10 Best Plants To Grow in a Greenhouse

Updated: Mar. 11, 2024

If your growing season is short, try growing these warm-weather plants in your greenhouse.

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Woman horticulturist working in farm glasshouse, harvesting fresh green tomatoesrbkomar/Getty Images

Do you live in a short season climate? If your growing season is less than 120 days, your climate is considered a short season. This can be due to various factors, such as too many cloudy days (common in the Pacific Northwest), fewer frost-free days (seen in parts of Idaho) or cool, dry nights at higher elevations (as found in Colorado).

In such areas, growing warm-season vegetables, herbs and fruits can be challenging without a greenhouse. Greenhouse structures, whether made of glass or plastic, amplify sunlight and convert it into heat, creating an ideal environment for these heat-loving plants to thrive.

“Greenhouses offer a barrier against pests and diseases, reducing the risk of infestations and promoting healthier plants,” says Carrie Spoonemore, co-creator of Park Seed’s From Seed to Spoon app. “Their ability to adapt will enable gardeners to grow a diverse selection of crops that might struggle in the local climate, making them invaluable for those looking to maximize yield and diversity in their garden.”

We’ve compiled a list of the best plants that can be successfully grown in a greenhouse, regardless of where you live.

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Lemons on the Tree Jennifer A Smith/Getty Images

Citrus Trees

Growing citrus trees to fruiting size can be difficult in short-season gardens, but they’re an ideal plant for a greenhouse with abundant sunshine and warm temperatures. Many citrus trees also bloom in winter, and the greenhouse protects these flowers from freezing.

  • Grow citrus trees in pots or directly in the ground if your greenhouse has a specific in-ground planting area.
  • Start with small trees from specialty nurseries like Logee’s Plants for Home and Garden. Note their mature size before placing your order.
  • Fertilize citrus trees once a week with a soluble organic fertilizer.
  • Citrus trees need a minimum temperature of 45 to 50 degrees, so your greenhouse will need supplemental heat in the winter.

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Tomatoes on vine Jed Share/Getty Images

Tomatoes

Love tomatoes but live too far north to grow them? Some gardeners start tomatoes in a greenhouse, then move them outside after the danger of frost has passed.

  • Unless you want tomato vines all along your greenhouse walls and ceiling, choose dwarf, container-friendly varieties like All-America Selection winner ‘Purple Zebra.’
  • Determinate (aka bush) tomatoes, like early-maturing Oregon Spring, are another good choice. They also grow shorter and produce their entire crop in a short period.

Here’s more advice for growing tomatoes to produce the best harvest.

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Ripe bell pepper in a greenhouse Westend61/Getty Images

Hot or Mild Peppers

Like tomatoes and eggplants, peppers are part of the Solanaceae or nightshade family. They need warm temperatures, long days and a long season to bring fruits to maturity. In a short-season climate, a greenhouse solves these problems.

  • Sweet peppers, like popular bell peppers, usually only grow 3- to 3-1/2-feet fall and 15- to 18-inches wide. Hot peppers usually grow from one to five feet tall depending upon the variety. Jalapeño peppers produce a lot of fruit on a smaller plant, growing two to three feet tall and 16- to 18-inches wide, so they’re ideal for containers. You only have so much room in a greenhouse, so smaller, high-production plants are better.
  • Try to choose varieties with high yield and disease resistance.
  • Some peppers like ‘Pot-a-peno‘ or ‘Candy Cane Chocolate Cherry were specially trialed to grow in containers.
  • With bell peppers, you need support like tomato cages to keep the fruit up and off the planting bench.
  • Sweetie Pie is a miniature sweet bell pepper that doesn’t need staking.

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three watermelons growing in the garden closeup Tianika/Getty Images

Melons

Like the other plants on this list, melons require six to eight hours of sunlight and heat for their vines to grow, flower and fruit. Watermelons, muskmelons (cantaloupe) and honeydew can all be grown in greenhouses.

  • Melons need well-drained neutral soil, so grow them in containers with good organic potting soil.
  • Melons are another group of vining plants that can take over a greenhouse. Choose varieties for container gardening like ‘Mini Love‘ watermelon, which has vines that only grow three to four feet.
  • Minnesota Midget‘ is a great, early-maturing small variety. There’s a whole group of micro-melons perfect for your greenhouse garden.

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Close-Up Of Wet cucumber Plant Leaves Miro V/Getty Images

Cucumbers

Cucumbers are a popular commercial greenhouse vegetable because they can be trellised to produce many fruits in a small space. Cucumbers are perfect plants to grow in your greenhouse.

  • Select disease-resistant, space-saving varieties that quickly mature from flower to fruit.
  • Although many types of cucumber seeds are available, including English, Asian and Armenian (actually a melon), the most common cucumbers fall into the slicer or pickling categories.
  • Slicing cucumbers are what you see in salads. Although pickling cucumbers can also be eaten raw, they’re better for pickles because they’re knobby and prickly.
  • For small gardens and greenhouses, you can’t beat small, vining bush types like ‘Spacemaster.’

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Ripe eggplants growing in the vegetable garden ozgurdonmaz/Getty Images

Eggplant

Eggplant is one of my favorite plants to grow because it tastes so much better than the kind you buy in the supermarket. In a short season or shady climate, growing eggplant in a greenhouse gives you the intense sunlight and heat to bring the fruit to maturity.

  • Instead of the classic Italian eggplant, grow an Asian variety like ‘Fairy Tale‘, which produces more fruit in a shorter time.
  • Eggplants need room, so plant only one per two-gallon pot in well-drained, good-quality organic potting soil.
  • Eggplants are heavy feeders. Use a soluble fertilizer once a week after they start to bloom.
  • Water them once or twice a week, depending on how hot your greenhouse gets.

