What To Grow In A Greenhouse

What to grow in a greenhouse depends on your goals, whether you're cultivating vegetables, fruits, herbs, or flowers. This guide explores the best greenhouse crops for beginners and experts, with tips on planting, care, and harvesting. Discover how to maximize your greenhouse's potential for year-round gardening success.

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• Best Plants to Grow in a Greenhouse
• Why Greenhouses Work
• packaged into plastic containers or without.
• 🌱 Greenhouse Gardening Tips
• 💬 Feedback

Greenhouse farming is a great way to economize on the use of space in your backyard, or if you’re into medium-scale farming, it’s a viable way to grow crops off-season.

Globally, greenhouses have become the default method of growing many kitchen garden vegetables. In this guide, we’ll explore the best plants for greenhouse gardening, tips for their care, and suggestions tailored to different climates and skill levels.

Best Plants to Grow in a Greenhouse

Vegetables

1. Tomatoes

• Best for: Beginners and experts
• Growing Conditions: Full sun, 70–85°F, consistent watering during fruiting.
• Care Tips: Use trellises or cages for support. Practice crop rotation to avoid soil-borne diseases. Hydroponic systems can work well for soil-free growth.
• Harvesting: Pick tomatoes when they are firm and fully colored.

2. Peppers (Sweet and Hot)

• Best for: Intermediate gardeners
• Growing Conditions: 70–80°F with high humidity during early growth stages.
• Care Tips: Water consistently but avoid waterlogging. Hand pollination can increase yields.
• Harvesting: Harvest when the peppers are firm and glossy.

3. Leafy Greens (Spinach, Kale, Lettuce)

• Best for: Beginners
• Growing Conditions: Cooler climates, moderate sunlight, and regular watering.
• Care Tips: Avoid overcrowding to reduce the risk of disease.
• Harvesting: Cut outer leaves as needed or harvest the entire plant when mature.

4. Microgreens

Harvesting: Ready 2–4 weeks after sowing when seedlings are 1–3 inches tall.

Best for: All skill levels

Growing Conditions: Partial sunlight, 60–70°F, nutrient-rich soil or hydroponic medium.

Care Tips: Keep soil moist and avoid overwatering.

Fruits

5. Grapes

• Best for: Experienced gardeners
• Growing Conditions: Warm temperatures, good ventilation, and support from trellises.
• Care Tips: Prune regularly to manage growth and reduce fungal risks. Hand-pollinate if necessary.
• Harvesting: Pick when grapes are plump and sweet.

6. Strawberries

• Best for: All skill levels
• Growing Conditions: Bright, indirect sunlight, temperatures between 60–80°F, and well-draining, nutrient-rich soil.
• Care Tips: Use containers or hanging baskets for better control of pests and soil conditions. Keep soil consistently moist and fertilize with a balanced fertilizer during the growing season.
• Harvesting: Pick strawberries when they are fully red and fragrant, typically 4–6 weeks after flowering.

7. Figs

• Best for: Intermediate to experienced gardeners
• Growing Conditions: Warm temperatures (65–75°F), good ventilation, and a potting mix with excellent drainage.
• Care Tips: Use a large container or plant in the soil for robust root development. Prune annually to encourage fruiting. Protect from frost in colder climates.
• Harvesting: Pick figs when they are soft to the touch and fully ripe, typically late summer to early fall.

Herbs

8. Basil, Mint, and Parsley

• Best for: Beginners
• Growing Conditions: Moderate sunlight, 60–75°F, well-draining soil.
• Care Tips: Harvest leaves regularly to encourage growth. Avoid overwatering.
• Harvesting: Snip leaves as needed or cut back the plant for larger harvests.

Flowers

9. Orchids

• Best for: Advanced gardeners
• Growing Conditions: Indirect sunlight, high humidity, and well-draining orchid potting mix.
• Care Tips: Mist regularly and avoid overwatering. Fertilize every 2–4 weeks with a balanced orchid fertilizer.
• Harvesting: Flowers can be cut once fully open for decorative use.

10. Geraniums

• Best for: Intermediate gardeners
• Growing Conditions: Bright, indirect sunlight, moderate temperatures (65–75°F), and a well-draining soil mix.
• Care Tips: Deadhead spent flowers to encourage blooming. Water when the top inch of soil feels dry.
• Harvesting: Cut flowers as needed for arrangements or allow them to bloom continuously in the greenhouse.

