What To Grow In A Kansas Greenhouse For Quick Harvests

Growing in a greenhouse in Kansas gives you a powerful advantage over open-field gardening: the ability to control temperature, humidity, and season length. If your priority is speed to harvest — whether for market, CSA, restaurant supply, or home use — choose crops and systems that maximize turnover, minimize space and inputs, and tolerate the local climate’s swings. This guide focuses on crops and practical practices that deliver fast, reliable harvests in Kansas greenhouses, with specific recommendations, environmental targets, and scheduling tactics you can use right away.

Kansas climate considerations for greenhouse growers

Kansas spans USDA zones roughly from 5a/5b in the west to 6a/7a in the east. Winters can be cold, springs can bring late frosts and hail, summers are hot and dry in the west and more humid in the east, and wind is a major factor statewide. Your greenhouse strategy should reflect:

• whether you will heat year-round (true year-round production) or use an unheated/solar greenhouse for season extension only;
• your location in Kansas and how last-frost and first-frost dates vary (late March to mid-May for last frost depending on location; first frost often mid-September through October);
• wind exposure and need for windbreaks or reinforced glazing.

Choosing quick-harvest crops compensates for short outdoor seasons and lets you get multiple successions per year even in an unheated house.

Quick-harvest crop categories that perform well in Kansas greenhouses

Microgreens and shoots (7-21 days)

Microgreens and shoot systems are the fastest-return greenhouse crops you can grow. They require minimal space, simple substrate, and harvest in 7-21 days depending on species.

• Recommended species: radish, broccoli, mustard, sunflower, pea shoots, arugula.
• Growing targets: germination 65-75degF; bright diffuse light after cotyledons expand; harvest at first true leaves (typically 7-14 days for radish, 10-20 days for peas and sunflower).
• Systems: shallow flats with a sterile seed-start mix, high seed density, overhead misting or fine spray for irrigation.
• Practical tip: plan succession trays every 3-4 days for continuous weekly harvests.

Baby salad greens and cut-and-come-again lettuces (18-40 days)

Baby leaf mixes and “cut-and-come-again” lettuce varieties give high yield fast with minimal deep root space.

• Recommended species/varieties: looseleaf lettuce (baby-leaf types), arugula, mizuna, tatsoi, baby spinach, baby chard, mustard greens.
• Days to harvest: baby leaves in 18-30 days; continuous harvest if cutting 1 inch above soil and allowing regrowth.
• Temperature: 50-70degF for best flavor and to delay bolting; cooler nights (down to low 40s) help lettuce crispness if your greenhouse permits.
• Spacing and sowing: sow densely (4-6 oz per 10 sq ft for commercial baby leaf); stagger plantings every 7-14 days.

Fast root crops for baby harvests (20-45 days)

Root crops are often slower to reach full size, but baby roots and greens can be harvested quickly for premium value.

• Radishes: 20-30 days to baby size (very reliable and fast).
• Baby carrots: 30-50 days depending on variety; sow shallow and harvest selectively.
• Beets for baby roots and greens: 30-45 days; beet greens are edible earlier.
• Practical tip: use market labels like “baby carrots” or “early” varieties and sow thinly in raised beds or deep flats for straight, small roots.

Herbs: high-value, quick-cut options (20-60 days)

Herbs are compact, repeatedly harvestable, and command good prices. Some establish and produce quickly.

• Fast herbs: basil (20-30 days for baby leaf; continual harvest at 3-4 weeks), cilantro (40-60 days to full but leaves usable earlier), chives (sow once and cut repeatedly), parsley (establishes more slowly but harvestable), dill (30-60 days).
• Environmental notes: basil thrives in warm, humid conditions (70-80degF daytime); cilantro prefers cooler (50-65degF) and bolts in heat.
• Harvest strategy: frequent light cuts encourage bushier regrowth; staggered sowings maintain supply.

Fast vining/fruiting crops for quick yield (40-70+ days)

Certain determinate and dwarf varieties of cucumbers and cherry tomatoes will begin producing quickly in a warm greenhouse. They require more space and support but can be high-yielding.

• Cucumbers: pickling and small slicing types can begin producing in about 40-60 days from direct sow or earlier from transplants.
• Cherry tomatoes: indeterminate cherries often start fruiting 55-70 days after transplant; provide pollination (hand pollinate or provide bumble bees) and trellising.
• Peppers generally take longer (60-90 days) and are not ideal if you need extremely fast returns.
• Practical note: choose short-vine or parthenocarpic cucumbers for greenhouse fruiting without insects.

Quick legumes and brassicas (30-60 days)

• Peas (for shoots or young pods) can produce harvests in 30-50 days for early pod picks and much earlier if grown for pea shoots.
• Baby broccoli and broccolini-type hybrids can be harvested as small heads in 45-60 days for specialty markets.

