A native of India, neem is an extraordinarily hardy tree that thrives in ecosystems ranging from the Sahara Desert to the wet salty environment of the Florida Keys. The only pests known to harm it are directly related to overwatering: slugs (which are mollusks not insects) and several strains of root rot.
In Florida and other tropical climates, neem quickly becomes a valuable shade tree, growing up to eight feet per year under optimum conditions. In colder climates, neem trees can easily be grown in large pots as highly decorative houseplants, repelling pests such as scale and spider mites that can kill common indoor plants like ficus or palm trees.
For best results, plant your new neem tree in a three-gallon pot for its first year or two, then gradually increase the size of the pot until it’s as large as you can move. They’re happiest spending winter months in a sunny window and summers outdoor. They’re also like goldfish and they’ll only grow as large as their pots allow. Ask your nursery for a premium potting soil that does NOT contain “water-management polymers. These polymers can kill need trees! Please don’t use soil from your yard unless you’re an expert gardener and know exactly what you’re doing.
Water thoroughly after transplanting and then wait until soil is dry to the touch before watering again. If leaves start to wilt in dry climates, spritz them with water or very dilute fish emulsion. Don’t overwater – that’s the easiest way to kill a neem tree. You can plant a “watchflower” like a Vinca or impatience with your neem and only water when the watchflower wilts. If possible, place your new tree in a spot where it is protected from afternoon sun and high winds. Once they’re settled in, however, neem trees are happy in full sun and handle high winds well.
These trees are planted in soiless potting mixture (as required for national and international shipments) but microorganisms have been added to enhance growth and uptake of organic fertilizers. For optimum growth, fertilize weekly with fish emulsion at half the recommended rate and use a balanced organic fertilizer — like 6-6-6 — monthly while the tree is growing.
Neem trees, like many tropical plants, are day-length sensitive and will stop growing in the winter unless supplemental light is provided. If you expect to harvest neem year-round, make sure your tree receives as much natural light as possible during the day, then several hours of artificial light at night during the short days of winter. (It doesn’t have to be a lot of light – a near-by living room lamp is fine.)