How to Grow Potted Bulbs Indoors
Growing potted bulbs is a great way to brighten up your indoor garden over the cooler months and enjoy spring flowers before they emerge outdoors. Gardening expert Madison Moulton provides a step-by-step guide to growing potted bulbs indoors.
The wait for spring can be long and arduous for gardeners. During those cold and gloomy winter months, I’ll do anything for a taste of spring to drum up excitement for the season. That’s where potted bulbs come in handy.
If you simply can’t wait for spring, why not grow your bulbs indoors over the fall and winter? Through a process known as forcing, you can enjoy the intricate flowers of hyacinths, daffodils, and a range of others in your indoor garden.
There are a few essential steps to ensure they flower at the right time. Here’s how to get it right.
Successful flowering starts with choosing the perfect bulbs to grow indoors. Luckily, growing most types indoors (even the fussier ones) is possible if you can provide the right conditions.
Some are more commonly grown indoors, including:
The level of maintenance required to induce flowering will depend on the types you choose. Most must be chilled before flowering for a certain period (covered in the forcing section below), while warm-region species like paperwhites and amaryllis don’t need pre-chilled. Part of choosing the right bulb is deciding how long you want to wait for flowers and how much work you will put in.
While a display of just one indoor variety is stunning, I like combining a few different types in separate containers. If you chill them at slightly different times, you’ll enjoy a continuously changing display that is always in flower.
No matter what flowers you choose, it’s important to ensure they are healthy and viable before planting. You don’t want to go through the planting process and care only to find they never sprout.
Signs of a Healthy Bulb
Whether using previously stored bulbs or purchasing new ones, there are a few signs of health to look out for.
Healthy bulbs will be firm to the touch without mushy or sunken spots.
No Signs of Disease
Don’t plant if they are discolored, mushy, or moldy.
Severe shriveling is a sign of lack moisture. These will struggle to grow after planting without rehydration.
Larger bulbs typically grow into stronger plants with better flowers.
For the strongest start, ensure they are healthy and primed for planting. You can still plant smaller or slightly shriveled ones and hope for the best, but avoid planting any with pests or diseases to stop the issue from spreading.
Depending on your chosen varieties, you may need to chill them before planting to encourage them to flower. This process is known as forcing, as you are forcing the plants to flower slightly earlier than they naturally would outdoors.
The chill time is based on the typical flowering time and region – in other words, how many weeks of cold they typically receive in their native habitats before they begin to flower.
Flowers that bloom first in spring and come from cold climates, like crocus, usually need around eight to ten weeks of chilling time minimum to flower. Those that bloom in the middle of spring, like some daffodils, will need around 12 weeks (often longer), and late-spring bloomers, like tulips, need around 15 weeks of chilling time. After this chilling period, they will flower within about three weeks.
The easiest way to chill is to pop them in the refrigerator in a mesh bag to promote airflow. Don’t store them with ripening fruits, as ethylene can interfere with the growing process. You can also leave them in your home’s basement or a cool room if temperatures are around 40F.
It’s also possible to chill bulbs inside their pots, either in a cool room or outdoors if you have the space. Managing temperatures is the most important aspect of the process if you want them to flower at a certain time, so the storage method is up to you.
After this chilling period, it’s time to plant in their new containers. The change in temperature to a warmer and brighter spot will tell them it’s time to produce new growth and prepare for flowering.
You can plant in almost any container indoors, as long as it is deep enough to accommodate the root system. Pots with drainage holes are recommended to allow any excess moisture to escape, preventing bulb rot.
But if you don’t want to go the traditional pot route, my favorite containers for indoor bulbs are specialized bulb vases. These vases have a large opening that narrows slightly before filling out again, allowing you to place the bulb inside and above the water line. The roots will grow down into the water while the bulb remains mostly dry.
The only problem with these containers is that they typically only fit one bulb at a time. You may need to invest in a couple at a time for a fuller display or stick to planting several in larger pots instead.
Fill your container with high-quality potting soil to retain moisture. If your container doesn’t have much (or any) drainage, plant in a lighter potting mix to prevent rotting.
Each bulb will have slightly different instructions for planting, particularly when it comes to planting depth. Check the instructions on the packaging for steps to get it right. Regarding spacing, you can generally plant in containers slightly closer than in beds outdoors.
The most important thing to remember when planting is to plant the pointed side upwards. If you accidentally plant them upside down, you guarantee they won’t grow successfully.
After planting, managing the environment is key to a long and successful blooming period.
Immediately after planting, keeping the pot in a slightly dim area is best to slowly acclimatize to the new conditions, replicating seasonal changes in their native habitats. Once you spot new green growth (usually within about a week), you can move the container into a brighter area to promote flowering.
Avoid any harsh direct sun as this can cause the flowers that do emerge to wilt quicker. Cool areas with mostly bright indirect light throughout the day are best if you want your flowers to last long. You can also move their containers to a cooler area at night to preserve the blooms.
Regular watering will promote better root growth, delivering even better flowers later on. The soil should remain slightly moist but never soggy, as this can lead to rot. If you’re growing in water alone, monitor the water line so the bulb’s base is always lightly touching the water and the roots are covered.
Bulbs are storage vessels that contain moisture and nutrients. That means they should have all the nutrients they need to flower successfully at planting time without your additional effort. You can take fertilizing off your to-do list, simply enjoying the blooms within three to four weeks.
Once they have finished flowering and start to die back, remove them from their container.
As the forcing process is hard on the plants, it’s highly unlikely that they will flower again the following season. There is, therefore, no need to store them for replanting or put any effort into forcing them again to flower.
The best place for them after flowering is your compost heap. Here, they will continue to be useful, and you won’t have to make space in your indoor garden for plants that won’t flower. If you want to grow indoors again next year, buy new and fresh ones to increase your chances of success.
Impatient gardeners who want to brighten their indoor gardens over winter should try growing potted bulbs indoors. They are wonderful additions to any indoor garden, especially for those who don’t have the outdoor space to grow them.