How to successfully grow basil indoors in containers, yes even in the winter.
Grow basil indoors year-round!
An indoor herb garden is one of the best things you can do for yourself if you love to cook. Growing your own culinary herbs is really easy and can be inexpensive as well. It's a fantastic way to incorporate more fresh herbs into your cooking as you will always have a supply at hand.
When you grow basil indoors (and other culinary herbs) it is also one way to reduce or eliminate food and plastic waste in your home. Indoor gardening year-round can be a great step towards sustainability in your kitchen, which I talk about in more detail in my article:
The Biggest Indoor Gardening Myth
Let us address this right off the bat — you cannot successfully grow culinary herbs (or lettuce or anything really) year-round by sticking some pots on a windowsill, even a south-facing windowsill.
It will be impossible to grow enough herbs without the assistance of LED plant grow-lights.
There are many articles out there telling you that your south-facing windowsill is all you need and this is honestly just misinformation at best and flat out lying at worse.
I've tried this method several times and it's a nonstarter. Don't waste your time.
There is just not enough light during the cold months to grow a successful indoor herb garden. The most you might get out of a basil plant during a typically cold Canadian January is a leaf or two. Not enough to actually do anything of use in the kitchen except take up needless space.
And this guide for indoor gardening is meant for people who really want to grow herbs to use on a regular basis in their cooking — people like me.
3 Different Ways To Grow Basil Indoors
To grow basil indoors is simple really, as this fast-growing and prolific annual will germinate in as soon as four days (up to two weeks is normal) and grow the first set of true leaves within two weeks.
In the space of four to five weeks, you might be harvesting your first basil. Here is how to grow basil from seed.
Figure out what you will start your seeds in.
I recommend using an old cardboard egg carton, plastic tubs or trays/inserts you have laying around in your home or recycling bin, or buying coconut coir seed starter trays. I minimize plastic as much as possible, but this is a personal choice. Plastic trays are reusable which works in their favour — but so are the egg carton and coconut coir trays if careful with them.
Eggshells are also great (and reusable) for starting seeds as you can easily pop out the seedling for transplanting when it has outgrown the shell.
Get your soil potting mix ready.
There is special seed starter medium you can buy. You can also go straight to buying a good quality organic soil that will have everything you need to get started. Or, if you are ambitious, you can mix up your own nutritious potting soil and I will give instructions for that later on in this article.
To get the soil ready, it needs to be quite moist. Mix water into the soil until it can be formed into damp balls in your hands. And yes, I recommend using your hands, you will get a real feel for how the soil should be. Just keep adding a little water at a time.
Place the soil into your seedling starter tray or trays.
Plant the basil seeds.
Plant the basil seeds by sprinkling them over the soil.
If using small-celled trays, plant 2-3 sees per cell because there are usually a few seeds that do not germinate and this will ensure you are successful.
Cover the seeds with a sprinkling of dry soil and then mist the soil with water from a spray bottle.
Keep the soil moist.
The soil must be moist until germination. Germination will happen quicker under optimal conditions so this is quite important.
There are several ways to do this.
The first is to simply mist the soil and seedling daily from your spray bottle. I do this. If you have a lot of seedlings you're starting, this may be time-consuming.
The second way is to cover the seedling trays with a dome or even plastic cling wrap. Doing this will keep the moisture in and you won't even have to water the basil seeds again until they sprout.
Some seedling trays come with domes for just this purpose. Figure out what you like for yourself.
Place your seeds in a warm location.
Another reason why a windowsill in January is not great. Your seedlings need warmth, for basil, it's approximately 20° Celsius (70° Fahrenheit).
You can also seedling germination mats but this is not really necessary for most herbs, I only have one for peppers and tomatoes.
Watch for sprouts.
Once you see a sprout, even if it is only one sprout, remove the dome or plastic wrap and start supplementing light to your plant. Outside of the summer months, this will come in the form of LED plant grow lights (more on that further on, it is honestly really easy and affordable).
Failure to do this will likely result in leggy sprouts.
Water regularly and consistently and provide adequate air circulation.
When the top of your soil starts to look dry, it is time to water your little basil sprouts.
Do not let the soil dry out completely. I give it a light misting daily from a spray bottle which keeps everything good.
As for air circulation, a small fan turned on for a couple of hours or growing near a window that can be cracked open should suffice. However, neither of these things is absolutely necessary.
If you start to see mould in your trays, you may be over-watering or not providing enough air circulation. Start watering your basil from the bottom up by putting the trays in plates of water and introducing a fan. In my personal experience, mould is a rare occurrence.
Thin out basil seedlings and transplant.
If your seedlings are in small cells and you have had successful germination for most of your seeds, the seedlings in each cell will start to crowd each other. Pinch off the weaker specimens.
I transplant my basil seedlings to their forever-homes once the first set of "true leaves" emerge, within two weeks of germination.
Here again, you have a couple of options.
If you want to grow your basil in one pot or container, choose the largest pot you can lift and move around (and have space for obviously) with sufficient drainage. Plant each basil seedling two inches from its neighbour and do not overcrowd.
Conversely, you can use multiple smaller containers and keep one seedling per pot. I do both methods depending on the culinary herb in question. A plastic yogurt tub works even.
If you have been using a seedling starter medium, now you will definitely need to get proper potting soil to grow your basil. If you want to make your own, here is the ratio I use:
Selecting The Right Container & Potting Soil Mix
Any old container can be used to grow your basil and culinary herbs. You really do not have to spend a lot (or any) money to get containers. Instead of throwing plastic yogurt tubs away, for example, pierce some holes at the bottom and use them over and over again. Any plastic containers in your home are fair game.
