Begonias from Seed: Expert Tips for Successful Propagation
You are interested in growing begonias from seed but discouraged by the low germination rate. If I got that right, this guide is for you. Starting begonias from seed may seem complex, but it’s not. All that is required is seeds, soil, and proper growing conditions. In our article below we will take you through all the specifics to ensure that your efforts to grow your own begonias from seed prove fruitful and your gardens are rewarded with a bevy of beautiful flowers come spring.
Begonias can be a bit picky, but only because they require a specific growing environment. If you give them what they need, they’ll grow well, and you’ll be thrilled with how they turn out.
Here are the secrets for germinating begonia seeds at home:
- Warm temperature (70-75°F). A growing mat is usually required for consistent temperature.
- High humidity (>70%)
- Bright, indirect light
- And moist, well-draining seed-starting soil
We will explain each step and provide some do’s and don’ts to help prepare them for successful spring gardening.
Necessary Supplies for Seed Starting
Quality Seeds
Growing begonias from seeds requires high-quality begonia seeds, which you can obtain from reputable suppliers. Ensuring fresh seeds is crucial, significantly increasing the chances of successful germination.
There are also many different types of begonias, each with unique characteristics and growing requirements. Some popular types include tuberous begonias, which produce large, showy flowers and are ideal for containers or hanging baskets. Rex begonias are known for their striking foliage, intricate patterns, and vibrant colors. And our favorite, semperflorens begonias, used as bedding plants due to their continuous blooming nature. Choose your seeds based on your specific climate and display needs, and get planting!
Seed-Starting Mix
Another crucial supply for starting begonias from seed is a quality seed-starting mix. This specialized potting mix provides the texture and nutrients necessary for successful germination and early growth. Unlike regular garden soil, seed-starting mixes are formulated to be lightweight, sterile, and provide excellent drainage—essential for healthy seedling development.
Look for a mix specifically designed for starting flower seeds or one labeled as suitable for delicate plants like begonias. These mixes often contain ingredients such as coconut coir, peat moss, perlite, vermiculite, providing an optimal environment for young begonia plants.
Containers
Selecting the proper containers is vital when starting begonias from seed. Opt for small pots or trays with suitable drainage holes at the bottom to prevent waterlogging—the leading cause of seedling failure. Using individual cells or small pots helps minimize root disturbance when transplanting young begonia plants into larger containers later.
Consider using biodegradable pots or compressed soil pellets that can be planted directly into larger containers once the seedlings have matured. These options eliminate the need to disturb delicate roots during transplantation while promoting eco-friendly gardening practices by reducing plastic waste.
Light Source
Adequate light is critical during the early stages of growing begonias from seed. If natural sunlight is limited in your location (especially during late winter/early spring), consider investing in fluorescent grow lights specifically designed for starting seeds indoors.
Sowing Begonia Seeds Correctly
Proper Timing
Start sowing indoors 10-12 weeks before the last frost date in your area. This time allows the seedlings to grow and develop into robust plants when ready for outdoor planting.
Sowing too early can lead to leggy seedlings that struggle to thrive outdoors, while sowing too late may not give the plants enough time to mature. By timing your begonia seed sowing correctly, you ensure that the young plants have optimal conditions for growth and development.
Seed Planting Depth
When sowing begonia seeds, it’s essential to plant them at the correct depth for successful germination. The recommended planting depth for begonia seeds is about 1/8 inch deep. This depth ensures they receive sufficient light, which is crucial for their germination process. For tuberous begonias, the recommendation is to press the seeds into the top level of the soil.
Planting begonia seeds too deeply can result in poor or no germination because they don’t receive enough light. On the other hand, planting them too shallow might overexpose them and affect their moisture levels. Therefore, ensuring an ideal planting depth is vital for giving begonia seeds a favorable environment for sprouting.
Lighting and Temperature for Optimal Growth
Importance of Light
Light is crucial for the growth of begonias from seed. It provides the energy needed for photosynthesis, essential for plant growth. Without adequate light, begonia seeds may struggle to germinate and develop into healthy plants.
