There are several potential reasons why the leaves on a basil plant sometimes don’t get very large. Certain basil varieties just don’t grow very large leaves, but it can also happen because of an issue you have to take care of. In this post, I cover why it happens and the steps you can take to fix them.
The most common cause for small leaves on basil plants is the lack of sunlight. Other common causes include lack of water and nutrients and too little growing space. Certain basil varieties only grow tiny leaves, but with most basil varieties, it is a sign that there is an issue.
Below, I help you identify if the leaves on your basil plant are small because of an issue and explain precisely how to fix it.
Why Your Basil’s Leaves are Small and What to Do
I have been growing a lot of basil over the years and encountered many different issues in the process.
One of the issues I have had with basil was that the leaves stayed tiny rather than growing to their full size, so when that happened, I set out on a mission to figure out why to get the most out of my basil plants. I have written this post to share what I learned so you can avoid the same issues.
If your plant has stopped growing entirely, I recommend that you read the article on this link instead of this one, since that can happen for different reasons than the leaves not getting big.
I learned that the most important thing when growing basil by far is to give your plant the best possible growing conditions. Poor conditions can lead to many problems including stunted leaf growth.
To give you the most straightforward overview of the best growing conditions for basil, I have made this table:
| Sunlight | 6-8 hours of direct sunlight per day. |
| Temperature | Ideally, 80-90° F (27-32° C). No less than 50° F (10° C). |
| Watering | Small doses every day whenever the topsoil is dry. Water from the bottom. |
| Fertilizer | Once every 2-3 weeks. |
| Pruning | Cut stems just above the third set of leaves and remove flowers as soon as they appear. |
When basil is getting the right amount of sunlight and water, the leaves will grow large so that they can absorb as much sunlight as possible, but the larger the leaves grow, and the more there are, the more water the plant will need to keep the plant and the leaves healthy and growing.
Besides sunlight and watering, temperature, fertilizing, and pruning plays significant roles in how well your basil will grow and how well the leaves will develop.
It is important to note that small basil leaves are not always the result of poor growing conditions. Certain varieties only ever develop tiny leaves. I get back to this at the end of this post, but if you want to grow a basil variety where you can be almost certain it will develop large leaves, I recommend reading this post to find one you like.
While the information from the table above provides an excellent baseline for properly caring for basil plants, the requirements change throughout the season, so there is a bit more to it that you should know about to make your basil plant grow larger leaves. Don’t worry though, because I describe everything you need to know throughout this post.
The conditions from the table above can all play a role in why your basil’s leaves are not getting big, so keep reading as I will describe how to optimize these conditions for better leaf growth.
Below, I dive into each of the different causes for why basil leaves are not getting big and describe precisely what you should do in each situation. Under each headline, you will find a short and precise action step followed by a more in-depth explanation.
Common Cause #1: Lack of Sunlight
Action step:
Provide basil with 6-8 hours of direct sunlight for optimal leaf growth.
Sunlight is one of the essential requirements for basil to grow. Too little sunlight can inhibit the growth of the entire plant, including the leaves, but too much sunlight can cause the plant to take damage or even die.
Lack of sunlight is the most common reason why basil leaves are not getting big. Basil plants absorb sunlight through the leaves and adjust their leaf growth and production to match the amount of sunlight available. Therefore, if there is not much sunlight, basil’s leaves will stay small.
So to make your basil plant grow and produce larger leaves, you must make sure it is getting enough sunlight.
Basil needs 6-8 hours of direct sunlight to thrive. Less than that will inhibit the growth and production significantly.
If you live in an area that does not get enough sunlight for basil to thrive or it is not the right season, you can still grow basil indoors, although you will need some grow lights to provide the plants with enough energy to grow.
No matter how good the conditions are when it comes to sunlight, your basil will not grow larger leaves unless you also know how to water and fertilize it correctly. I get into this now.
Common Cause #2: Lack of Water and Nutrients
Action step:
Water basil in small doses every day for bigger leaves. Water from the bottom whenever the top of the soil is dry.
Add liquid fertilizer to the water once every 2-3 weeks.
Basil grows best in soil that is moist but not wet and the soil should never be allowed to dry out completely.
Basil plants consist of close to 92% water, so naturally, they will not grow well without being watered enough, and that goes for the leaves too.
The most common watering-related cause for small basil leaves is underwatering. Basil leaves consist primarily of water, so to grow large, the plant needs to be watered well since the water absorbed by the plants’ roots will be used to develop new and large leaves.
It is always best to water basil from the bottom. This is because it will force the roots to stretch and grow to reach the water, and the larger the root system grows, the more efficiently the plant can obtain water and nutrients. You can read more about that on this link.
Rather than watering basil plants in large doses at a time, it is much better to water it in smaller doses but more frequently. This is because basil thrives best in consistently moist soil. Soil that is too wet will suffocate the roots, and staying in dry soil for too long will kill the plant.