I'm partial to unglazed terracotta pots. They are long-lasting, rustic and neutral, but still aesthetically pleasing. Some gardeners do not like terracotta because of the natural porous clay sucking up a lot of the water necessitating more frequent watering. For me, this is actually a bonus because I think it helps prevent root rot and other issues water might cause in the home when added to containers with heavy soil. This might explain why I have never had a mould problem with my seedlings and houseplants despite not doing anything fancy with fans for air circulation.
For the soil, you can buy it ready to go at any garden center or make your own mix.
This is my organic soil recipe:
- 25% garden soil
- 25% fine sand
- 25% coconut coir peat
- 25% vermicompost or composted manure
Do you vermicompost? That's composting with worms. I live in a condo and have a small system I put together myself underneath the sink. It was so successful that I' thinking of starting a second, larger container this winter.
I wrote an article about that too:
From a Cutting:
You can also propagate basil easily from a cutting. In fact, you can keep your personal indoor basil garden going forever with this method.
All you need is a basil cutting that is 4-6 inches long. Cut below a pair of nodes (the bumpy part where the leaves join on the stem) and then remove the bottom 4 leaves.
Place your cutting in a glass of water and leave it alone until the roots start to stimulate and grow. Replace the water every two days or so.
Once the roots have grown out to about 1.5 - 3 inches, it is time to plant them in your soil. Use the above directions I give, they are the same. This will take approximately 4 weeks until you can plant the basil cuttings.
From a Starter Plant:
Buying a starter plant in a grocery store is a great way to get a taste of indoor gardening with basil and other herbs.
The biggest downside is that you will generally have a limited basil selection (one type really), unlike growing from seed where you have an incredible array of choices regarding basil varietals. That choice is one of the most amazing parts of growing your own herbs.
However, there is nothing wrong with this method either! Buy your starter plant, then gently separate at the roots and transplant into multiple containers. You will have a lot of basil in a really short amount of time. Just follow the planting procedures I outline in Starting Basil Indoors From Seed which is right above this.
Pruning basil is essential.
If you do not prune your basil plant as it starts to grow you will not get the lush, bushy herb you are going after but rather a taller, weaker specimen with fewer leaves.
So prune early, and prune often. This is often referred to as pinching.
The first time you prune your basil should be when the plant reaches about 5-6 inches in height and has 4-5 sets of leaves.
Pinch the top set of leaves off, use in some sort of recipe (or just eat right there) and that is all there really is to it.
How Long Does it Take For Basil To Grow?
Basil is a fast-growing and prolific annual that is also kinda fool-proof even for beginners.
Alongside mint, (read How To Grow Mint Indoors here) I highly recommend adding basil as a 'must' to your indoor herb garden.
If planting basil from seed, you should expect to see it sprout in as quickly as four days, although it can take as long as two weeks. Within two weeks after sprouting, the first true basil leaves will emerge.
In as little as four to five weeks you might be harvesting basil. Wait until a stalk has 4 leaves before beginning to harvest.
From cuttings, it will take longer as you will have to wait for the roots to regrow before transplanting. From a starter plant you bought at a nursery or grocery store? Immediately.
How Much Light Does Basil Need?
Basil needs sunlight and warmth, 4-6 hours daily.
When you grow basil indoors, you will need LED plant grow lights as a substitute for the sun to actually be successful. This is especially true in the fall, winter, and early spring months.
In the late spring and summertime here in Toronto, I do not use grow lights at all but move everything outside on my balcony for the season.
Which Grow Lights Should You Choose For Indoor Herbs?
You can find LED plant grow lights second-hand online quite often, but also brand new on Amazon and in Costco. They’re becoming wildly popular and less expensive by the day.
Read some reviews and pick a unit that can work for you and your space. I will cover my own recommendations in another article in the future, so subscribe to my monthly newsletter if you want updates.
I have a big wire rack in my second bedroom for starting seedlings and growing food indoors year-round, but I also have a set of lights mounted underneath one of my kitchen cabinets where all of my herbs go to eventually live once they’re big enough and I can use them in my cooking.
I got those particular lights in Costco for $40 Canadian and they’re completely invisible underneath the cupboard.
Keeping the lights on only at night means I don’t have to stare at LED lights when I’m using my condo living room, and I pay next to nothing in higher electricity costs as it is significantly cheaper at nighttime in Ontario to use electricity, most of which is coming from green sources too.
Does Basil Need Fertilizing?
Do not fertilize your basil plants until the first set of true leaves emerge or even much later on if your soil is nutrient-dense and full of organic matter like worm castings and rotted manure.
Fertilizer is a personal choice. I obviously will recommend only natural and organic sources of plant fertilizer.
If you are vermicomposting, you will 'compost tea' that is absolutely wonderful.
Otherwise, this is an area (alongside soil amendments) that deserves its own in-depth article and I promise to put that out in the future.
I use various fertilizers myself. Outside in my balcony cedar planter, I will even bury fish guts and heads in the garden soil leftover from my fishing trip catches. This results in the most incredible tomatoes and an abundance of healthy growth in a small space.
And many, many more! I personally currently grow: Genovese, Mrs. Burn Lemon & Sacred Tulsi Basil varieties.
So there you have it, this is how you grow basil indoors — more so, how to grow basil indoors successfully which is the real challenge, and telling people to just stick some plants on a windowsill year-round will just not work.
Let me know in the comments what you think and if you have any questions or problems, feel free to ask. Do you grow culinary herbs and other food indoors? I would love to hear from you!