10 Types of Fertilizer You Haven't Tried, but Should

By Oscar Collins

Author bio: Oscar Collins is the editor-in-chief at Modded, where he writes about the outdoors.

Synthetic chemical fertilizers might be cheap and easy to spread, but they also come with risks. They can cause several health issues and contribute to plant nutrient deficiency. Here are 10 unorthodox fertilizers that will bring significant value to your raised garden bed.

10 Types of Fertilizer You Haven't Tried

Poultry Manure

Cow manure is usually the go-to animal dropping for fertilizer, but this option is more for industrial purposes. Small quantities of poultry manure are better for your backyard garden. It contains higher amounts of nitrogen, phosphorus and potassium, the three key fertilizing nutrients plants need the most to grow. Poultry manure’s 5-3-2 NPK ratio makes it the most nitrogen-dominant organic fertilizer. It’s a great starting fertilizer for a new raised garden bed or growing cycle because it works fast in small amounts. Just make sure you use it sparingly to avoid burning out your plants.


Droppings from other avian species are also great manure-based fertilizers. The best kind is seabird guano, which has a 10-10-2 NPK ratio. It also contains trace amounts of other essential nutrients, such as calcium and magnesium. Seabird guano can improve gardens suffering from a nutrient deficiency. Bat guano’s 7-3-1 NPK ratio is also serviceable. This type of fertilizer is most effective in liquid spray form because most of the nutrients are water-soluble. Using it as a spray also enables you to easily apply new layers between plantings. Guano spray is a great solution if you’re having trouble keeping your metal raised garden bed healthy.

Worm Castings

Worms are great signs of healthy soil because they rely on nutrient-rich earth to survive. They also make their environments healthier by warding off hungry pests and aerating the soil. You can collect worm castings — the technical term for worm poop — to create an amazing fertilizer for your raised garden bed. The balanced 2-1-1 NPK ratio is ideal for small-scale agriculture.

Grass Clippings

Grass clippings are tough to beat if you’re looking for a low-cost, low-effort fertilizer. They are slow-reacting fertilizers that become more effective as they decompose. The NPK ratio can vary based on the grass species, but it’s usually around 1-0-1. Look for herbicide-free grass to avoid exposing your plants to unnecessary chemicals. You don’t need much. A 1-inch layer of clippings is enough to sustain a metal raised garden bed for a full growing cycle.


Seaweed is another type of grass that makes great fertilizer. The 1.5-0.75-5 NPK ratio makes it potassium-dominant, so it works best on grain crops. It also acts much faster than grass clippings because most seaweed that reaches the shore is partially decomposed. If you need a quick and cheap solution, there’s an endless supply of free fertilizer on the coastline.

Shell Meal

You can also stay by the coast and collect shellfish scraps to create an effective fertilizer. Before chemical fertilizers became common, New England fishing communities used lobster scraps as fertilizer all the time. Your concoction might have a unique NPK ratio, but the standard for shell meal is 3-3-0. Shellfish also contain lots of calcium and other trace minerals.

Fish Meal

Fish meal is another great seafood-based option for metal raised garden beds. The powerful 4-12-0 NPK ratio helps the nitrogen and phosphorus react to the soil quickly. This organic fertilizer was popular among coastal communities for centuries. It was one of the first things Native Americans taught the pilgrims how to use in the 1600s. 

Bone Meal

Bone meal is a unique organic fertilizer made from ground-up cow bones. Bones are extremely high in phosphorus, as the 4-20-0 NPK ratio demonstrates. They also have high amounts of calcium and magnesium. This fertilizer is perfect for balancing out nitrogen-dense soil that burns your plants. It also provides an excellent food source for flowering crops and fruit trees.

Alfalfa Meal

Alfalfa meal has a modest 2-0-1 NPK ratio, but it’s a fantastic soil conditioner that improves crop health over time. Plant it in your raised garden bed early in the spring before the growing season takes off so it reaches peak effectiveness at the right time. The slow-release quality will help your vegetables stay healthy throughout the season.

Cottonseed Meal

Cottonseed meal is another slow-release organic fertilizer, but it has a more nitrogen-rich 6-2-1 NPK ratio. It acts even more slowly than an alfalfa meal fertilizer, so you should plant it in autumn before the ground freezes. When next spring comes around, the nitrogen will be ready to help your seedlings grow right away.

Organic Solutions Are Everywhere

Today’s fertilizer market is overrun with synthetic chemical solutions that do more harm than good. You shouldn’t have to rely on them to keep your plants healthy. Better organic solutions are everywhere, from the coastlines to your own backyard. Try these unique fertilizers to take your raised garden beds to the next level.