How to Keep a Basil Plant Alive and Thriving (Indoors and Out)

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Basil is one of the most popular aromatics in the world. People from all over the globe use the herb to flavor their dishes and give them a sweet, slightly spicy aftertaste. 

Although, we all know that when you buy fresh basil from the store, it’ll only last a few days. That means you may have to take a trip to the grocery store a few times a week. 

Well, if you’d rather skip the hassle, but still want to use basil to add a zing to your dishes, there’s a simple solution.

Luckily, you can grow these plants at home, both indoors and outdoors. So, if that sounds interesting, you’ve come to the right place. 

In this article, I’ll walk you through everything you need to know about how to keep a basil plant alive and thriving. 

Basil Plant Lifespan Overview

Before we start talking about the lifespan of basil, you’ll need to get your hands on a plant. Thankfully, this is exceptionally simple. 

You can pick up basil plants at the store or even online. However, if you’re buying the flora off the shelves, there are a few considerations you need to keep in mind. 

For starters, store-bought potted basil usually has 10 to 20 plants crowded into one pot. It makes the plant look lush, giving you the allure that you’re getting loads of fresh produce with a cheap price tag.

That you are, but you’re going to have a hard time using it before the plant starts wilting. After a couple of weeks, the leaves begin yellowing and ultimately, the basil plant starts withering away to nothing.

This is a longer shelf life than pre-packaged fresh basil that usually lasts just 5 days, but it’s still not that much time. 

Truth is, the potted basil plants that are sold in stores are intended to have a short lifespan. They’re consumer plants meant for cooking.

It’s not like you’re buying basil from a gardening nursery that’s grown from seed, fed the right nutrients at the right intervals, and grown under specific lighting conditions.

So, figuring out how to keep a basil plant alive may prove trickier than you likely imagined.

Store-bought herbs are for using, not planting, yet that’s exactly what you need to do if you’re to have any chance of learning how to keep basil plants alive for longer.

Give any half-decent basil plant a good start in your home, either in the kitchen or your garden and you can significantly increase the life of it and the amount of basil you can harvest from it.

Indoors, any healthy basil plant can get you around two months of fresh basil, possibly longer.

5 Common Causes of Basil Plants Dying

Understanding the lifespan of basil plants is only one part of keeping the flora alive. It’s also crucial that you figure out the common causes that are leading your plants to fade away. 

In this section, I’ll cover some of the most notable culprits behind your basil wilting. 

1 – Too Much or Too Little Watering

1. Too Much or Too Little Watering

By far, the most frequent killer of basil plants is inadequate watering. There’s never going to be a schedule you can use to water these as they only drink what they need.

For that reason, it’s best to err on the side of caution and give the plants less water than you think they need. It’s easier to add water to a thirsty plant than it is to help a drowned plant recover. 

Besides that, another common cause of a basil plant wilting is root rot, and that’s caused by too much water.

Over-watering can also be a result of the soil not draining as fast as it should. So, before adding water, use the finger test on your soil and only top it up when the top inch of soil is dry to the touch.

If it’s still moist, leave it until it dries.

2. Temperatures Dropping Too Low

Basil plants love their heat. The ideal growing temperatures are between 80℉ and 90℉ (27℃ to 32℃) in the daytime and are no lower than 55℉ overnight. 

Plus, they can’t tolerate temperatures much lower than 50℉ (10℃). As a result, garden-grown basil will need to be brought indoors in the winter months, or overwintered in a greenhouse.

Even if the low temperatures don’t cause your plant to fade away, it’ll likely lead to browning on the leaves. That’s why you should store fresh basil at room temperature and never in your fridge.

3. Insufficient Lighting

As basil is a sun-loving plant, it needs a lot of light. Ideally, the flora should have at least four hours of full sun daily. 

Depending on where you live, a sunny windowsill may be the perfect solution. But that’s not the case if you’re in northern areas.

You’ll likely need to supplement sunlight with artificial lighting or grow your herbs using grow lights without relying on sunlight at all.