Begonias thrive in bright but indirect light. Direct sunlight can be too hard and damaging to the delicate seedlings. Placing the plants near a window with sheer curtains or using artificial grow lights can provide the ideal lighting conditions.
Ideal Temperature Range
Maintaining the correct temperature is also vital when growing begonias from seed. These plants prefer warm conditions but are sensitive to extreme heat or cold.
The optimal temperature range for begonia seed germination is between 70-75°F (21-24°C). Consistently warm temperatures promote successful germination and healthy growth of young begonia plants.
Providing Consistent Conditions
Consistency in lighting and temperature is key to ensuring the successful cultivation of begonias from seed. Fluctuations in either factor can negatively impact germination rates and overall plant health.
To achieve this consistency, consider using a heat mat to maintain stable soil temperatures during germination. Regularly monitor indoor temperatures if growing in a controlled environment.
Seasonal Considerations
When starting begonia seeds indoors, it’s important to mimic their preferred outdoor growing conditions as closely as possible. This includes considering seasonal changes in natural light and temperature.
When natural daylight hours are shorter in winter, supplementing with artificial grow lights becomes necessary to provide sufficient illumination for the developing seedlings. In contrast, during summer, it’s crucial to shield young plants from intense direct sunlight by adjusting their positioning or providing shade during peak daylight hours.
Caring for New Begonia Seedlings
Watering
Begonia seedlings need consistently moist soil. Water them when the top inch of soil feels dry. Overwatering can lead to root rot, while underwatering begonias can cause stress and stunted growth.
It’s crucial to strike a balance in watering begonia seedlings, as they are sensitive to both extremes. Consider using a spray bottle or a watering can with a fine spout to maintain moisture levels.
Fertilizing
When begonia seedlings have developed their first set of true leaves, fertilize them every two weeks. Use a balanced liquid fertilizer diluted to half-strength to avoid overwhelming the delicate roots.
Fertilizers provide essential nutrients from seeds for healthy growth and vibrant blooms in begonias. However, over-fertilization can result in burnt foliage or excessive vegetative growth at the expense of flowers.
Transplanting and Acclimatizing Young Begonias
Transplanting Process
You must transplant young begonia seedlings into individual pots if you want them to grow well. Once the begonia seedlings have developed their first set of true leaves, they are developed enough to be transplanted. Gently lift the delicate seedlings out of their original container, careful not to damage the roots. Prepare small pots filled with well-draining potting mix, then create a hole in the center using your finger or a tool. Carefully place each seedling into its new home and lightly pat down the soil around it to secure it in place.
Acclimatizing Process
Acclimatizing young begonia plants is essential for preparing them for life outdoors or in less controlled environments. Begin by placing the potted begonias outside for short periods each day, gradually increasing exposure over one to two weeks until they spend most of their time outdoors. Start by putting them in a shaded area and slowly introducing more sunlight as they adjust.
It’s important not to rush this acclimatization process; gradual exposure helps build tolerance against environmental factors like wind and direct sunlight while reducing plant shock when transitioning from indoor conditions.
Expert Tips
Here are our best tips to help you navigate your begonia growing journey – these tips will help prevent issues. They can help troubleshoot any problems you may encounter.
- Use a Sterile Seed Starting Mix: Begonia seeds are extremely fine and can be easily overwhelmed by fungi and bacteria in the soil. Using a sterile seed starting mix reduces the risk of diseases.
- Provide Consistent Warmth: Begonias germinate best in warm conditions. Using a gardening heat mat to maintain a consistent temperature between 70-75°F (21-24°C) is a great way to ensure germination.
- Lightly Cover Seeds: Due to their tiny size, begonia seeds need light to germinate. Lightly press them into the soil surface, but do not bury them.
- Use a Humidity Dome: Cover the seed tray with a clear plastic cover or plastic wrap to maintain high humidity, which is crucial for germination.
- Avoid Direct Sunlight: Place the seed tray in a location with bright, indirect light. Direct sunlight can overheat and damage the delicate seedlings.
- Gentle Watering: Water using a fine mist to prevent disturbing the tiny seeds. You can also water from below by placing the tray in a shallow bath, allowing the soil to absorb moisture from the bottom.
