What To Grow In A Kansas Greenhouse For Every Season

The Kansas climate is continental, with cold winters, hot summers, and rapid transitions in spring and fall. A greenhouse converts that variability into a controlled environment, extending seasons and enabling year-round production. This article provides practical, detailed guidance on what to grow in a Kansas greenhouse in each season, how to manage environmental controls, and concrete planting, pest, and fertility strategies to maximize yields and reduce headaches.

Kansas climate basics for greenhouse growers

Kansas spans USDA zones roughly 5b through 7a depending on location. Winters can drop well below freezing; summer days often exceed 90 F with low relative humidity. Those external extremes mean a greenhouse must manage heating, cooling, ventilation, and humidity to grow predictably.
Greenhouse operators in Kansas should plan for:

• cold snaps below 0 F in the west and northwest;
• late spring frosts in many areas;
• intense solar radiation and heat in midsummer; and
• dry winter air that increases plant transpiration stress when heated.

Understanding these tendencies shapes crop choices and the timing for sowing, transplanting, and harvesting.

Year-round greenhouse planning principles

Successful year-round production follows a few constants:

• control temperature by crop needs (day/night targets);
• manage humidity to minimize disease yet keep plants comfortable;
• provide adequate light (supplemental in winter, shading in summer);
• schedule succession plantings to avoid gaps;
• match water and nutrient delivery to crop growth stage.

Plan beds, benches, and containers so you can rotate crops and replace plants quickly. Leave space for potting, seed starting, and quarantine of new stock.

Spring: start early, focus on seedlings and cool-season crops

Spring is the best time to launch major greenhouse production. Use the greenhouse to start seedlings early for outdoor transplanting and to produce tender vegetables and flowers for an early market.
Recommended spring crops and uses:

• cool-season greens: lettuce, spinach, arugula, mustard greens, and baby leaf mixes. Aim for 55-70 F daytime and 45-55 F nights for most varieties.
• brassicas: broccoli, cauliflower, cabbage, kale, collards. Start seeds 6-8 weeks before outdoor transplant.
• peas: shelling and snap peas for early harvest; use trellises in the greenhouse for earlier production.
• early tomatoes and peppers: start transplants 6-8 weeks before final outdoor transplant in late spring.
• herbs: parsley, cilantro, chives, dill for early fresh harvest.
• bedding plants and flowers: pansies, violas, snapdragons, and primulas for early color.

Spring management tips:

• seed trays: maintain substrate temperatures 65-75 F for rapid germination of most vegetables.
• hardening: move seedlings to cooler nights and higher light a week before transplant.
• ventilation: open vents and use circulation fans to reduce damping-off and fungal problems as outdoor temperatures rise.

Summer: keep things cool and grow heat-loving crops

Summer in Kansas puts the greenhouse under heat stress. With proper cooling and shading, you can grow both heat-tolerant vegetables and off-season greens in shaded areas.
Good summer greenhouse crops:

• cucurbits: greenhouse cucumbers (parthenocarpic varieties), small melons, and small vining squash with trellising and strong ventilation.
• tomatoes and peppers: choose heat-tolerant varieties. Use shade cloth and good air flow to prevent blossom drop and sunscald.
• eggplant: tolerates heat well and does fine in high-temp greenhouses when pollinated.
• basil and other culinary herbs: thrive in warm temperatures with regular harvests; watch for downy mildew on basil in humid conditions.
• heat-tolerant greens: Newer bolt-resistant lettuces, Malabar spinach, and Swiss chard in partial shade.

Summer management specifics:

• shading: 30-50 percent shade cloth for peak heat days; consider retractable shade for flexibility.
• evaporative cooling: if available, use wet walls or misting to reduce greenhouse air temperatures by 10-20 F when outside humidity is low.
• air flow: run horizontal airflow fans and ridge vents to prevent heat pockets and encourage pollinator movement if you need fruit set.
• irrigation: increase frequency but avoid waterlogged media. Drip irrigation with pressure-compensating emitters works well.

Fall: extend the harvest and transition to cool season

Fall is the second spring for many greenhouse operations. Temperatures moderate and pests slow down, allowing productive plantings of cool-season crops and a second flush of summer crops that tolerate cooler nights.
Fall crop options:

• repeat plantings of lettuce, spinach, and salad mixes for autumn harvests.
• overwintering brassicas: grow broccoli and kale late into fall for continuous harvests.
• root crops in deep containers: beets and radishes can be produced in cooler greenhouse conditions.
• second crops of tomatoes: in shaded parts or with supplemental heat, tomatoes can produce into fall.
• flowers and cut greens: chrysanthemums and late-season cut flowers for fall markets.

Fall management:

• monitor for aphids and whiteflies as indoor populations can spike when outside temperatures fall and pests seek shelter.
• begin testing heating systems and sealing drafts before hard freezes.
• use row covers or thermal blankets in the greenhouse for extra frost protection if needed.