4. Overcrowding

If you’re growing your basil outdoors, perhaps in a raised garden bed, they need at least 12 inches of space between them. Otherwise, the plants will compete for the nutrients in the soil. 

Unfortunately, there’ll be no winner. 

Overcrowding isn’t exclusive to basil plants nearby. Any plants, including weeds, can deplete nutrients from the soil. 

So, when you’re tending to an herb garden, you need to pay as much attention to what’s growing around your herbs, rather than just the plants you’re growing.

5. Pests and Diseases

Aside from the growing conditions, there are a few pests and diseases that can cause your basil plants to fade away. Here’s a quick look at some of the most dangerous organisms that pose a threat to your herbs. 

6. Fungus Gnats

Some gardeners use basil for pest control because the strong aroma can have a repellent effect. Yet, fungus gnats are the exception since they’re attracted to the moisture in the soil rather than the foliage on the plant.

Wet potting mix is the ideal environment for fungus gnats to lay their eggs. This ties back to over-watering basil, and it’s another reason you want to let the soil dry out between watering.

7. Japanese Beetles

The Japanese Beetle is about ½-inch in size, has copper wings, and can fly. Unlike fungus gnats that are looking for wet soil to lay eggs, these critters like to snack on the foliage.

They’re fond of basil and are a common pest in outdoor herb gardens. Fortunately, these insects are easy enough to spot and you can remove them by hand. 

Although, if you find yourself up against an infestation, it’s best to treat your herbs with insecticidal soap or neem oil.

8. Grasshoppers

Grasshoppers—in particular, younger grasshoppers that haven’t yet developed wings will linger wherever there’s a food source. That means they’ll hang around your basil plants, snacking on the leaves. 

Thankfully, neem oil sprays and garlic sprays can act as repellents. But, if you’re up against more than a few grasshoppers, the best course of action is to use a floating row cover to cut off access while still maintaining sufficient light and air circulation for new growth.

9. Whiteflies and Aphids

Aphids and whiteflies, although different insects, both have teeth that they use to suck the sap out of the leaves of basil plants and similar herbs. They also lay eggs that feed on the nectar of plant leaves.

That means they’ll wreak havoc on your garden bed. 

To get rid of the eggs and larvae, rinsing your plants or hosing them (gently) should do the trick. Any whiteflies and aphids around the plant will be evident when they’re sprayed as they’ll fly off in a swarm.

Besides that, to control winged insect populations, a popular option that doesn’t include chemicals is yellow sticky traps. That’s because a lot of winged insects, including whiteflies and aphids, are attracted to the color yellow.

You can buy these traps or make your own. All you have to do is coat a yellow piece of card with a sticky substance such as petroleum jelly or something similar. This will trap the flies when they land on the card.

10. Caterpillars

Caterpillars are another pest that can attack your basil plants and cause them to fade away. The critters will feed on the leaves.

In severe cases or with large infestations, the insects can deplete your plants of all their nutrients.

Luckily, since most caterpillars are about two to three inches long, they’re easy to spot. That means you can pick these critters off your plants easily. 

Aside from that, the only approved chemical you can use to control caterpillar infestations is Bacillus thuringiensis kurstaki (Btk). 

11. Slugs

Slugs are garden pests that love to eat your herbs. You certainly don’t want these pesky critters leaving their slimy trail over your basil.

The problem with slugs is they’re only active at night, so you’re less likely to see them. Usually, you’ll only notice the damage they leave on your plant, which will always be the lower leaves and not further up the plant.

As luck would have it, there are many ways to get rid of slugs safely. 

How to Make Sure Your Basil Plants Live for As Long as Possible

Now that you know how long basil plants can survive, it’s time to move on to how to keep them around for longer periods. 

In this section, I’ll cover a few strategies you can rely on to ensure your plants last for as long as possible. 

1. Give Your Basil Plants More Space

The first thing you should do with a potted basil plant is to divide it. As I mentioned, in almost all cases, the pot it comes in is far too overcrowded. 

That’s intentional because the more seeds there are in the pot, the bushier the plant is.

Because of that, space is the first aspect you need to examine. For basil, it grows best in 4-inch containers with no more than 3 plants per pot. 

