Table of Contents
- Introduction
- The Benefits of Growing Begonias in a Greenhouse
- Understanding Begonia Types for Greenhouse Success
- Setting Up Your Greenhouse Environment
- Starting Begonia Tubers in the Greenhouse
- Potting and Soil Selection
- Watering and Feeding for Healthy Growth
- Guiding Your Begonias to Bloom
- Maintaining a Clean and Healthy Greenhouse
- Transitioning to Dormancy
- The Longfield Gardens Quality Promise
- Conclusion
- FAQ
Introduction
Walking into a greenhouse filled with the lush leaves and brilliant colors of begonias is one of the most rewarding experiences a gardener can have. Whether you are looking for the massive, rose-like blooms of tuberous begonias or the intricate, swirling patterns of foliage varieties, the greenhouse offers the perfect sanctuary for these tropical beauties. At Longfield Gardens, we believe that having a dedicated space to control the environment makes growing these stunning plants much easier and more enjoyable for everyone, and our Begonia Flower Bulbs for Sale collection is a great place to start.
This guide is designed for home gardeners who want to maximize their success by growing begonias in a greenhouse. We will cover everything from setting up the ideal environment and starting your tubers to managing growth and encouraging a spectacular show of flowers. Using a greenhouse allows you to extend your growing season and protect your plants from the unpredictable spring weather. For a head start, see How to Start Tuberous Begonias Indoors.
By understanding a few basic principles of light, temperature, and moisture, you can transform your greenhouse into a begonia paradise.
The Benefits of Growing Begonias in a Greenhouse
Greenhouses provide a stable microclimate that mimics the native tropical and subtropical habitats of begonias. In the wild, many begonias grow in the filtered light of forest floors where the air is warm and moist. A greenhouse allows you to recreate these conditions regardless of your local weather. For a broader overview of the genus, read All About Begonias.
One of the biggest advantages is the ability to start your growing season early. While outdoor gardeners must wait for the soil to warm and the threat of frost to pass, greenhouse gardeners can begin waking up tubers in late winter. This early start results in larger plants and a much longer blooming period once summer arrives.
Greenhouses also offer protection from common outdoor stressors. Heavy rain can damage delicate petals, and strong winds can snap the brittle stems of taller varieties. In a controlled space, your plants stay pristine and protected, allowing their natural beauty to shine without interruption.
Understanding Begonia Types for Greenhouse Success
Before you start planting, it is helpful to know which types of begonias thrive best in a greenhouse setting. While there are thousands of varieties, most home gardeners focus on a few reliable groups.
Tuberous Begonias
These are the superstars of the greenhouse. They grow from thick, potato-like tubers and produce some of the most spectacular flowers in the plant world. Tuberous begonias come in many forms, including upright varieties with massive "dinnerplate" blooms and pendula types that cascade beautifully over the sides of pots. They are seasonal plants that go dormant in the winter, making them perfect for greenhouse cycles. For a collection of upright, rose-like types, explore Upright Double Begonias.
Rhizomatous Begonias
Grown primarily for their stunning foliage, rhizomatous begonias have thick stems that grow along the soil surface. Their leaves come in an incredible array of colors, from deep chocolate and burgundy to bright silver and neon green. They appreciate the high humidity of a greenhouse and make excellent year-round residents.
Rex Begonias
A subset of the rhizomatous group, Rex begonias are famous for their swirling leaf patterns and metallic lusters. They are often grown as houseplants, but they truly flourish in the consistent humidity of a greenhouse. They prefer slightly cooler temperatures than some other tropical plants, which makes them easy to manage in a standard greenhouse setup. For a closer look at light levels, see Are Begonias Shade Plants? Light Tips for Best Blooms.
Wax Begonias
These are often seen as bedding plants in the landscape, but they perform exceptionally well in a greenhouse. They have waxy, succulent-like leaves and produce constant clusters of small red, pink, or white flowers. They are very resilient and can handle a bit more light than their tuberous cousins.
