How to grow the best basil

I love basil. I love growing basil, eating basil, looking at basil, thinking about basil, and talking about basil. One of the best things about basil is that, while on first blush it may seem like a challenging plant to grow, in reality it is very easy, prolific, and predictable. As long as you go about it the right way.

When you live in the Pacific Northwest, the first thing you need to know about basil is that it hates our climate. For about nine months every year, our weather is the exact antithesis of what basil prefers. Basil hates 40 degree weather and it hates rain. In fact, any temperature below 50 degrees can result in leaf or stem damage, and the plants often become consumed by gray mold during wet spells. 

However, basil absolutely loves our summer weather. It grows quickly enough that, even without a warm spring or extended fall season, it can be very successful in the garden. 

Like many heat-loving crops, basil needs a head start when grown in temperate climates--if you try seeding it in your garden once the weather gets warm, it just won’t have enough time to grow. Basil can also be slow-growing and finicky if you try to grow your own seedlings indoors, so I recommend purchasing transplants from a nursery when the weather is warm enough to move it right out into your beds.

How and When

It’s best to transplant basil seedlings into the garden once nighttime temperatures are consistently above 50 degrees. Unfortunately, many nurseries begin carrying basil a month before the weather is warm enough for them to go outside. If you ever find yourself looking at basil plants in April, take a few deep breaths and slowly back away from the table. Early planted basil is almost certainly going to fail and need replanting later in the spring. 

Unless we’re having a particularly warm spring, I usually wait until at least June 1 before planting basil outside. In fact, we scheduled the publication date for this article late enough in the spring that basil season is almost upon us. 

So, once the weather warms up and dries out, plant your basil in full sun and space the transplants about six inches apart. Nursery-grown basil transplants often come very crowded. It’s not uncommon to find a 4” pot with eight or ten plants growing closely together. Make sure that you either snip off the excess seedlings or carefully separate them into individual plants when moving them into the garden. 

Prepare the soil as you would for annual vegetable crops, making sure it is loosened and amended with a balanced organic fertilizer. Six or eight basil plants would be a large planting for a typical home garden. If you aren’t planning to make lots of pesto, you will probably be happy with two to four plants. If you are a serious basil fanatic, you may consider succession planting, with the first crop transplanted out in early June and a second crop transplanted out three or four weeks later. 

One of the great things about basil is that, the more often you harvest it, the more it will produce during the season. Each time you pinch back the stems on your basil, it will branch out, effectively giving you two branches where you previously only had one. So the more often you pinch the plant back (and harvest the leaves), the more new, leafing branches you will get. If you can keep up with your basil’s growth, you will end up with stout, bushy plants that demand to be made into near daily servings of pesto and caprese salad.  

To harvest basil, simply use your fingers or a pair of scissors and cut back the top part of any stem that is becoming elongated. You can start to pinch your basil once the plant is 6” tall.  When harvesting, trim each branch back to the next set of leaves. If any branches seem excessively long, you can pinch back two or even three sets of leaves. 

Pinching basil to improve yield

To keep up with a healthy basil plant, you may need to harvest once or twice a week once the plant is established. If the plant begins to flower, redouble your efforts to keep the plant trimmed back. If flower stalks are allowed to develop, new sets of leaves will be much smaller and bitter tasting. If you get way behind on harvesting or your plants just seem prone to flowering, you can try cutting the plants back to the lowest set of leaves and letting them re-grow from the base up. 

Basil doesn’t have to stop with Italian varieties, although common types like Genovese are popular for a reason. If you want to explore a bit this season, add some Thai, Lime, Lemon, or Cinnamon basil to the garden, and then head out to the potting shed to sharpen up your harvest scissors.

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