21 Tips for Growing Massive Basil Indoors
Perhaps you are thinking of growing basil indoor, excited by the idea of having the freshest and tastiest leaves for your plates. Maybe you already have a few basil plants, but they are tiny, they die quickly, or they are not producing all the leaves you want.
This post has you covered. It provides 21 tips I know and discovered from expert gardeners.
These will allow you to transform your basil in a leaves factory. With a couple of plants, you might have all the leaves you need for you, your family, and friends. Let’s dive-in!
Tip #1: Choose The Right Variety For You
When I talk about Basil with my friends, they always believe I am referring to the Genovese basil, the one used to create tasty pesto. However, there exists a massive variety of basil types. There is no one variety easy to grow than another. However, they do have totally different characteristics, that you need to know them before choosing which basil variety to grow.
For instance, if you would like more a decorative herb you might go for the fascinating purple basil (yes, its leaves are actually deep purple, altought you need to be carefull to the three reasons why it might turn green). In case you do not have lots of space, but you still want your own basil, you can adopt Greek basil.
Perhaps you are looking for an herb with beneficial properties. Then you might need to try the famous Thai basil-based tea, well-known for its antioxidant properties. Your family perhaps might be obsessed with Indian food (like me). In this case lemon basil suits you, a great addition in many curry dishes and deserts.
The bottom line: possibilities are endless. If I was in you will simply look for in Google for the term “basil variety” to find out which basil types do exist and the one you prefer the most. That will be the one you will grow
Tip #2: Start From Transplant, if Available
To start growing basil, you have a few possibilities: from seeds, or transplanting an existing one. In my opinion, transplanting makes life easier. Indeed, if you grow from seeds, after sprout, you have to transplant anyway after the basil reach a specific size (on this point, in later tips).
Moreover, starting from seeds have the “disadvantage” of time. You need to way 1-2 weeks before the seed sprout and another couple of weeks before reaching a size that allows it to be transplanted.
Starting from seed is not wrong (and actually I enjoy it as I can see the plant starts from the very beginning). However, it is more challenging than starting from an already grown and healthy basil. Remember that you also need a seedling soil. A potting soil might need to be sterilized first. Transplanting indeed will increase your chance of success with this herb.
Indeed, seeds might not germinate (soil too cold/warm, not enough light).
Tip #3: If You Can, Plant In Late Spring
One of the most significant advantages of planting indoor is the possibility to control the growing environment of your herbs, right? Yes, to some extent. Indeed, when you are not home, you are not probably (not the majority of you) leaving the AC or heating ON just for your basil. Hence, the temperature might drop, and this can affect significantly the grow of your basil (temperature, as discussed later on, is a key, often forgotten factor, for your basil success).
Moreover, if you are just starting in the fascinating (and tasty!) indoor gardening world, perhaps you do not want to buy a grow light from the start (although grow light are becoming more affordable and easier to use as discussed in this article).
Hence, to avoid disappointment, even if inside, plant at the end of spring. Indeed, your herbs will be ready to flourish for the summer. This is the best season for it due to the abundance of sunlight and warm temperature (if you do not live in an extremely hot area).
If you are reading this in cold winter, no reason to despair. Basil can successfully grow also in winter if indoor. Of course, in such a case, you need to supply light and provide the right temperature that mother nature cannot.
Tip #4: The Container Size Adapted to The Basil
I bet you are not wearing the same pair of shoes your parents bought you when you were 3 years old. This is because you grow up. The same applies to your basil! Indeed, basil, as well as any other plant, do not grow only in height, but also in root extension.
The older it gets, the longer its roots become (within of course a limit). This is a natural mechanism that any plants develop to catch more nutrients, needed to stimulate growth and new leaves to feed.
However, many make the mistakes to ignore this aspect, causing the well-known, among more experienced gardeners, the root ball. As described in one of my previous articles, due to the lack of space, the roots reach the surface of the container. As they cannot go through them, they will start circulating it. This means that there is not enough soil for all the nutrients it needs.
