Transplanting or repotting your rosemary can be an important or even necessary thing to do but it is also a delicate process where several things can go wrong.
As you will see in this article, I have made mistakes when transplanting rosemary before but I have also learned from those mistakes and done it successfully many times since then.
I wrote this article so you can learn from my mistakes and hopefully avoid them so that you can successfully transplant or repot your rosemary.
Mistake #1: Picking a Pot of the Wrong Size or Material
It might not seem like it makes a big difference at first and it might not, but transplanting or repotting your rosemary into the wrong type of pot will almost certainly cause problems eventually.
The most important things to keep in mind when picking a pot for rosemary are the size and material of the pot and that it should have one or more drainage holes.
The best pot for rosemary is made from terra cotta or another type of unglazed clay and is about 12 inches (30 cm) or more in width and depth.
You might not have to go straight to a 12-inch pot if your rosemary is still small, but make sure you transplant it into a pot that is larger than its current (unless it is already large) to avoid having to repot it again too soon.
Pots made from plastic are popular and cheap and can definitely also work, but no moisture can escape through the sides, which it can with terra cotta, which means a higher risk of moisture-related problems. If you repot your rosemary into a plastic pot, make sure it has drainage holes.
I always use and recommend terra cotta pots for rosemary. They just seem to work better than anything else I have tried.
If you need help with repotting your rosemary, I have a step-by-step guide where I explain how to repot rosemary including all relevant information about it.
Mistake #2: Transplanting Too Early or Late
If you transplant your rosemary when it is too small or when it has outgrown its current pot, you risk running into some problems.
Rosemary seedlings should be at least about 3-6 inches (7.5-15 cm) tall before you transplant them.
Like most seedlings, rosemary seedlings are relatively delicate so if you transplant them too early, they might die before they can adapt to their new environment. That’s why you have to wait until they reach those 3-6 inches or more in height.
If you want to learn more about how to tell if rosemary seedlings are ready to be transplanted, head over to my article about that.
If, on the other hand, you wait too long and transplant your rosemary too late, the roots might have outgrown their current pot and ended up looking like these.
If your rosemary’s roots look like the ones in my photo above, your plant has become root bound, which prevents it from obtaining water and nutrients as efficiently as it should, ultimately causing the plant to die.
The only certain way to tell if your rosemary is root bound is to carefully lift it out of its pot. Be gentle though, as the roots can be delicate.
If your rosemary has become root bound, you should gently loosen the roots before you transplant it into a larger pot. I have another article where you can learn more about how to tell if your rosemary is root bound and what to do.
Mistake #3: Forgetting to Harden off the Plant
To harden off a plant means to help it get used to a new environment. It is usually necessary when transplanting a rosemary that has been growing inside to a new spot outside.
If you don’t harden off your rosemary before you put it outside, there is a high risk it will die quickly.
The easiest way I have found to harden off rosemary is to put it outside for about 2 hours in the morning on the first day and then bring it back inside. Turn it up gradually by leaving it outside for 1-2 more hours per day over the course of about two weeks.
Make sure your plant stays inside at night and during the sunniest and warmest hours of the day for the first week or so.
After about two weeks of gradually increasing the outside time your rosemary gets, it should be ready to stay outside permanently. After another week or so, it can be transplanted into the ground if you would like that.
The importance of hardening off your rosemary depends largely on the time of the year you want to put it outside. I have another article where I go into more detail about the best time to put rosemary outside.
Mistake #4: Not Looking at the Weather Forecast
If it rains for a week straight after your transplant your rosemary outside, it will likely not do well and possibly even die within that week.
A small but very relevant anecdote since exactly that happened to me a few years ago.
I put the rosemary in this photo in the ground on a day with gray weather without thinking much about that. What I didn’t keep in mind, though, was to look at the weather forecast. It stayed gray and cloudy for over a week and by the time we got sunshine, the plant was dead.
It is crucial that your rosemary gets some sunlight after being transplanted, although you should be careful not to give it too much if it is used to lower amounts, for example, if it has been growing inside.
Not looking at the weather forecast is an easy mistake to make but it can also result in your plant dying if you’re unlucky. I have another article where I explain more about this and other reasons rosemary might die after being transplanted.
Mistake #5: Using the Wrong Type of Soil
If you use soil that is too high in nutrients, for example, soil that contains a lot of manure or other organic material, the plant can actually die.
Soil like that is excellent for many other herbs but rosemary can easily become scorched or get fertilizer burn if it grows in too nutrient-rich soil.
Instead, you should mix about 30-40% sand into a potting mix or use a succulent or cactus soil mix.
