The Best Tree Fertilizers

Generally speaking, fertilizers with higher nitrogen content are best for trees, unless your tree is phosphorous or potassium deficient. The best nitrogen-phosphorus-potassium fertilizer ratios are the following: 18-5-9, 27-3-3, or 16-4-8. It’s best to perform a soil test before choosing your best ratio, as you’ll be able to tell exactly what your tree will need.

There are two categories of tree fertilizers, just as with plants—namely, organic and inorganic fertilizers. Organic fertilizers are easy to plant, though slow-releasing and are made of plant and animal materials like manure, bone, and/or cottonseed meal. Though they’re more expensive, they have no threat in harming surrounding plants with substances that do not occur naturally. Inorganic fertilizers are the less expensive of the two, and their nitrogen sources are based in sodium nitrate, ammonium nitrate, and ammonium sulfate. They can also come in various forms, most typically in slow-release, liquid, or water soluble.

Some recommended inorganic fertilizer brands include Miracle-Gro, Bayer Triple Action Landscape Tree and Shrub, Jobe's Tree and Shrub Fertilizer Spikes. Two great organic brands include Organic BioLink and Save-A-Tree. Miracle-Gro is perhaps the most well-known fertilizer brand. Their Shake and Feed Continuous Release All-Purpose Plant food is easy to use and you only have to use it every three months. The Bayer fertilizer also doesn’t need to be applied more than every three months, while the Jobe’s Spikes works without any spraying necessary. Organic BioLink uses a 5-5-5 ratio that you can apply as a soil drench or by spraying every week. Save-A-Tree has a 4-1-3 ratio, which is supposed to prevents trees from being overwhelmed by one compound.