This is a sign of a problem. Indeed, your basil can survive, but definitely, it will not thrive as there is not a physical space from which it can gather the needed nutrients.
Basil, at its full growth (from 6 inches in height and above from the majority of medium/large size basil variety), requires a pot volume of around 2 gallons and a 10-inch depth (more details in a previous article). Of course, gardening is not an exact science.
However, the pot should be deep enough to allow the roots to growth at their fullest (they typically arrive at a length of 8-12 inches depending on the type). In the case of small basil, like the greek variety, a smaller container (especially in diameter) would be fine.
Please, keep in mind that a larger container is not better. Indeed, a larger container implies more soil and, in turn, a large volume of water trapped in it. So, if the basil is not large enough to absorb such amount of water, the soil will always remain wet, potentially causing root rot. This is indeed among the most common causes of basil death among beginner gardeners. To avoid such issue you can always use water crystals.
Tip #5: Go For Clay Containers
You know that size matters. However, on the market, you can find a large variety of materials of which your container is made of. From the classic clay pot to cheap and light plastic ones, to even metals ones. Which one to choose?
Well, the easiest to maintain your basil in good health is definitely clay. Indeed, its thick wall guarantees a constant soil temperature and does not confine water as efficiently (too efficiently) like plastic.
I want you to remember that clay is a choice exclusively driven by what is best for your basil. However, if you have a toddler or a pet at home, a plastic container is a safer choice. Indeed, in case of a fall, it will not break in dozens of sharp-edged pieces that might cause serious harm.
The only case I would avoid clay is for weight issues like in the case you are building a shelf-garden as detailed in this build your own basement garden step by step guide.
Tip #6: Container Must-Have Drainage Holes
This looks like something that hopefully, most of you know. But I will not be tired enough to repeat it. Drainage holes are fundamental to allow the extra water that you might have poured in, to flow away rather than stay stuck in the soil.
Regarding the drainage, I always recommend emptying the plate placed at the bottom of the container (the saucer) to prevent the soil from being always wet. Indeed, at least my basil, thrive when alternating days of moist soil with 1 day of dry soil in between.
Tip #7: Avoid Place Pebbles/Gravel At The Bottom
You might have heard or read that placing pebbles, gravel, or any coarse material at the bottom of your container will improve drainage. This technique is suggested exclusively in case you are building a container without drainage holes (like a fish tank, or a mason jar as discussed in this article or this one). If you have a standard plant container, then, using pebbles at the bottom cause more harm than good.
In simple words (for more, just google “perched water table”) the water tends to go down through the soil and stop until a level defined by the height of the soil within the container. From this level downwards the soil will remain wet (saturated) until water is absorbed by the plant roots.
If you place pebbles at the bottom of the container, the portion of soil that will remain wet (as there is less soil) will be higher. This is terrible news as your basil might than have a more substantial portion of its roots wet for a long time. A very informative video on the matter is below:
Tip #8: Toothpick To Move the Soil
This is something I learned with one of the potting mixes was using. I started, perhaps like many of you, choosing a random potting mix I found in my local Asda (the UK equivalent of Walmart, usually smaller).
Even though my first basil plants growth well, I noticed that the potting mix was quite heavy and the water was actually taking a while before penetrating into the soil. This is generally a sign of poor drainage. Hence, to solve this issue, I just gently move the soil with a toothpick every time I water it.
This guarantees not only the water to reach the deepest layer of the soil where the roots are, but also increase aeration. The only word of warning is to be mindful and avoid touching the roots when moving the soil (you will notice that if you encounter resistance when moving the toothpick).
Moreover, as a further tip, I use the toothpick to move the soil in the drainage hole (just from time to time). Indeed, it is not uncommon that, with time, the soil tends to compact, making it more difficult for the water to come out.
Tip #9: Use Good Quality Potting Mix, Not Gardening Soil
The medium where your basil grows is as important as light and watering. Fill the container of your basil with heavy and nutrient-deprived soil, and your basil will never thrive (actually might struggle even to survive).