Adding sand to the soil also improves drainage which reduces the risk of moisture-related problems such as root rot. I made the mistake of planting rosemary in soil with too much clay and too little sand before and it can kill the plant quickly.
Mistake #6: Planting at the Wrong Depth
An easy mistake to make when transplanting rosemary is to plant it at the wrong depth.
If you plant it too shallow, the plant will become unstable and if you plant it too deep, soil and moisture will gather around the base of the plant which can cause the stem to rot.
When you transplant rosemary, make sure that the surface of the soil and the base of the plant are at the same level as they were before.
Mistake #7: Transplanting Plants That Are Sick or Have Pests
Before you transplant your rosemary, you should make sure it is free from pests and diseases. Otherwise, you risk spreading these to other nearby plants.
Not all pests are visible since many of them stay under the ground. One way you can tell that something is wrong is if the leaves start to get pale spots or turn brown.
That is what happened to my small rosemary seedling in the photo above.
It is usually not too difficult to tell if a plant is infected since you will either be able to see small insects or visible damage to the foliage. If your rosemary looks like mine in the photo above, make sure you get rid of the pests before you transplant it.
Mistake #8: Picking the Wrong Spot for Your Plant
The most important thing to keep in mind when choosing a spot to transplant your rosemary to is the sunlight. If the spot you pick doesn’t receive at least about 8 hours of sunlight during an average summer day, your rosemary is going to struggle.
Another thing you also need to consider is the soil at that spot. It should be sandy and not contain too much clay or organic material.
I explain more about this and everything else you need to know to put rosemary in the ground in another article.
The last thing I should mention about picking the right spot is that you should consider how large the plant will be when it is fully grown. Make sure there is enough space so that air can flow freely around the plant even when it is fully grown.
Mistake #9: Transplanting at the Wrong Time of the Year
The best time of the year to transplant rosemary is in the spring but the fall can also work. That is because there will be enough sunlight for the plant to establish itself but not so much that it gets scorched, which can happen if it has stayed inside and isn’t used to high amounts of sunlight.
That is unless you transplant it inside for the winter. In that case, you should do it in the late fall or early winter but before there is any frost.
If you transplant rosemary in the winter when it is too cold outside, there is a high risk that it will die before it can adapt to the new environment. You should not transplant it if there is frost as that will likely kill it. I go into more detail about transplanting rosemary in cold months in another article.
You can also transplant rosemary outside in the summer, although you should harden it off as I explained earlier in this article to allow it to get used to the transition of going from inside to outside.
I have another article where I cover everything about the best time to transplant rosemary.
Mistake #10: Overwatering or Overfertilizing
A very common mistake people make is to overwater or over fertilize their rosemary after transplanting it.
Regarding fertilizer, I actually recommend that you don’t use any at all. That is what I have had the most success with.
It can be beneficial to use some fertilizer for a lot of herbs but rosemary can easily become over fertilized, which is also why you shouldn’t use too nutrient-rich soil, as I explained earlier in this article.
Using too rich soil or too much fertilizer can lead to fertilizer burn, which will cause the foliage to look scorched. That is precisely what happened to my plant in this photo.
When it comes to watering, you should definitely give your newly transplanted rosemary some, but be careful. It is very easy to overwater rosemary and when that happens, the roots can rot which will eventually kill the plant if the problem is not taken care of.
To avoid overwatering your rosemary, make sure you allow the top inch (2.5 cm) or so of the soil to dry out before you add more water.
Overwatering, whether after transplanting or not, is by far the problem I have seen and been asked about most often by friends and family who were growing rosemary.
Mistake #11: Forgetting to water
While it is not unique to rosemary, a common mistake I have seen people make when transplanting plants before is that they forget to water them afterward.
You should water your rosemary after transplanting or repotting. If you forget to do that, the roots can struggle to establish themselves, which causes the entire plant to struggle.
That said, you have to remember that rosemary is relatively easy to overwater since it doesn’t need nearly as much water as many other plants.
So make sure you give your rosemary some water after you transplant it, but allow the top of the soil to dry out before you give it more to avoid watering-related issues such as root rot.
Mistake #12: Transplanting too often
While transplanting or repotting can be great tools for helping your rosemary thrive, it can also be done too often.
Transplanting too often will stress the roots, preventing the plant from ever getting properly settled in a new spot. That’s why you should try not to transplant your rosemary too often.
I have written another article where I explain how you can know how often your specific rosemary should be repotted. The article is about repotting specifically and not transplanting into the ground, but if that seems relevant to you, I recommend taking a look at it.