Murraya koenigii, also known as sweet neem, curry leaf and kadi patta, is primarily a culinary herb, rather than a medicinal plant. It’s easy to grow in a pot in locations where winter temperatures dip below freezing, or you can plant it in the ground in frost-free zones.
In either case, start it in an eight-inch pot with premium potting soil, NOT topsoil or soil labeled as “water managing.” Water well when you first transplant it, then wait until it’s dry before watering again. (The easiest way to gauge when to water is to guess its weight. If it weighs about the same as a half-gallon of milk after you’ve watered it well, wait until it weighs about a quart before you water again.)
In locations that freeze, you’ll want to transplant into a larger pot in about two years but starting it off in a large pot makes it very easy to overwater. You’ll need to keep it in a pot that spends the summer outdoors in full or nearly full sun and comes in for the winter. They grow best with at least five hours of direct sunlight but thrive under grow lights if you don’t have that much natural light.
In USDA zones 11 to 9, they can go in the ground after their first summer in a pot. (Planting them in the ground while they’re still very small is not recommended. They don’t seem to attract insect pests but they need to be protected from foot traffic and weedwhackers.)
They are relatively heavy feeders, particularly if you’re harvesting the leaves often. We use Neptune’s Harvest 2-3-1 every other week during the summer; growth naturally slows during the short days of winter unless you have grow lights that fool the plants into thinking it’s summer all year long.
You can harvest sweet neem leaves by picking the older leaves from the bottom of the plant, or by cutting off the top of the plant. Cutting from the top will help create a bushier plant that is more likely to throw runners that can become their own plants. Never cut more than 1/3 of the growth at a time and plan on maintaining consistent fertilizer applications.
For best results, use fresh leaves but they can be stored in the refrigerator for about two weeks wrapped in a damp (not wet) paper towel and in a sealed bag. They also can be frozen but they’ll lose some flavor. We don’t recommend drying them unless you have no other choice.
Sweet neem trees can grow up to 20 feet tall but most only reach about eight feet, even outside in the tropics. If you have a small yard, you may want to keep the sweet neem in a pot. They spread by runners that some people call invasive. They also will have pretty white flowers with an amazing scent, followed by fruit about the size of a small grape. The seeds should be planted right after they turn black and are easy to remove from the “mama” plant. They are self-fertile so you just need one plant to get viable seeds. If you don’t want seedlings, cut the flowers off so the plant doesn’t concentrate its energy on reproducing. CAUTION: the seeds are toxic so do not eat them.