Key Takeaway: Choose tuberous begonias for spectacular seasonal blooms or rhizomatous varieties like Rex begonias for year-round architectural foliage.
Setting Up Your Greenhouse Environment
Success with begonias starts with getting the "Big Three" right: temperature, humidity, and light. Because begonias are sensitive to extremes, the goal is to create a consistent, moderate environment.
Temperature Control
Begonias generally prefer temperatures that humans find comfortable. During the day, aim for a range between 65°F and 75°F. At night, it is healthy for the temperature to drop slightly, but it should stay above 50°F.
If your greenhouse gets too hot in the summer, use shade cloths or fans to bring the temperature down. Begonia Upright Double Bertini is one of the more adaptable tuberous options for brighter conditions.
Humidity Levels
Begonias love moisture in the air. Ideally, you should maintain a humidity level between 50% and 70%. In a greenhouse, humidity often stays naturally high, but on dry or windy days, it may drop.
You can increase humidity by misting the floors or using gravel trays filled with water beneath your pots. Just be sure to maintain good airflow. High humidity combined with stagnant air can lead to fungal issues like powdery mildew.
Light Requirements
In their natural habitat, most begonias grow under a canopy of trees. They need bright, indirect light rather than harsh, direct sun. In a greenhouse, this usually means placing them on benches that receive filtered light.
If your greenhouse has clear glass or plastic, you may need to apply a shading compound or use a shade cloth during the brightest months of the year.
Starting Begonia Tubers in the Greenhouse
One of the most exciting parts of greenhouse gardening is starting your tubers in late February or March. This gives your plants a head start of several weeks over those planted directly outdoors.
Inspecting Your Tubers
When you receive your tubers from us, they should feel firm and heavy for their size. Look for the "hollow" side, which is the top where the sprouts will emerge. The rounded side is the bottom where the roots will grow. Sometimes you will already see small pink or white "pips" or buds starting to form in the hollow center.
The Pre-Sprouting Process
You do not need to plant tubers in their final, large pots right away. Starting them in shallow trays saves space and allows you to monitor their early growth more closely. For more step-by-step guidance, see Tips for Growing Tuberous Begonias.
- Fill a shallow tray with a light, well-draining starting mix, such as a blend of peat moss and perlite.
- Place the tubers on the surface of the mix with the hollow side facing up.
- Space them about 2 inches apart so their roots have room to spread.
- Press them gently into the mix, but do not bury them deeply. The tops of the tubers should remain just at or slightly above the soil surface.
- Lightly moisten the mix, being careful not to pour water directly into the hollow of the tuber, as this can cause rot.
Caring for New Sprouts
Keep the trays in a warm spot in the greenhouse, ideally around 70°F. Within two to four weeks, you should see small green shoots emerging. Once the shoots are about an inch tall and you see roots developing underneath, the tubers are ready to be moved into their individual pots.
What to do next:
- Check tubers for firm texture and visible "pips" before planting.
- Use a light, porous starting mix to prevent moisture from sitting against the tuber.
- Keep the hollow side of the tuber facing up and slightly exposed to the air.
- Maintain a consistent temperature of 70°F to encourage steady sprouting.
Potting and Soil Selection
When it is time to move your sprouted begonias into their permanent homes, the container and soil you choose will make a big difference in their long-term health.
Choosing the Right Pot
Begonias have relatively shallow root systems. They do not need extremely deep pots, but they do need plenty of room for their roots to spread horizontally. A standard 6-inch to 8-inch pot is usually sufficient for a single medium-sized tuber.
Both plastic and terracotta pots work well. Plastic holds moisture longer, which can be helpful in a dry greenhouse. Terracotta is more porous, which allows the roots to "breathe" better and can prevent the soil from staying too wet. No matter what material you choose, ensure the pot has ample drainage holes. For a cascading option suited to baskets, try Begonia Hanging Golden Balcony.