Be careful when you water basil as too much water can result in overwatering, eventually leading to root rot which kills the plant.
Luckily, it is relatively easy to tell if a basil plant has been overwatered. You can read everything you need to know about it on this link including how to save it, but I will also include the essential information below.
Proper watering is crucial to growing large basil leaves. Luckily, it is relatively easy to tell when your basil plant needs more water. I get into this now.
Tips to easily tell if basil needs more water
These are the easiest and most reliable ways to see if your basil needs more water.
Basil watering tip #1:
Touch the top of the soil. If the top inch or so feels dry, you can safely water your basil plant.
Basil watering tip #2:
If the leaves on your basil plant are soft and loose, it can be a sign that it needs more water.
Basil watering tip #3:
As you basil plant grows, it will need more water, so increase the amount of water you give it gradually as it grows while still following tip #1 and #2.
Tips for providing basil with the right amount of nutrients
Other than watering, proper fertilizing will lead to much better and healthier plants with much larger leaves.
Basil fertilizing tip #1:
Use compost to fertilize basil growing directly in the ground. Use liquid fertilizer for basil growing in containers. Add it to the water used for watering once every 2-3 weeks.
Basil fertilizing tip #2:
Use NPK-based fertilizer with a ratio of 10-10-10 for basil. NPK fertilizer contains nitrogen (N), phosphorus (P), and potassium (K) which are three crucial components for basil to grow well.
Basil fertilizing tip #3:
Keep an eye out for discolored leaves, as this can be an indication of overfertilizing. If you see this, do not fertilize the plant for about a month.
The most severe damage from overfertilizing occurs underground on the roots, but keeping these tips in mind will help you know how to fertilize basil properly.
Other than sunlight, watering, and fertilizing, a common reason why basil leaves are not getting big is that the plant doesn’t have enough room to grow. I get into this now.
Common Cause #3: Too Little Growing Space
Action step:
Grow basil in clusters of 3-5 plants with 12-16 inches (30-40 cm) of spacing between each cluster.
If you are growing basil in a pot, use a pot that is at least 12 inches (30 cm) in diameter and place 3-5 plants per pot.
Basil can be grown both indoors or outdoors and both directly in the ground or in a pot or container.
Regardless of where your basil plant is growing, it needs plenty of space for the root system to grow and develop, as this plays a crucial role in how large the plant and the leaves will become.
As a general rule, basil should grow in groups of 3-5 plants. Grow basil in containers at least 12 inches (30 cm) in diameter or directly in the ground with at least 12 inches of spacing between each group. This allows the root system to grow big, which improves the growth of the plants and leaves.
If basil plants are grown in too small pots or too close to each other, the plants will quickly become root bound, which means that the roots have taken up all the space they had. When this happens, the roots will no longer be able to grow, and without a thriving root system, basil plants cannot obtain water and nutrients efficiently from the soil.
The leaves on rootbound basil plants are often underdeveloped since the plant cannot obtain water and nutrients well enough.
Some Basil Varieties Only Grow Tiny Leaves
It is important to remember that small basil leaves are not always the result of a problem.
If the leaves on your basil plant are small, it can simply be because of the variety of basil. Certain varieties only ever develop very small leaves no matter how well you take care of them. For these plants, simply take care of them according to what I have already described in this post, and they will be happy and healthy.
Here are some examples of basil varieties that grow tiny leaves:
| Basil variety | Leaf size |
| Minette basil | 1/4-1/2 inches (1-2.5 centimeters) |
| Greek Basil (Spicy globe) | 1/2-1 inches (1-2.5 centimeters) |
| Boxwood basil | 1/2-1 inches (1-2.5 centimeters) |
| Pistou basil | 1/2-1 inch (1-2.5 centimeters) |
| Summerlong basil | 1-2 inches (2.5-5 centimeters) |
If you are interested in this, I recommend heading over to this post, where I cover 9 of the smallest basil plants with the smallest leaves.
Young Basil Leaves are Smaller than Mature Leaves
One last thing that is important to know is that young basil plants rarely have large leaves.
So if your basil plant is still young and only has a few sets of leaves, it is much too early to worry. Just give it some time while taking good care of it by following the instructions from this post and it will surely grow well and develop large leaves.
In Conclusion
To round this post up, here is a brief resume of what you should do so your basil plant will grow big leaves.
- Pick a basil variety that grows large leaves.
- Give your basil 6-8 hours of sunlight per day.
- Water your basil in small doses every day.
- Water your basil from the bottom.
- Fertilize your basil every 2-3 weeks.
- Grow your basil in 12 inch pots or larger.
- Grow basil 12-16 inches apart in the ground.
Read My Complete Guide to Growing and Caring for Basil
I have written a thorough guide where I cover all parts of growing your own basil including choosing a variety, sowing the seeds, the best growing conditions, pruning, propagation, harvesting, storing, solving various problems, and a lot more. You can find the article on this link.