11. Marigolds

• Best for: Beginners
• Growing Conditions: Full sun, temperatures between 65–85°F, and nutrient-rich, well-draining soil.
• Care Tips: Marigolds are low-maintenance and pest-resistant. Water at the base to prevent fungal diseases.
• Harvesting: Pick flowers when fully open for use as decoration or garden borders.

12. Petunias

• Best for: Beginners to intermediate gardeners
• Growing Conditions: Bright, direct sunlight, temperatures between 60–75°F, and well-draining soil.
• Care Tips: Pinch back stems to encourage bushy growth and more blooms. Fertilize with a water-soluble fertilizer every 1–2 weeks.
• Harvesting: Flowers can be left to bloom continuously or cut for arrangements.

Why Greenhouses Work

Greenhouses create a controlled environment by regulating four key factors crucial for plant growth:

• Light. Traps UV light to fuel photosynthesis and warm the interior, boosting plant metabolism and growth.
• Temperature. Maintains optimal warmth for faster crop development, even during off-seasons.
• Water and Nutrients. Ensures consistent hydration and nutrient delivery for healthy plants.
• Air Circulation. Facilitates carbon dioxide exchange while managing humidity to prevent pests and diseases.

These conditions make greenhouses ideal for cultivating a wide range of crops, from leafy greens to flowering plants.

Factors Regulating Crop Growth Inside A Greenhouse

If you want to get into specifics and the science behind these four key factors, here's an explanation.

1. Light

Light is a crucial component of photosynthesis, the process by which plants make their food. Greenhouses regulate the light intensity, which in turn affects how much starch they build up and, therefore, how fast they can develop. Starch is important during a plant’s reproductive phase as it helps flowering.

During periods of high light intensity carbohydrate metabolism takes place very fast so that the plant is able to elongate and reach maturity faster, this is why crops grow faster in sunny weather than in winter.

2. Temperatures

What makes greenhouses so effective in speeding up the growth rate of plants is that they trap UV light and warm up the structure's interior. This is what is known as the greenhouse effect. Once these temperatures are raised, respiration takes place at a faster rate, which in turn speeds up the plant's metabolism.

Inevitably, higher temperatures go hand in hand with faster transpiration – the loss of water to the atmosphere – which, if unchecked, can lead to wilting of the plant. Therefore, transpiration needs to be compensated for by having an irrigation system to replenish the plant’s water and nutrients.

3. Water and Nutrients

Water is an important component of carbohydrates and also plays a role in the translocation or movement of carbohydrates or starch from the leaves to the roots and other growing parts of the plant.

Nutrients, on the other hand, are involved in synthesizing proteins and other building blocks of the plant, which are important for its development. Nutrients are taken up from the soil through the root system.

The soil type or media you use for growing your crop matters a lot in determining the availability of crucial nutrients for use by the plant. This presence is what we generally term soil fertility.

4. Air Circulation

The other important ingredient during photosynthesis is carbon dioxide. Plants combine carbon dioxide and water in the presence of light to make starch.

The greenhouse effect mentioned earlier is important in building up carbon dioxide within the greenhouse, which in turn increases starch metabolism.

Also, humidity builds up within the greenhouse when there’s a high transpiration rate. The buildup of humidity and low air circulation encourage the development of pests and diseases.

This may be done by incorporating shade nets within the greenhouse design to encourage ventilation.

Market Gardening vs. Export Production

Vegetables can be grown to sell locally at the grocery store or for export. In the former, the vegetables are sold at the farm gate or may be transported to the nearest town for sale in the market. In the case of export, these are normally processed and packed before export for use by big supermarket chains.

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🌱 Greenhouse Gardening Tips

1. Climate. Adapt plant choices to your local climate. For colder zones, focus on cool-season crops like leafy greens. In warmer zones, opt for tomatoes, peppers, and tropical fruits.
2. Greenhouse Types Choose the right greenhouse type for your needs. Glass greenhouses provide excellent light but are more expensive. Polycarbonate greenhouses are affordable and durable but may require supplemental lighting.
3. Sterilize your soil. Sterilize soil between growing seasons to reduce pest and disease risks.
4. Ventilation and watering. Ensure proper ventilation to manage humidity and prevent diseases.Use drip irrigation systems for consistent watering.

With some planning and effort, you can enjoy a bountiful harvest of fresh, delicious vegetables all year round.

Ready to start your greenhouse gardening journey? Share your favorite greenhouse crops or tips in the comments below. Don’t forget to explore our other guides on greenhouse maintenance and year-round gardening.