Hence, if you are not among those people that love preparing their own potting soil (more on this article), you can choose any good brand potting mix. One of them is the FoxFarm (you can find here in Amazon) or you can check a full analysis in the article below.
Remember that potting mix is not soil and it is absolutely not the same as garden soil. Indeed, garden soil is heavier with a lower drainage and aeration capability. Potting mix, on the other hand, is carefully designed to meet the physical and chemical requirements for a plant living in a pot, a totally different environment.
In general, it is a bad idea to use garden soil for potting herbs. Indeed, your basil might only suffer from lack of air and (lack/excess) water at the root level (in case the garden soil has a high silt/clay content). Moreover, garden soil can also introduce pests in the container, where they can massively multiply and spread like wildfire.
Hence, given the limited cost of potting soil (like the excellent Fox Farm Ocean, here in Amazon) is a no brainer to use it. It will save you time and lots of frustration.
Tip #10: Transplant Only Once Or Never
Basil can easily thrive after a transplant. However, it is always a stressful operation that might quickly kill it if, for some reasons, it was already weak. Hence, as a rule of thumb, I transplant the basil only once during its lifecycle (remember, basil is an annual herb that, at most, will last one year).
If starting from seed, I just wait around 6 weeks (or when I have a 6-inch plant, excluding the greek variety, as smaller) before moving it to its final pot. If I bought a supermarket basil plant, I transplant it (well them) straight away (the sooner, the better) as better detailed in this article.
Transplanting is not always straightforward. Indeed, you need to pay attention to not damaging too many roots (a few of them will be inevitably broken, is normal). Moreover, you need to be sure that the soil is of the right type. Furthermore, to limit the herb stress, I would pinch away some leaves, just to reduce the activity of the plant that can so focus on its roots. More on a previous article.
Tip #11: Water Frequency – There is No Answer, Just Use Your Fingers!
This is a quite common suggestion, to be honest. However, see my friends killing one basil after the other, and reading forums with similar experience, I realized how common this problem is.
If someone gives you a precise frequency by which you should water your basil just tell him that Andrea from indoor herbs disagrees! Indeed, the “frequency” by which your basil should be watered is a combination of a large variety of factors (most of them might be even not known by you) such as:
- The number of daylight hours: the more hours of light, the more water needs as the soil dries quickly due to higher evaporation and accelerated growth.
- Type of soil: a well-aerated potting mix with high retention capability (high content of peat moss, more on the subject here) will need less frequent watering.
- The ratio between basil size and soil volume: a larger plant in a small pot will dry out the potting mix quite quickly. That’s why, if you want to keep your supermarket herb alive in their original containers, you need to water them almost daily;
- Ambient temperature: the warmer the environment, the more water you need to provide. This because a more significant proportion of water will evaporate before being absorbed by the basil;
- Type of container (clay or plastic): basil in a plastic container might require a lower watering frequency due to the water-retention capability of plastic over clay.
That’s why I do not believe in a given watering frequency. It is way easier and reliable to find out such watering frequency with a bit of experience.
Indeed, just water your basil and stick the finger in the soil. Then check if
- Is a bit soil sticking to your finger but not wet? This is the ideal watering level.
- On the other hand, if your finger comes out totally dry with little to none soil on it, then your basil is claiming for water
- Is your finger totally wet? You have overwatered your basil.
Do this a couple of times, and in a week or two, you will figure it out the correct watering frequency. Remember also that, because of the above, the watering frequency will change during the year (reducing in colder season). In this case, I do suggest to just watch out for early signs of stress in your basil.
Wilt leaves are the first red flag to look at. They can be both a sign of over or underwatering. In this case, I would “taste” again the soil to check (just plunge your finger in it) if too wet or dry.
Finally, as a take away I want you to remember that underwatering your basil plant is a way smaller problem than overwatering. Indeed, even if you skip 1-2 days and the leaves start wilting, it is sufficient a good glass of water to bring it back to its splendor. After a few hours, your basil will be happy again.
Tip #12: Your Most Temperature Comfortable
Temperature is an essential factor for basil growth. You might already know that basil does not tolerate low temperatures. Indeed, gardeners usually grow it outside during the summer to then moving it in a container indoors during the winter.
