiation inside a greenhouse can push temperatures dramatically high. Use 30-60 percent shade cloth depending on crop and orientation. Leafy greens tolerate heavier shading; fruiting crops need more light but still benefit from partial shading during mid-day heat spikes.

Ventilation and cooling

• Use automated ridge and side vents or exhaust fans for continuous airflow. Cross-ventilation is critical.
• In hot, humid Georgia summers consider evaporative cooling pads with fans for larger structures.
• Circulation fans reduce microclimates and discourage fungal disease.

Heating and freeze protection

• Small electric or propane heaters with thermostats work for occasional cold snaps.
• For critical tender crops, use thermal mass (barrels of water) or double-layer polyethylene and row covers to trap heat overnight.
• Minimum safe greenhouse temperature for most winter crops is 40-45 F; some hardy greens tolerate lower.

Water and fertility

• Maintain substrate pH around 5.8-6.5 for most vegetables in pots or beds.
• Use drip irrigation or micro-sprinklers for consistent moisture; avoid overhead watering on foliage in cool seasons.
• Fertility: use balanced fertilizers early; shift to higher potassium during fruit set. Monitor electrical conductivity (EC) if using hydroponics.

What To Grow in Winter (December – February)

A Georgia greenhouse can be very productive over winter if you choose cool-season crops and protect them from prolonged cold. Focus on high-value greens, brassicas, and herbs.

Recommended crops

• Leafy greens: lettuce, spinach, arugula, mache, Swiss chard.
• Brassicas: broccoli, cauliflower, cabbage, kale.
• Root crops: carrots, beets, radishes.
• Herbs: parsley, cilantro, chives.
• Overwintered perennials: container citrus, rosemary, thyme (if you can maintain 50+ F).

Practical winter tips

• Start transplants in late summer or early fall for fall-to-winter harvests; many brassicas require cool development for best texture.
• Maintain daytime temperatures in the 50-65 F range for greens and up to 70 F for brassicas on sunny days.
• Use low tunnel row covers inside the greenhouse for additional protection during cold snaps.
• Keep humidity moderate to minimize botrytis and powdery mildew; increase ventilation on sunny days.

What To Grow in Spring (March – May)

Spring is prime time to exploit the greenhouse advantage for early warm-season crop production. You can get tomatoes, cucurbits, and peppers into productive stages before the field season.

Recommended crops

• Tomatoes: start seeds 6-8 weeks before expected transplant.
• Peppers: start 8-10 weeks before transplant.
• Eggplant: start 7-8 weeks before transplant.
• Cucumbers and squash: start 3-4 weeks before transplant or direct-seed into containers.
• Early greens and herbs: continuous sowings for harvest.

Propagation schedule examples (central Georgia)

1. Start tomatoes indoors: late January to mid-February for March transplants into greenhouse benches.
2. Start peppers: early to mid-February.
3. Start cucumbers: early March for mid-April planting to catch warm days.

Practical note: Harden seedlings by exposing them to cooler nights and more airflow for 7-10 days before moving to full greenhouse benches or beds to reduce transplant shock.

What To Grow in Summer (June – August)

Summer is the most challenging season for greenhouse growers in Georgia due to heat and humidity. Choose heat-tolerant crops, use cooling, and prioritize water management.

Recommended crops and strategies

• Heat-tolerant tomatoes and cherries: select varieties known to set fruit at higher temperatures.
• Peppers and eggplant: many pepper types can handle high heat if root zone is cool and soil moisture consistent.
• Okra: thrives in heat and can be grown in containers or beds for cut-and-come-again harvests.
• Basil and other heat-loving herbs: basil responds well to warm conditions and high light.
• Cut flowers and ornamentals: zinnias and sunflowers during well-ventilated conditions.

Heat management specifics

• Use 40-60 percent shade cloth during peak summer months for delicate crops.
• Employ evaporative cooling if your greenhouse has sufficient airflow and water supply.
• Install automatic venting and temperature alarms; target maximum daytime temp under 95 F to avoid blossom drop and stress.
• Mulch containers and maintain consistent drip irrigation to keep roots cool.

What To Grow in Fall (September – November)

Fall is an excellent time for greenhouse production because daytime temperatures moderate and pests may decline. Focus on greens, brassicas, and a second tomato or pepper crop if space and heat allow.

Recommended crops

• Leafy greens for high-value harvests: plant succession crops every 2-3 weeks.
• Brassicas: transplant broccoli and cabbage started in late summer.
• Fall beans and peas: choose faster-maturing varieties to beat first frost.
• Cucumbers and squash: plant early in fall to harvest before heavy frosts.

Succession planting plan

• Sow quick-maturing greens every 10-14 days from late August through October to maintain continuous supply.
• Transplant brassicas in August-September to harvest through the fall.

Year-Round Crops and Uses

• Microgreens and baby greens: fast turnover (7-21 days) and excellent year-round greenhouse crop.
• Herbs: basil, mint, parsley, and cilantro can be produced continuously with scheduled cuttings.
• Container citrus and subtropical ornamentals: bring tender plants into the greenhouse for winter protection.
• Seed starting and propagation: the greenhouse is ideal for producing your own transplants for outdoor beds and for staggered harvests.

Pest and Disease Management in a Georgia Greenhouse

Georgia humidity encourages several greenhouse pests and diseases. Integrated Pest Management (IPM) is essential.

• Monitor weekly with yellow sticky traps for whiteflies and thrips.
• Scout for aphids on new growth, and spider mites on undersides of leaves during hot dry spells.
• Avoid overhead watering when possible to reduce foliar diseases; use soil drench or drip.
• Use biological controls: beneficial nematodes, predatory mites, and parasitic wasps for whiteflies and aphids.
• Maintain sanitation: remove plant debris and disinfect tools between crops.

Soil, Containers, and Hydroponics

• Use high-quality soilless mixes for container production and propagation; mix should drain well but retain moisture.
• Raised beds with amended soil work well for larger crops if drainage and soil temperature are managed.
• Hydroponic and ebb-and-flow systems are efficient for year-round production in controlled greenhouses; monitor EC and pH daily.

Concrete Takeaways and a Seasonal Checklist

• Winter: focus on cold-tolerant greens and brassicas; maintain daytime temps 50-70 F.
• Spring: start tomatoes, peppers, and cucurbits early; harden transplants before moving.
• Summer: prioritize heat-tolerant crops, aggressive shading, and evaporative cooling; keep root zones cool and moisture steady.
• Fall: succession plant greens and brassicas; use the cooler weather to finish second crops.
• Always: maintain ventilation, monitor humidity, use drip irrigation, rotate crops, and employ IPM practices.

Quick Starter List for a Georgia Greenhouse

• Leafy greens: lettuce, spinach, Swiss chard, arugula.
• Brassicas: broccoli, kale, cabbage, cauliflower.
• Fruiting vegetables: tomatoes (heat-tolerant types), peppers, cucumbers.
• Heat lovers: okra, basil, eggplant.
• Fast-turn crops: microgreens, radishes, baby salads.
• Perennials/tender: container citrus, rosemary, thyme.

Final Advice

Plan your greenhouse crops around temperature extremes and light. Use the greenhouse to start transplants early, produce high-value winter and spring crops, and protect tender plants in colder months. With attention to ventilation, shading, irrigation, and disease prevention, a Georgia greenhouse can provide fresh produce almost year-round and dramatically improve crop quality and consistency.