Greenhouse environment and cultural practices that speed harvests

Temperature and light targets

• Germination: aim 65-80degF for most seeds (herbs like basil prefer the high end).
• Vegetative growth: 60-75degF daytime; 50-60degF nighttime for cool-season greens; 70-80degF daytime for fast herbs and cucumbers.
• Light: 10,000-20,000 lux (full sunlight) is ideal; supplement with 12-16 hours of LED lighting in winter or on cloudy Kansas days.
• Shade in summer: use 30-50% shade cloth or evaporative cooling to prevent bolting and heat stress during hot Kansas summers.

Water, fertility, and substrate

• Substrate: fast-growing crops like microgreens and baby leaf do best in sterile, well-draining seed mixes with good water holding capacity.
• Irrigation: frequent light waterings or ebb-and-flow for flats; drip irrigation for beds and hanging baskets. Avoid overwatering to minimize disease.
• Fertility: baby greens and microgreens need light fertility; use diluted liquid feed (50-100 ppm N) or tailored hydroponic nutrient solutions for soilless systems. Switch to balanced 14-14-14 slow-release for longer-season crops if using soil.

Pest and disease management

• Sanitation: sterilize trays, rotate crops, remove crop residue after harvest, and disinfect tools to prevent damping-off and botrytis.
• Ventilation: maintain good air exchange to reduce humidity-driven diseases; use horizontal airflow fans and exhaust vents.
• Integrated pest control: monitor weekly, use sticky traps, introduce beneficials (predatory mites, parasitic wasps) for whitefly and aphid control, and use soap/pyrethrin sprays only when needed.

Scheduling and succession planting for continuous quick harvests

To maximize throughput, plan multiple successions and overlapping harvest windows. Example tactics:

• Microgreens: sow a new tray every 3-4 days for continuous weekly harvests.
• Baby leaf greens: sow small beds or flats every 10-14 days; rotate four-week cycles to keep beds in production.
• Herbs: start new basil every 3-4 weeks to maintain a steady supply as mature plants are cut back.
• Root baby crops: stagger sowings every 2-3 weeks to supply baby roots without large storage requirements.
• Plant heat-sensitive crops (lettuce, spinach) on the greenhouse north side and warm-loving crops (basil, cucumber) on the south/warm side during shoulder seasons.

Practical scheduling example for a central-Kansas heated greenhouse (approximate timing):

• December-February: Microgreens, herbs under supplemental LEDs, early start transplants for spring.
• March-April: Intensify baby leaf and root baby production; begin peas and early cucumber transplants later in April.
• May-August: Use shade cloth; continue continuous baby leaves in cooler bench areas; move cucumbers and tomatoes to production frame with adequate ventilation.
• September-November: Shift back to cool-season greens, radishes, and fast herbs as temperatures cool; prepare greenhouse for short-season winter cycles or full heating if desired.

Crop-specific quick tactics and cultivar selection

• Microgreens: use highest-germination seed, sow thickly (approx. 10-12 g per 10×20 tray for radish), moderate fertility after first true leaves if growing beyond cotyledon stage.
• Lettuce/baby leaf: choose “cut-and-come-again” varieties; aim for harvest at 3-4 inches for best regrowth and flavor; maintain cooler temps to prevent bitterness.
• Radishes: use early varieties labeled for baby harvest; shallow sowing and frequent, steady moisture prevents pithy roots.
• Basil: pinch early to encourage branching; keep stems trimmed to 3-4 nodes; harvest before flowering for best flavor.
• Cucumbers/tomatoes: keep plants trained vertically, remove lower leaves to improve airflow, and plan for pollination (tomatoes self-pollinate but benefit from vibration; cucumbers may need bees or hand pollination for some varieties).

Quick-start checklist for fast greenhouse harvests in Kansas

• Decide: heated year-round vs season-extension unheated greenhouse.
• Prioritize crops: microgreens, baby leaf greens, radishes, fast herbs, early cucumbers/tomatoes.
• Environment: maintain targeted temps (see earlier), provide supplemental LED lighting in winter, and use shade cloth in summer.
• Irrigation and fertility: install drip or ebb-and-flow, use diluted liquid feed for fast crops.
• Pest/disease prevention: practice sanitation, rotate crops, ventilate well, and scout weekly.
• Succession: stagger plantings every 3-14 days depending on crop to ensure continuous harvest.
• Recordkeeping: track sow dates, germination rates, days to harvest, and yield to refine schedules for your specific Kansas location.

Final practical takeaways

Grow what matures quickly and what benefits most from greenhouse conditions in Kansas. Microgreens and baby leaf greens are the easiest and fastest returns, require little space, and fit both small and commercial operations. Pair those with quick root crops and high-turnover herbs to diversify income or home supply. Control temperature and light carefully, use succession planting aggressively, and maintain strict sanitation and ventilation. With these focused choices and practices you can keep a greenhouse producing frequent, reliable harvests through Kansas’s variable seasons.