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Nice ripe Zucchinis growing over garden ideeone/Getty Images

Summer Squash

Golden or green summer squash just tastes like summer. But if you live where summers aren’t that warm, it’s hard to grow these heat-loving plants. With a greenhouse’s radiant heat and copious sunshine, you’ll have much better luck getting plants to grow to their mature size.

  • Summer squash has a shorter growing season (45 to 60 days) than winter squashes like butternut and acorn (from 90 to 125 days).
  • Place containers beneath greenhouse grow tables for shade and near greenhouse fans for good air circulation.
  • Use a good soluble, organic fertilizer once a week when summer squash starts to flower. Once the sun is up, leave the greenhouse door open to admit pollinators.
  • Choose early-maturing, disease-resistant varieties like ‘Sunburst‘ that don’t take up much room.
  • Pick frequently to encourage more fruits.

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Fresh Basil Leaves Ali Majdfar/Getty Images

Sweet Basil

Sweet basil (aka culinary basil) is a great plant to grow in a greenhouse. Like other Mediterranean herbs, it needs six to eight hours of sun daily and loves the greenhouse’s radiant heat. You can start basil in a greenhouse and transplant it into the garden once the soil heats up.

  • Depending on the variety and container size, you may plant more than one per pot.
  • With three plants in one 14-inch pot, you could have basil all summer long.
  • Everleaf Emerald Towers is a superb smaller variety that rarely flowers or goes to seed.

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Close up image of rosemary growing in a garden gaffera/Getty Images

Rosemary

Rosemary is a perennial herb that grows wild on rocky hillsides in the Mediterranean, so it can handle the heat and plentiful sunshine of a greenhouse. If you’re growing rosemary in a short-season climate, overwinter it in the greenhouse.

  • Rosemary is drought tolerant and grows in poor soils. Go with cactus potting mix for container-grown rosemary.
  • In warm climates like USDA Plant Hardiness Zones 8 to 11, upright rosemary is an evergreen bush.
  • It can handle the heat of a greenhouse but doesn’t like humidity.
  • Don’t overwater it. Keep it near the greenhouse fan to whisk away extra moisture in the air.
  • Like other greenhouse plants, rosemary can benefit from shade cloth.

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Greenhouse Geraniums KenWiedemann/Getty Images

How to Decide What to Grow in Your Greenhouse

Geraniums

Some of my favorite greenhouse plants are scented pelargoniums, commonly called geraniums. True geraniums are perennials, but scented pelargoniums are basically their tropical cousins.

Geraniums are wonderful plants for a greenhouse because they’re drought tolerant and can handle fierce greenhouse heat in summer. In my climate, USDA Zone 7, it’s too hot to grow anything in a greenhouse in summer. Instead, I overwinter my geraniums, which cheerfully bloom in February and March before anything else is flowering outside.

  • Their foliage comes in scents from rose to apple to nutmeg. They smell great when you rub their leaves, and you can make flavored sugars and bath salts from them.
  • They bloom with small flowers that attract pollinators. (Always remember to leave doors and vents open to let pollinators in!)
  • They can handle high temperatures if watered regularly.
  • Assess your climate: Consider the weather conditions in your area and how they might affect greenhouse gardening. Factors like harsh winters, humidity levels and sunlight exposure influence the types of plants that thrive in your greenhouse.
  • Evaluate the space: Determine how much space you have in your greenhouse and plan accordingly. Some plants, like tomatoes and cucumbers, require more space to grow; while others, like herbs and lettuce, can be grown in smaller areas.
  • Identify your goals: Decide what you want to achieve. Are you looking to grow food year-round, start seedlings for outdoor planting or simply enjoy gardening as a hobby? Your goals will influence what greenhouse plants you choose.
  • Research plant requirements: Different plants have varying needs for light, temperature, humidity and soil. Research the requirements of the plants you’re interested in to ensure they are compatible with your greenhouse conditions.
  • Consider companion planting: Some plants grow better when planted side-by-side. Explore companion planting to maximize space, discourage pests and improve overall plant health.

Tips for Success

“Creating an optimal greenhouse environment requires diligent maintenance and care,” says Spoonemore. “Regularly inspect the structure to identify and address any damage promptly. Keep a close eye on the environment, checking for issues like temperature fluctuations, humidity levels and signs of pests or diseases.” Spoonemore also recommends implementing preventative measures such as cleaning, disinfecting and removing plant debris. This will minimize the risk of infestations and disease outbreaks.

  • Plant in containers with good potting soil.
  • Even in cooler climates, your greenhouse needs shade cloth, fans and ventilation to moderate high summer temperatures, which can climb above 100 degrees.
  • Leave the greenhouse door and vents open for pollination and ventilation.
  • Buy a recording thermometer that can hold data for more than 24 hours and update you on the temperature in the greenhouse via an app on your phone.
  • Combat excess humidity with a fan and good ventilation that can quickly dry out the air.
  • You’ll need supplemental heat if you intend to overwinter plants or start plants in spring and fall.
  • Check the structural integrity of the greenhouse regularly and repair damage to ensure safety and longevity.

Why You Should Trust Us

I’ve written about and extensively researched gardening, lawns and lawn pests. Other topics I’ve covered include the optimal temperature for a greenhouse and signs that you have moles in your yard.

For this piece, we consulted Carrie Spoonemore the co-creator of Park Seed’s From Seed to Spoon app. Her passion for growing food led her to create the app in 2017. She works to collect and share educational content through Park Seed and shares her gardening expertise on YouTube through videos she creates on her five-acre homestead.