You’ve worked hard to keep your basil plant growin’. Maybe you even started it from seed. That aromatic little herb has already yielded some pretty tasty leaves, so you expect no different from your next harvest. Only your latest homemade pesto tastes downright bitter. Bleh. What happened to your fresh, sweet basil? A number of factors can cause that tart taste, but it all comes down to care.
Prune, Prune, Prune
If you allow flowers to form on your basil, it can cause the leaves to taste bitter. Be sure to prune away any blossoms before they turn to seed. Pruning your plant will also help keep it healthy and prolong its life.
From the Organic Authority Files
You’ll encourage new growth when you snip your plant’s young leaves. If you snip a section at the stem, be sure to do so directly above a pair of leaves. Then, prune again periodically throughout the growing season. You can prune pretty drastically—to just above the bottom two sets of leaves—about every four weeks. It will persuade your plant to grow, plus it means more delicious basil for you to enjoy!
A Little TLC
Pruning is the trick to preserving your basil’s flavor, but it also needs proper care. Basil requires full sun and consistent watering. If you grow your basil in containers, you’ll need to water more often as the soil dries out quicker. Make sure you’re using a rich, moist, well-drained soil. Don't forget to feed your basil by occasionally adding an organic fertilizer.
Bitter flavor in basil plants can also depend on the variety of plant used. With more than 60 varieties of basil plants available, some offer stronger flavors than others. You may just not be used to the particular flavor of your plant. The most commonly used basil variety, culinary-wise, is sweet basil, but don’t let potentially bitter flavor deter you from trying new varieties. Basil varieties offer a plant-full of potentially mind-blowing flavors, such as cinnamon, anise and lemon basil.