- Thin Seedlings Early: Once seedlings develop a couple of true leaves, thin them to prevent overcrowding, which can lead to disease.
- Feed with Diluted Fertilizer: After the seedlings have a few true leaves, feed with a half-strength balanced liquid fertilizer every two weeks.
- Gradual Acclimatization: Gradually acclimatize the seedlings to less humid conditions before transplanting to reduce shock.
- Transplant Carefully: When seedlings are large enough to handle, transplant them carefully into individual pots, held by the leaves, not the delicate stems.
Frequently Asked Questions
Yes, you can use a high-quality, well-draining potting mix. A blend of peat moss, perlite, and vermiculite is ideal for begonia seed starting, providing moisture retention and aeration.
Begonia seeds typically germinate within 14 to 21 days when kept at an optimal temperature range of 70-75°F (21-24°C) and provided with consistent moisture.
Yes, providing bright but indirect light is crucial for healthy begonia seedlings. Consider placing fluorescent grow lights near a south-facing window to ensure proper growth.
Common challenges include overwatering, which can lead to damping off, and inadequate light, causing leggy growth. Maintaining consistent humidity levels is essential for successful propagation.
Once your begonias have developed their second set of true leaves and are around 2 inches tall, they can be transplanted into individual pots or cell packs. The second set of leaves usually occurs about 6-8 weeks after sowing.
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Final Remarks
You’ve now mastered the art of starting begonias from seed! With the right seeds, supplies, and know-how, you’re ready to begin your begonia-growing journey. Remember, patience is key. As you embark on this adventure, don’t be disheartened by any initial challenges. Instead, embrace them as part of the learning process. Remember that even the most experienced gardeners faced setbacks at some point. Now, get your hands dirty and watch those begonias flourish!
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Editors Note: This post was written on January 20th, 2018, and updated on January 30th, 2024. The newest update includes better formatting, a full rewrite, and information for transplanting and climatizing new seedlings grown from seed.
Author: Laura Kennedy
Writer & Owner of Little Yellow Wheelbarrow
Hi there Laura. I’m a year late so hope you still get this! My begonia seeds geminated the beginning of February 2022 (I sowed them 18/ Jan) and they still only have small 1 set of leaves germinated (with 2 little leaves). I’ll leave them another couple of weeks, but should I be doing anything to help them grow, or just be patient? Thank you. Emma
Hi Emma, begonias can be tricky for germination, but it looks like you had good luck. They start slow, but they take off pretty quickly. They are shade plants but still require some sun to grow, so be sure that they get at least 4 hours a day of sun, don’t overwater (overwatering will cause rotting, damping off, and ultimately their demise). When I start my begonias in January, they are out of control and taking over my house by the time May rolls around. I would be concerned if you didn’t see good growth over the next few weeks. If you want, you can send me a picture, and I can take a look to make sure nothing is off. I’d be concerned if there were mold on the soil or if the plants had weak necks and were falling over, but if the leaves are there and everything else is grand, they should do fine. I hope that helps!
Thank you for the inspiration! What date do you start this process?
Hi Sarah, I start now for planting around May 21st. By the time I put them in my window boxes the 6-inch pots I finish the plants in are nice and full. The plants take up a lot of space by the time May rolls around. You do not need to start this early, even mid-Feb will give you a nice size starter to plant. They grow fairly quickly too. They are by far my favorite for shade, they are a beautiful riot of color all summer long. Cheers!
I spend a fortune buying flowers for my gardens each year. I would like to try starting them from seed next year. I live in upstate New York. When would I need to start the wax begonia seeds so that they would be large enough to plant outside at the end of May? Also, can I save seeds from the plants that I currently have growing in my garden this year?
Hi Cynthia! I am in the ” spend too much on flowers every year ” club too. Start your begonia seeds at the start of January. That’s when I start mine for late May planting. The challenge with begonias is germination. I plant 100’s of seeds in flats to get 50-100 plants each year so just keep that in mind. Buy more seeds then you think you will need because not all of them will germinate. Saving seeds is a hit or miss type deal. If the original plants were hybrids the seeds collected may not produce the same type of plant. You never know what you’re going to get when harvesting seeds from hybrids, but you can try.