More precisely, basil tolerates temperatures between 45 and 80 F (8 and 27C) as also discussed in by scientific research. However, basil gives its best with a temperature close to the upper limit, ideally 64-77F (18-25C). These are the temperatures at which your living room and any other room in your house are kept! So, no need for any special arrangement for your basil. The place in which are most comfortable will also be ideal for your green friend.
The only note is to avoid keeping your basil close to air conditioner vents, especially if cold air.
Tip #13: Natural And Artificial Light If Needed
This is a hot topic among gardeners with sometimes divergent ideas, although it is not that complex.
Your basil simply needs at least 6 hours of plant-light, ideally 8. As you can notice, I did not use the term “sunlight,” but just plant-light. Here, with plant-light, I mean any type of light (natural or artificial) that allows fully plant development.
During the summer, you do not need any help, as the sunlight from a south-oriented window is more than enough. However, when the days got shorter, you need artificial light if you really want your basil to thrive (or survive depending on where you live).
As discussed in detail in this article, you cannot use a random light bulb you pick in the supermarket as a source of artificial light. Indeed, plants are susceptible to the quality (let’s call it this way) of the light.
An ordinary light bulb will produce very poor-quality light for plants independently on how powerful (Wattage, a measure of the brightness to make it is simple) it is. You need to use the so-called grow light. You can find them for a dozen dollars on Amazon. My best pick is the one discussed in this article. However, you can find an even cheaper option in Amazon.
I do recommend LED grow light. They are slightly more expensive (but still very affordable if you have just a few pots). They last way longer than other technology and they consume way less energy (lower energy bill as you can check in this article).
The only aspect to remember is that many LED lights produce purple light (that your basil loves). So you need to place them in a room where you do not sleep or does not bother you (imagine watching a good movie with blurring purple light on the side, not ideal!).
As a side tip, I suggest using the lamp in coordination with a “timer socket plug.” This is a small box connected between your wall socket and the grow light plug. It is convenient as it will turn ON-OFF your grow light automatically every day without you moving a finger. You can find them for a few bucks in any retailers and you can check their price in Amazon.
Tip #14: Pruning Whole Stems, Not Single Leaves For Massive Growth
If I have to value my tips from 1 to 10, in terms of positive impact on your basil growth, well this one will be 11! Indeed, this is the most important tip and often unknown among those of you that are starting.
You need to know that basil behaves like a real hydra! Indeed, if you prune it (properly), it can grow double the amount of branches! That’s crazy as you can turn your plants in a bush in no time.
The secret is where to cut it. Indeed, the best location is just above a few millimeters (a quarter of an inch) above a node. A node is shown in the picture.
If you cut the plant at that point, you will have 2 branches departing from it. Imagine what would happen if you keep repeating this process? Yes, bushy and luxurious basil. On the other hand, if you just pick the leaf, there will not be any regeneration/multiplication process taking place, leaving you with an emptier plant.
Without getting too nerdy (Wikipedia can definitely help if you are curious) this happens because in the area close to a node there is a particular type of cells that stimulate growth. Interesting enough, these cells are only close to the node! If you cut the stem in the middle between two nodes, nothing will grow!
The only drawback here is that you have to prune even if you do not need basil at that moment! However, this is not a real problem if you read one of my article where I discussed countless of way to preserve basil, here.
Another tip: never cut the wooden part at the very base of your basil. If you do so, your basil will not grow anymore.
Tip #15: Pinch Flowers As Soon They Appear or Before
This is another powerful pruning technique ignored by starters that have the power to make your basil last way longer! You have to know that any plant, basil included, is “designed” by mother nature for reproduction. This happens with flowering. Hence, when your basil starts flowering it has accomplished its final objective and will start to die.
However, here is a trick to extend its lifespan significantly (up to several months): just prevent the basil to flower! As simple as that! How? Prune it regularly and at first sight of flower pinch them off!
The basil indeed, as it did not manage to flower (because of your intervention) will keep growing and producing leaves pushing its limit until what is physically possible!
