Most people’s basil doesn’t grow into the full, lush basil with large, fragrant leaves that you see online, and they tend to get a few lanky, spindly stems that flower within weeks, then slightly bitter in taste before dying back!
I have personally grown basil for years, and the difference between mediocre basil and exquisite basil almost always comes down to 4 things that need to be done consistently. Fortnuately non are difficult, but most other articles I read online either skip them or the advice is too generic, and it doesn’t explain the why and without the why, it’s hard to do them correctly.
Here are my steps that actually produce the flavourful, aromatic basil that makes you want to cook with it every day.
The Single Most Important Thing is this…Pinching Back
If there is one intervention that differentiates basil plants that are lush and have an amazing aroma from tall, spindly ones, this is it.
Basil wants to flower and set seed as quickly as it is an annual herb that has to do all its growing, flowering, and seeding all in spring and summer to try to guarantee its survival. If you just leave basil, what it’ll do is grow a stem very tall, produce flowers, and the leaves lose their taste.
So if you pinch the leaves, thus crucially removing the growing tip, it interrupts this process. When you remove the top of the stem just above a pair of leaves, the basil responds by sending out two new shoots from the nodes below it.
These shoots can be pinched again, and you essentially turn a single stem into a bush.
I personally do this every ten days roughly so that my basil stays around 6-8 inches tall but ever so bushy! Crucially, you have to remove and pinch back any flower buds when ever you see them to keep the basil in leaf-growing mode.
These flower buds can be small and easy to miss at first, as they appear as a small cluster at the tip of the stem.
Pinch them out quickly, because as we discussed, the quality of the leaves drops quickly in terms of flavour and aroma.
I have personally pinched my basil plants so often that they’ve produced leaves into Fall (Autumn) from sowing the seeds on my windowsill in the early spring.
I bag up and freeze the surplus or dry it out for later use.
Pot Size Matters More Than Most People Realise
Basil is quite the hungry and thirsty plant with a good-sized root system. If your pot is too small, this means less soil that dries out more quickly and fewer nutrients, and the roots eventually become pot-bound.
The result is a basil with poor growth that has a greater risk of wilting more often, which is contrary to the lush, flavourful plant we all love!
So when giving my friends and family advice, it’s best to say go with a pot that is one size larger than you’d think necessary. For example…as single repotted supermarket basil plant or seedling wants a pot of around 15-20 cm or 6 to 8 inches in diameter. The bigger pot means more soil, which retains moisture, therefore you are likely to avoid the biggest problem with growing basil, which is wilting. The larger pot also has more soil and more nutrients, and of course, more room for the root system to establish itself.
I grow my productive basil outdoors in larger ceramic or even plastic pots that are 30 cm or 12 inches across. This is a really generous size but these plants always out perform my basil in smaller pots in terms of leaf size, thick stems, overall harvest etc.
Getting the Light and Position Right
So this can be tricky depending on where you live, and you have to use some of your own judgement for this…in cooler climates, I find basil grows best in full sun, and I move it to shade in the afternoon on the hottest summer days to prevent it from wilting.
However, if you are in a really hot, arid area such as southern California or southern Europe, I find that basil grows best in morning sun with afternoon shade. This strikes the right balance of light intensity and avoiding heat stress.
Through my experiments, I have always found that outdoor basil grows better than indoor basil (I sow them indoors on my windowsill before potting them up and putting them outside) due to increased light intensity, humidity and the natural cycle of temperatures.
The flavour is often more intense with outdoor basil, but do not let that stop you from growing it on your windowsill, as this is still significantly better than dried basil. The freshness really makes the difference.
South-facing windows are always best for indoor basil.
One key thing I learned from growing basil outdoors is this…don’t put it outdoors too early, as basil is cold sensitive (it’s tropical in origin) and temperatures below 10°C or 50°F are going to cause it to go black or stall growth. So what I do is wait until temperatures are reliably above 10°C at night, which often means waiting till May. A cold snap can really ruin its progress.
This is arguably a good reason to grow it indoors if you have a nice sunny windowsill.
Feeding For Leaf Production
A basil plant that you’re harvesting from every 7 to 10 days is using a lot of energy. Most plants, of course, remain largely undisturbed, whereas basil that is harvested often has to generate more leaves, and it needs nutrients for this.
I feed my basil every 2 weeks during the growing season with a fertiliser, diluted to half strength (as basil is sensitive to strong fertiliser). More is not more when it comes to fertilizer as too much makes the basil grow floppy and decreases the concentration of essential oils that are responsible for the aroma and taste.
You can use tomato fertilizer which has less nitrogen (the nitrogen causes the floppy growth), which works well. I personally love to grow anything edible in an organic way…so I use liquid seaweed (as recommended by UK gardener Monty Don!) or my own organic fertilizer that I make from comfrey leaves.
The liquid seaweed feed works great, and I have really tasty leaves, and of course is 100% natural without chemicals.
Watering…The Rhythm That Makes The Difference
Basil wants a balance of consistently moist soil rather than boggy conditions. What I do is wait until the top 1 cm or half inch is somewhat dry (not bone dry) and then give it a good soak. The goal with watering should always be to ensure the compost is evenly moist.
When I water my basil I give it a generous soak and assess the weight. After watering the pot should feel reassuringly heavy and it gets lighter as it dries. If I pick it up and its lighter then it was I know I need to water.
I would also urge you to water at the base of the basil rather than over the leaves, as wet foliage can increase the risk of fungal problems.
Whenever I water at the base, I haven’t had any problems with fungal disease.
I would warn that outdoor basil in terracotta can dry out very quickly (as terracotta is porous), which is why I use a ceramic or plastic pot, as they dry out less quickly, which prevents my basil from wilting.
My Honest Truth About Basil’s Lifespan
It’s important to remember that even with perfect care, our basil plants are annuals that flower, seed and die back irrespective of how diligently you pinch them. However, pinching helps to increase its lifespan by about 3 or 4 times as long and increases your harvest.
I often sow seeds every 2 to 4 weeks in the Spring to ensure I have a good supply of basil (and a surplus through the growing season rather than a massive glut all at once.
Growing basil and seeing results from these techniques? I’d love to hear about it in the comments below.