We’re regularly asked how much water a neem tree needs. The short answer: it depends.
The size of the tree, and the size of its pot, how much sun it receives, how high the humidity might be and even the time of the year all play a role in how much water a neem tree needs. A large tree growing in a small pot in full summer sun might need water twice a day. You would kill a smaller neem tree growing in a window with less sun with that much water.
That’s why we often recommend neem tree growers use “watchflowers” to determine when the soil is dry. You can plant the watchflower in the same pot as the neem tree, preferably at the same time you plant your tree. Water them both well and then wait for the watchflower to wilt in the morning before watering.
You can use a wide variety of plants as watchflowers. Vincas, or periwinkles, are best for trees growing in full sun. Impatience and peace lilies are best in shaded spots. We also have native violets available most of the year.
Be sure to wait until the watchflower wilts in the morning before watering. Impatience and peace lilies may wilt in the sun, no matter how much water is in the soil. If you wait until they’re wilting in the morning, you know the soil is dry all the way down.
IMPORTANT NOTE: If your neem tree is wilting in the sun, move it to a location where it gets less direct light in the afternoon. Morning sun is best until your tree has handled the stress of transplanting, then you can move it back into the sun. Do not water a neem tree just because it’s wilting though – unless you’re absolutely sure it’s dry all the way down, too much water will cause root rot and kill the tree!