Of course, do not expect your annual basil to last decades as its limit is still of a year. However, it might happen that it flowers way earlier, so this technique can grant many more months of green and fragrant leaves for your pesto.
Pro tip: in case your basil has already flowered, you still have a small hope to save it by pruning it until the very base above the first couple of true leaves. This is an aggressive pruning and it might (or might not, depending on how much the flowering process advanced) to extend its lifespan. I do recommend to fertilize it (more on the next tips) just a week before such pruning to increase the chance of success.
Tip #16: You Need Fertilizer, Water Is Not Enough
This is something that many forget. Having adequate watering and sunlight is NOT enough. Basil, like many other plants, needs a large variety of other nutrients that is not able to produce itself. Among the most famous, we have nitrogen, potassium, and phosphorus. If these nutrients are not in the soil, then your basil will suffer and eventually die independently from how well you water it and how much light it receives.
If you use a potting soil that does contain already fertilizer (the majority of good potting soil do as the one here discussed) and nutrients your basil will be fine for a few months. However, after 6 months or so, very likely, your potting mix will be depleted of nutrients, and your basil will feel it. Yellow leaves are the first sign of it, a few more symptoms in this article)
However, you do not need to despair and through the potting plant after 6 months. It is sufficient to add fertilizer. Which one? I go for liquid due to its fast action, and it is also more indicated (compared to its pellet counterpart) for potted plants.
However, you need to be cautious as it can burn your basil roots if not correctly (and heavily) diluted in water. In my case, I use one teaspoon for each liter of water (provided every 2 weeks). For more information on the right type of fertilizer here a reading. In general, if you find any fertilizer close to the 10-10-10 ratio (N-P-K, you can see this indication in the label of every fertilizer) or anything close is a good choice.
You can find different type of fertilizer suggestions out there, such as urine or food scraps. I would avoid both for simple reasons. The first one (after the apparent hygiene problem) is too rich in nitrogen. Even if diluted, it will still cause a nutrient imbalance. Coffee ground is a good idea, but only in specified conditions (as detailed in this article) and in moderation.
Food scraps submerged in pot soil? Generally, a bad idea as it will attract any kind of insects (especially in case you use banana peel as many suggest).
Tip #17: Sometimes You Need To Let It Go But Learn The Lesson
During its lifespan, even if indoors, your basil will likely incur some kind of diseases of pest invasion. One of the most common problems, by far, is overwatering. In this case, you will notice your basil leaf wilting and (by tasting the soil with your finger) you will then realize that the soil was too wet.
Most of the time, I do personally do not bother to save root-rot basil. Only in case the plant is well developed and is producing a significant number of leaves I bother. In such an example if you really want to give it a try, what I would do is to extract it from the soil and check for rotten roots (the ones that are brown and slimy).
After removing them, I would let the remaining healthy roots dry for a few hours and transplant the basil in a new pot (or the old pot cleaned with bleach to kill the root-rotting bacteria). However, it will have little chance of survival as already weak due to the root-rotting. Moreover, if you notice during the transplant that the majority of roots are rotten, just do not bother. It is time to replace it.
That’s why I do suggest to have at least 2-3 basil plants located, if possible, in different location of the house. In case one plant is attacked by a disease or pests you have still other plants as a reserve of fresh leaves and far enough to not be affected.
Tip #18: Add a Layer of Mulch On Top
This is a suggestion mainly valid for those leaving in very hot places where summer days can get really hot. In such a case you might have noticed that due to a combination of factors, your basil can get incredibly thirsty. Indeed, the: 1) intense direct sunlight (that accelerate the water evaporation), the high temperature (further evaporation) and the faster pace of growth of your basil (need more water) might force you to water it very frequently to keep it healthy and happy!
However, this is a problem. Indeed, suppose that you go for a weekend trip? In this case, a couple of days can be enough to get your basil in trouble. You can slow down such evaporation (and so the need of frequent watering) by covering the soil with a thin layer of mulch (it is like a blanket).