The Perfect Soil Mix
Begonias need soil that is rich in organic matter but drains very quickly. A heavy garden soil will pack down and suffocate the roots. Instead, use a high-quality, peat-based potting mix.
You can create a custom mix by combining two parts peat moss or coco coir, one part perlite, and one part finished compost. This provides the acidity begonias love, the drainage they require, and a slow release of nutrients to support growth.
Watering and Feeding for Healthy Growth
Proper watering is the most important skill to master when growing begonias in a greenhouse. Because they have succulent-type stems and tubers, they store water and can be sensitive to overwatering.
The "Deep Water and Dry" Method
Rather than giving your plants a small sip of water every day, it is better to water them thoroughly and then let the soil dry out slightly. Insert your finger about an inch into the soil; if it feels dry, it is time to water.
When you water, apply it directly to the soil surface. Try to keep the foliage and the center of the tuber dry. This simple step helps prevent common issues like leaf spot and tuber rot. In a greenhouse, evaporation happens faster on sunny days, so check your pots more frequently during a heatwave.
Nutrient Balance
Begonias are moderate feeders. They need nutrients to build strong stems and lush leaves before they can put energy into flowers. When the plants are young and growing leaves, a balanced water-soluble fertilizer (such as a 10-10-10 or 20-20-20) works well.
As the plant matures and you see the first flower buds forming, you can switch to a fertilizer with a higher middle number (phosphorus), such as a 10-30-20. This encourages the plant to produce more and larger blooms.
Guiding Your Begonias to Bloom
While begonias will naturally flower as they mature, greenhouse gardeners can use simple environmental cues to encourage a more spectacular display. This is sometimes called "stress management," but it is really just about guiding the plant's life cycle.
Light Duration
Tuberous begonias are sensitive to the length of the day. They naturally flower when days are long. In early spring, if your greenhouse is very dark, supplemental lighting can help the plants grow more leaves. Once the natural days reach 12 to 14 hours of light, the plants will naturally transition into their blooming phase.
Managing Nitrogen
If your begonia has plenty of dark green leaves but no flowers, you might be giving it too much nitrogen. Nitrogen promotes leaf growth, while phosphorus promotes flowers. Reducing the amount of nitrogen and increasing the phosphorus can "nudge" the plant into its reproductive stage.
Moisture Cycles
In a professional greenhouse, growers sometimes let the soil get slightly drier than usual once the plant has reached its full size. This minor "stress" tells the plant that it is time to produce seeds and flowers. You don't want the plant to wilt, but allowing the soil to dry a bit more between waterings in mid-summer can result in a sudden burst of blooms.
Key Takeaway: For the best flowers, switch to a high-phosphorus fertilizer once you see buds and ensure your plants get at least 12 hours of bright, indirect light.
Maintaining a Clean and Healthy Greenhouse
A clean greenhouse is a healthy greenhouse. Because begonias thrive in the same humid conditions that fungi love, a little bit of housekeeping goes a long way.
Airflow is Essential
Even on cool days, try to keep the vents in your greenhouse cracked open. Stagnant air allows moisture to sit on the leaves, which invites disease. Small oscillating fans can also help keep the air moving around your plants, strengthening the stems and preventing mold.
Grooming Your Plants
Begonias are generally "self-cleaning," meaning they drop their spent flowers on their own. However, in a greenhouse, these dropped petals can land on leaves and rot, potentially causing damage to the healthy foliage. Spend a few minutes each week picking up dropped blooms and removing any yellowing or damaged leaves. This keeps the plant looking its best and removes potential hiding spots for pests.
Identifying Common Pests
While begonias are relatively pest-resistant thanks to the oxalic acid in their leaves, they can occasionally attract unwanted guests.
- Aphids: Small, soft-bodied insects that cluster on new growth.
- Spider Mites: Tiny pests that thrive in hot, dry conditions and leave fine webbing.
- Mealybugs: White, cottony insects that hide in the junctions of stems and leaves.