I have a yellow begonia in a pot plant. I water it once a week and I’ve had it for almost 2 months. when I initially had it, it has flowers but since those initial ones, it’s not producing anymore flowers. I do check for dead leaves and remove them to prevent it from being strained, but as soon as new flowers bloom, they get brown while small and eventually die. They don’t blossom into fully grown flowers. What could be the problem?
I’ve just added organic fertilizer a day ago, I’m keeping my fingers crossed but any help I’d appreciate. I love my flower. The leaves are nice and green and big but flowers just die 🙁
Hi ValF, it is tough to say without knowing what kind of Begonia you have, there are serval different types of begonias, some do make fantastic house plants, but others are intended to go outside. Several factors can make the plants drop their flowers, overwatering is a big issue. Begonias (regardless of type) do not like to have constant wet roots, and overwatering can cause the roots to root, which would cause the plant to drop the flowers. But you say the plant is healthy with bright green leaves, and if it looks healthy it is likely not an overwatering issue. The other thing is light, they are fussy little beasts. Too much natural light will cause them to drop flowers, so if the plant is in a window that gets strong natural light try moving it to another location. Alternately if the plant resides in a very dark area, it may be requiring a bit more natural light. You said you fertilized it, that’s a good step, they should be fertilized monthly and if you haven’t been that could also be why. Since the flowers are not reaching maturity it has to be a lack or overabundance of something throwing off the natural growth cycle. The only other thing I can think of is that the plant could be root bound and require transplanting into a larger pot. When I am growing my begonias for my summer beds, I find if I don’t transplant up they get root bound pretty quick and struggle, so that could be the problem too. Again, throwing out things it could be, without knowing for sure what type of begonia it is a shot in the dark. Good luck with your begonia!
How long does it take after germination for wax begonias to develop true leaves? I have a tray of seedlings under a grow light that have had their two tiny germination leaves for about two weeks but have not yet developed true leaves. Is that normal? I don’t have them on a heat mat and am going to remedy that soon.
Hi Elizabeth, They take a few additional weeks and I found it was sporadic, once those true leaves start and you start potting up it is amazing how fast they seem to grow. I wouldn’t add a heating mat at this point, the mat is really intended to help germination, after that the heating mat is to be removed, or else it might get too warm for your little seedlings. At this stage, keep the soil moist and give them plenty of light. So long as your seedlings look healthy you should start to see true leaves soon.
I want to give my bunco ladies a begonia in May. Can I plant seeds in the biodegradable 3 inch pots?
Hi Penny, you absolutely can use biodegradable 3-inch pots. I would keep the tops covered with plastic wrap to keep in the moisture and if you are not using a heating pad, keep them in a warm place. Germination of begonia seeds tends to be low, so I would hedge my bets by adding a few extra seeds to the pot. If you happen to get good germination you can always transplant the seedlings into other pots after they have 5 leaves.
Thanks for sharing your begonias! I could envision everything except the very last part part “WHAT TO DO WITH YOUR BEGONIA TUBERS IN SPRING”. The double bag confused me. Can you add pictures of that and also wondering why you use the cooking spray? Thank you!!
Hi Janet, I am about to plant some tubers this week in paper bags to get a jump on the season. I will have some additional photos to add to the post once I get them all planted. The pictures will make my words much clearer, and I will have those photos up before Friday.
I use the cooking spray to give the paper bags a bit of water resistance to make them last a bit longer. I don’t want the paper bags to deteriorate while I am waiting for my tubers to sprout. The cooking spray was a tip from a fellow gardener. I thought it was odd at the time when she told me about it, but it is a great little trick! The bags last until it is time to plant in the ground. The tubers stay in their paper bags when you plant them out. Planting this way makes transplanting a breeze!
I love begonias and bought 3 small vases last year, but they got mildew… I’m looking for more now.
I would like to see step by step photos of how you grow them from seeds, so I can start that as well.
Thank you!
Hi Marcia, begonias, unfortunately, are prone to powdery mildew. The advice that I follow is to always water from the bottom and don’t overwater. So for your indoor begonias using a small saucer of water under your container works best.