Since your average store-bought basil has as many as 20 plants in one pot, you can divide it into half a dozen plants and they’ll do better once you give them the space they need to thrive.

How to Divide a Basil Plant

Dividing a basil plant is about splitting the roots with minimal harm to the flora. Sadly, it’s inevitable that there’ll be some damage, so the trick is to do it delicately and carefully. 

Start by taking the pot in one hand and gently loosening the soil. As you do that, avoid handling the leaves and stems, as these are extremely brittle and may snap.

Once you have the root network out of the pot, inspect the structures. Healthy roots on a basil plant should be white, not brown, and stiff to the touch.

Discolored, or soft, roots are a sign of over-watering, which for a new plant usually means the soil isn’t fit for the purpose as it’s not draining as it should. 

In that case, you’ll need to discard the parts of the plant with brown roots and keep the ones with healthy (white) roots.

Then, repot them in 4-inch plastic containers that have drainage holes and use a well-draining potting mix.

2. Replace the Soil That Comes With Store-Bought Basil Plants

Pre-potted basil plants rarely use soil that’s going to last a while. There’ll be enough nutrients in the growing medium to last a week or two (the intended lifespan), but not much longer. 

Trying to figure out how to keep your basil plants alive starts with having the right nutrients in the soil.

Basil, like most herbs, grows best in a growing medium that drains well and isn’t too acidic or alkaline. A pH of 6.0 to 7.0 is ideal. 

So, if you’re planting your herbs outdoors, it’s a good idea to use a soil tester to see what you’re working with and adjust the soil to suit your plants.

Yet, for planting basil in your garden, you can improve the quality of your garden soil by adding either blood meal or cottonseed meal, both of which increase the nitrogen content and help improve drainage in sandy and compact garden soil.

Finally, when growing in containers, you only need your soil to be well-draining and the plant pot to have drainage holes. This should prevent the roots of the plants from sitting in standing water.

3. Use an Insect Repellent

To ensure that pests stay away from your basil plants, you can spray the leaves with a bug repellent. There are many home remedies that can do the trick. 

This includes using vinegar, dish soap, or oak leaf water. All of these agents will give off a pungent aroma that can keep critters away. 

To Pinch or Not to Pinch Basil Plants Back?

Pinching is a type of pruning that involves a gardener removing the top of the main stem of a plant to encourage denser, bushier foliage. 

This practice is terrific for those growing basil for cooking. That’s because, for cooking, it’s the leaves you want and you cannot let it flower. 

In fact, you’ll need to remove flower buds as soon as they develop, otherwise the leaves take on a bitter taste.

To keep your basil leaves producing an abundance of flavor, regular pinching is what’s needed, starting from when the plant is just 6 inches tall.

At that point, the first pruning is best to be the “central stem” since that’s going to encourage new stems to branch out. As a general rule, the more stems you have, the more room there is for denser leaves to grow.

Luckily, all you have to do is cut back the main stem by half its size. 

Moving on, when you’re pinching basil plants back, it’s fine to go heavy on the pruning because they are super-fast growers. You can pinch them back to just the two baby leaves at the base of the stem and still grow enough for a fresh harvest in as little as two weeks.

Plus, given how delicate the leaves are, you don’t need pruning shears to pinch them back. Just use your thumb and forefinger and give the leaves a gentle tug to remove them. The more you pinch it back, the more leaves the plant produces.

However, for those who prefer to grow varieties of basil for the pungent aromas, or colorful flowers that attract beneficial insects such as butterflies and bees, pinching the plant back may delay flowering.

So, depending on how you plan to use your basil plants, your pruning strategy will change. 

Final Thoughts

The most important tip about how to keep a basil plant alive is to divide it into as many smaller plants as you can. The more space there is for the roots to absorb nutrients from the soil, the more basil leaves your plant will produce.

In containers, limit the number of plants to just three per pot. As for garden beds, always space each plant at least 12 inches apart to prevent neighboring plants and weeds from soaking up too much of the nutrients that should be going to your basil plant.

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