If you spot these, a gentle spray of insecticidal soap or neem oil usually solves the problem. Always follow the label instructions and test a single leaf first, as begonia foliage can be sensitive.
Transitioning to Dormancy
As the days grow shorter in the fall, tuberous begonias will naturally begin to wind down. This is a normal part of their life cycle. The leaves may begin to turn yellow, and the plant will stop producing new flowers.
Preparing for Winter
When you see the foliage starting to fade, gradually reduce your watering. This signals to the tuber that it is time to store energy for the winter. Once the stems have completely yellowed or fallen off, carefully lift the tubers from their pots.
Storage Tips
Gently brush off the excess soil, but do not wash the tubers with water. Let them sit in a dry, shaded spot in the greenhouse for a few days to "cure." Once the outer skin feels dry, store them in a cool, dark, and frost-free place. A box filled with dry peat moss or sawdust works perfectly. Check on them once a month during the winter to ensure they stay firm and dry. If you want to compare your climate before overwintering, use the Hardiness Zone Map.
The Longfield Gardens Quality Promise
At Longfield Gardens, we want every gardener to feel the joy of a successful harvest or a blooming flower bed. We work with trusted growers in major bulb-growing regions, including Holland, to ensure you receive the highest quality plants. See our Shipping Information for delivery timing and details.
We stand behind the quality of our products with a 100% Quality Guarantee. We ensure that our items are true to variety and arrive at your door in prime condition. If you notice any damage or quality issues upon delivery, please contact our responsive customer service team promptly. If your plants do not perform as expected during their first growing season, we are here to help with solutions, which may include replacements or store credit depending on the situation.
Conclusion
Growing begonias in a greenhouse is a wonderful way to bring a touch of the tropics into your backyard. By providing a stable environment with moderate temperatures, high humidity, and filtered light, you can enjoy some of the most beautiful flowers and foliage available in the gardening world. Whether you are starting with a single pot of Rex begonias or a full collection of cascading tuberous varieties like Begonia Upright Double Roseform Pink, the process is rewarding and accessible for gardeners of all levels.
- Start tubers early in the greenhouse for a longer blooming season.
- Focus on moisture management to prevent rot and promote health.
- Use a high-phosphorus fertilizer to encourage a massive display of blooms.
- Keep the greenhouse clean and well-ventilated to avoid common issues.
Growing begonias in a controlled environment allows you to see the true potential of these plants, resulting in larger blooms and healthier foliage than you ever thought possible.
We invite you to explore our selection of premium begonia tubers, including Begonia Non Stop Mix - Bulk Offer, and start your greenhouse journey today. With a little bit of care and the right environment, you will be rewarded with a spectacular display of color all season long.
FAQ
When should I start my begonia tubers in the greenhouse?
You can start pre-sprouting your begonia tubers in the greenhouse as early as late February or March. This gives them a significant head start over the outdoor growing season, leading to earlier and more prolific flowers. Ensure your greenhouse can stay above 50°F at night before you begin the process.
How much light do begonias need when grown in a greenhouse?
Begonias prefer bright, indirect light. In a greenhouse, this often means they should be placed where they receive filtered sunlight, such as under a shade cloth or in a spot that doesn't get hit by the intense midday sun. If the leaves look scorched or turn brown, the light is likely too direct.
Why are my begonia leaves turning yellow in the greenhouse?
Yellowing leaves are often a sign of overwatering or poor drainage. Begonias like consistent moisture but cannot sit in soggy soil. Check to make sure your pots have drainage holes and that you are allowing the top inch of soil to dry out between waterings. Yellowing can also occur naturally in the fall as the plant prepares for dormancy.
Do I need to fertilize my greenhouse begonias?
Yes, begonias benefit from regular feeding during the growing season. Use a balanced, water-soluble fertilizer every two weeks while the plant is growing leaves. Once you see flower buds appearing, switch to a high-phosphorus fertilizer to support large, vibrant blooms. Always dilute the fertilizer to half-strength to avoid burning the roots.