While rosemary grows better outside than indoors, it can still be grown indoors if the conditions are right, but can it grow so well indoors that it will flower?
I have been growing rosemary both indoors and outside for over a decade, so I have tested this extensively and have an answer for you.
Rosemary growing indoors can flower under the right conditions, although it is more challenging than outside and will rarely be as prolific. Place indoor-growing rosemary in a sunny spot by a window to increase chances of flowering.
The biggest reasons why outdoor-growing rosemary flowers more prolifically than indoor-growing rosemary are environmental factors such as sunlight and pollinators.
I have had my indoor-growing rosemary flower multiple times so I know for a fact that it can happen. In fact, the photos in this article are of my own rosemary plants that I grew indoors.
It might not produce as many flowers as it would outside but I have some easy but effective tips you can use to help your rosemary flower better.
How To Boost Flowering in Rosemary Growing Indoors
It can be difficult to get rosemary to flower when growing it indoors but it is far from impossible. I’ve done it myself many times, so I know what to focus on to get the best results.
The tips I’m about to share here will not only encourage your rosemary to flower but boost the entire flowering process and result in more flowers than otherwise.
To increase the chance for indoor-growing rosemary to flower and increase the amount of flowers, do the following:
- Give your rosemary at least 8 hours of sunlight per day
- Use sandy, well-draining soil with only little organic matter
- Keep temperatures around 70° F (21° C) during the day
- Allow the soil to almost dry out between waterings
- Prune annually and harvest frequently
- Allow the plant to become slightly root bound
This is precisely what I’ve done to make my indoor-growing rosemary flower multiple times. As you can see in the photos in this article, it isn’t quite as prolific as it can be outside but it is definitely something.
If you don’t already have a rosemary plant, get the biggest and most prolific one you can find. Look for one with many stems full of green foliage and if possible, go for a plant with thick stems as that indicates that it is older and more well-established. This can increase the chance of flowering.
If the primary growing conditions such as sunlight, temperature, soil, and watering are as I explained here, your rosemary will most likely flower at some point so patience might be the best next step.
Keep in mind that rosemary usually doesn’t flower in its first year, so if your plant is still young, you might have to wait until next season to see flowers.
Regarding temperature, try to keep it around 70° F (21° C) during the day and slightly colder at night to mimic the natural daily shift in temperatures.
According to the University of Wisconsin-Madison Horticulture Extension, allowing rosemary to become slightly root bound promotes flowering. Just be careful if you try this, because if a plant becomes severely root bound it will die as it can’t obtain the water and nutrients it needs.
I have another article where I go into more detail about how to promote flowering in rosemary, which I recommend reading. In it, I cover all the steps from above thoroughly.
More Tips To Help Your Rosemary Flower Indoors
If you don’t have outdoor space to grow your rosemary, do not worry. It can grow inside next to a sunny window if the conditions are right or on a balcony if you’re lucky enough to have that.
That was the only option I had for several years and during that time, I had rosemary plants flower both on balconies and indoors multiple times.
The tips I shared earlier in this article are the key to keeping your rosemary happy and encouraging it to flower but I have two more tips I want to share as they can dramatically increase the chance that it will flower.
The first tip is mostly relevant if you don’t already have a rosemary plant but the second one can be helpful regardless if you do or still haven’t bought one.
Get the bushiest and most well-established rosemary plant you can find. Look for one with thick stems as they are typically older but make sure it has plenty of foliage too. More stems mean more room for flowers.
Of course, larger and older plants are usually more expensive than smaller, younger ones but they are usually also hardier and more productive. So if you can afford it, I recommend doing that but otherwise just get one you like.
Transplant your rosemary from the pot it comes with to a larger one early in the spring. Rosemary is prone to becoming root bound and the pots used at garden centers and nurseries are usually not very large, so it is often a good idea to repot right away.
Getting your plant started early in the spring gives it as much time as possible to grow and establish itself before next winter. This further improves the chances that it will flower. If you need it, I have another article where I explain how to repot rosemary.
Lastly, I want to mention that IF you have outdoor space to plant your rosemary, consider doing that and putting it in the ground instead of keeping it in a pot. That way, the roots have more room to grow and the plant will be exposed to more sunlight than indoors, which increases the chances that it will flower.
Check out my complete guide to rosemary flowering
If you want to learn more about the flowering process in rosemary, I have written just the article for you. In it, I cover what to do when rosemary is flowering, why flowering is crucial for the survival of the plant, what happens to the plant when it is flowering, what time of the year it usually happens, how to promote flowering and much more. If that sounds interesting to you, check out my complete guide to flowering in rosemary.