Winter: focus on leafy crops, microgreens, and overwintering plants

Winter is where a Kansas greenhouse earns its keep. With heating and supplemental lighting, you can produce high-value crops that fetch a premium when outdoor options are scarce.
Top winter greenhouse crops:

• microgreens: very profitable, fast turnover (7-21 days), and low space needs. Varieties: arugula, radish, peas, sunflower, and mixed microgreen blends.
• salad greens and baby leaf mixes: grow under LED lighting with day/night temps 60-68 F to slow bolting and improve quality.
• herbs: thyme, oregano, rosemary, and mint can be grown through winter with adequate light.
• cut flowers: forcing bulbs and perennial cuttings indoors gives winter blooms.
• overwintering perennials and tender plants: potted herbs and ornamental shrubs can be maintained with frost-free zones.

Winter environment control:

• heating: aim for 55-65 F day temps for low-energy systems focused on greens; 65-75 F for herbs and flowering crops.
• lighting: supplemental LED grow lights for 10-14 hours per day depending on crop. Aim for 100-200 umol/m2/s for leafy greens; 300-400 umol/m2/s for flowering/fruiting crops.
• humidity: keep relative humidity moderate (50-70 percent) to prevent fungal disease while minimizing water stress.
• air exchange: some fresh air daily prevents buildup of CO2 imbalances and stale air; consider CO2 enrichment only if you can maintain a sealed environment and stable light levels.

Varieties and cultivar selection: pick for environment, not just flavor

Choose cultivars that match greenhouse conditions:

• tomatoes: indeterminate greenhouse or “beefsteak” types for trellised systems; parthenocarpic varieties for greenhouses without pollinators.
• cucumbers: greenhouse-specific parthenocarpic English cucumbers resist bitterness and set fruit without bees.
• lettuce: bolt-resistant and slow-bolting varieties for warm transitions.
• peppers: select early-maturing varieties for autumn; choose heat-tolerant types for summer.
• herbs: compact, slow-growing cultivars are easier to manage on benches.

Ask seed suppliers for greenhouse-specific selections when possible. Trial small batches to identify what performs in your exact microclimate.

Pest and disease management in Kansas greenhouses

Greenhouse pests can be worse than outdoor pests because of the stable environment. Common issues in Kansas greenhouses include aphids, whiteflies, spider mites, thrips, fungus gnats, and powdery mildew.
Integrated pest management steps:

• sanitation: remove plant debris, disinfect benches and tools, and avoid bringing in outside soil.
• monitoring: use yellow sticky traps, inspect foliage weekly, and maintain a pest log.
• biological controls: introduce beneficial insects (Aphidoletes, Encarsia, predatory mites) early for preventive control.
• cultural controls: adjust humidity and temperature, avoid over-fertilization that promotes soft growth attractive to pests.
• chemical controls: use selective materials only as a last resort and rotate modes of action to limit resistance.

Prevent disease by keeping leaf wetness low, spacing plants for air flow, and using disease-free starting material.

Soil, containers, and fertility recommendations

Healthy media and precise fertility lead to reliable production.
Media and containers:

• use a sterile soilless mix for seed starting to reduce pathogens.
• for bench production, mixes with peat/perlite/composted bark give good drainage and water retention.
• for larger containers, choose mixes with adequate cation exchange capacity and added slow-release starter nutrients.

Fertility:

• vegetative growth: higher nitrogen balance (e.g., 3-1-2 NPK), but avoid excess that invites pests and weak stems.
• fruiting stage: increase potassium for fruit set and quality.
• pH: maintain 5.8-6.5 for most vegetables; adjust for specific crops like blueberries which need lower pH.
• hydroponics: maintain EC/ppm appropriate for crop stage (e.g., 1.2-1.8 mS/cm for lettuce, 2.0-3.0+ for fruiting crops) and monitor pH daily.

Regular tissue testing and EC monitoring will prevent nutrient disorders common in greenhouse production.

Succession planting and scheduling

To maximize year-round output, practice succession planting:

• stagger seedings every 2-3 weeks for greens and herbs.
• map out a year-long calendar with graft points at seasonal transitions.
• maintain a seedling rotation area to replace quick-turnover crops.

A simple schedule example:
1. January: start microgreens, herb cuttings, and early lettuce under lights.
2. February-March: begin tomato/pepper seedlings for outdoor transplant and greenhouse summer crops.
3. May-July: plant heat-tolerant cucumbers and peppers for summer harvest.
4. August-September: plant autumn lettuce and brassicas for fall and winter harvest.
5. October-December: intensify microgreens and herbs for winter market.
Adjust timing according to your local freeze dates and market windows.

Practical takeaways

• Use the greenhouse to start seedlings, extend seasons, and produce high-value winter crops like microgreens and herbs.
• Match crops to season: cool-season greens in spring/fall/winter, heat lovers in summer with shading and ventilation.
• Invest in basic climate controls: ventilation, shade cloth, and a reliable heat source will cover 80 percent of temperature problems.
• Monitor pests proactively; biological controls are more effective and sustainable than reactive chemical treatments.
• Keep detailed schedules and trial small quantities of new cultivars before scaling.

A Kansas greenhouse is an incredibly versatile tool. With careful planning and attention to environmental management, you can produce fresh vegetables, herbs, flowers, and specialty crops throughout the year and capture market windows where outdoor production cannot compete.