However, this comes with a downside! In case you overwater, your basil less forgiving for overwatering. Indeed, the soil will stay wet for longer, potentially causing root rot. For the same reason, I do suggest to use such a strategy only during the summer. Indeed, during the winter, if you are not careful, you might be risking overwatering it.
Tip #19: Do Not Harvest Before 6th Leaf
A basil plant, if grown from seeds, it requires a bit of patience. Indeed, before harvesting the first leaves, you might need to wait around 2 months to have suitable basil leaves. This is generally the time required to develop the first 6-8 true leaves. At this time you can start with the first harvest.
This is because a leaf in a basil plant is an energy powerhouse. Leave the basil with to little leaves and it might have an hard time of growing back.
A true leaf is a leaf that presents vessels. Indeed, basil can also have the so-called not-true leaf (or seed leaf, you can see them by googling “Cotyledons”, their scientific name). These are usually two in the basil plant and are the first to develop. They are lighter in color, do not present vessels, and they are way smaller than usual (or true) leaves.
This six/eight leaves rule of thumb among gardeners is to avoid harvesting the basil too early, a situation that can limit its full development potential.
Tip #20: Pinch Bad Looking Leaves
If you want to maximize your basil harvest, you need to avoid wasting its nutrients in activities that will not bring any benefit. This is the case with leaves that you noticed you are not going to eat (brown, wilted) or that have been attacked by some pests.
Indeed, your basil is not able to differentiate a healthy leave from a damaged one in the sense that both receive nutrients, water, and gases for their development. However, as you already know that you are not going to use those leaves, just pinch them off (following, if you can, the suggestion in tip #13). This will allow your basil to distribute nutrients better and boost the development of new (and existing healthy) leaves.
Moreover, a leaf with a problem might spread its disease to others, still healthy, leaves making the situation even worse. This is often the case with fungi-based diseases whose transmission happens just by the migration of very tiny (and very light) spores. This can happen very quickly by a simple breeze of air or splash of water.
Tip #21: Avoid Earthworms In Potted Basil
How many times you might have heard that earthworms are the best plant friends. This is not the case in every situation!
Indeed, it is true that, as everyone claims, earthworms, by moving the soil, increase root aeration (import to boost healthy growth). It is also true that the produced worm manure (yes, worm-poop) is one of the best natural fertilizers. However, before running to a park hunting earthworms for your basil keep reading!
This natural relationship plant-worm did not develop in a day, but in thousands of years of adaptation sharing the same open space environment. Worms are used to have plenty of space to move and reproduce (as there are not, earthworm size boundaries to their world). Indeed, earthworms eat a variety of organic material that they can found both on the soil surface (dead insects, leaves) and within the soil such as bacteria/fungi.
Hence, a small basil pot, on top of a shelf in a room often closed, with no insects around and a “relative” sterile soil (compared to an outdoor garden) offers way fewer nutrients to your worms. This is a problem as, although still, many gardeners might deny it, earthworms can feed on healthy roots in case of food shortage, BBC here. Hence, or you feed them properly (extra effort) or might loos them (and your basil as well).
Even in case you externally provide the right nutrients (that is more demanding than taking care of the basil) you need to control the worm population. Too many worms and you will soon have dead (smelly) ones on your kitchen counter or on your floor. Indeed, when the container gets crowded, worms will start escaping through the drainage holes.
Related Questions
Is basil easy to grow indoor? Yes, basil, with other herbs such as mint (either peppermint or spearmint) and chives, is recommended by many expert gardeners to beginners. This is because it does not require challenging conditions (temperature, watering, soil) to grow.
Can basil be grown in the same with another herb? It depends on the herb. Basil will flourish if placed, with adequate distance, in the same pot with parsley. However, planting basil and sage is not a great idea due to their different water requirements. Indeed, this set-up will make impossible to water both of them at the same in an adequate manner.
Further Readings
Article on earthworms on potted herb
Article on Coffee Ground as fertilizer
Article on transplant Supermarket herbs
Article on the best container size for your basil
Article on how to create the best potting soil
