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Organic Lawn Fertilizer

Jessica Gore
Healthy Grass

Choosing organic lawn fertilizer is a simple and effective way to reduce water contamination and preserve the long-term health of your lawn. Organic lawn care keeps grass lush and healthy without concern about chemical contamination of the soil or water. To ensure a successful organic endeavor, plan ahead and choose the best fertilizer for your lawn's specific needs.

When to Apply

The best time to apply organic lawn fertilizer is before you plant the lawn. If you are putting in a new lawn, you can choose grass that has lower nitrogen requirements and competes well against weed species. This will also give you an opportunity to add bulky soil amendments like compost or manure, a task that can be more complicated once your turf is well-established.

Even if you already have an established lawn, timing is critical for the application of organic fertilizers. The nutrients in organic fertilizer are bound up in solid matter and usually require the action of soil microorganisms to be available for plant uptake. Microbial activity is temperature dependent, so if you apply fertilizer in the early spring or late fall your plants might not immediately benefit from your loving care.

Basic Lawn Feeding

There are 16 identified nutrients that growing plants need from the soil. Of these, the following three nutrients are most commonly added for optimal lawn health:

  • Nitrogen: Stimulates lush, green vegetative growth
  • Phosphorus: Necessary for strong root formation
  • Potassium: Essential for general hardiness and disease resistance

Ideally, apply a fertilizer high in nitrogen early in the growing season to stimulate growth, and add an 'autumn fertilizer' rich in phosphorus and potassium later in the summer to prepare your grass for the coming winter.

Types of Organic Lawn Fertilizer

Most organic lawn fertilizer comes from plant sources, but a few have animal or mineral origins. Availability of organic additives will vary depending on your location, so check with your local garden center if you do not see what you are looking for on the shelves.

Bone Meal

Bone meal is one of the earliest organic products to be used as a fertilizer. This product tends to release nutrients most efficiently when used in slightly acidic soils. At three percent nitrogen and 15 percent phosphorus, it is a good choice for an autumn fertilizer.

Blood Meal

At 12 to 15 percent nitrogen, blood meal has the highest nitrogen content of all organic fertilizers. While nitrogen release is still dependant on factors such as soil temperature and pH, it is generally in a highly available form. Anecdotal evidence suggests that the smell of this product may repel garden pests such as deer or rabbits.

Manure and Compost

Of varying nutrient profiles, these substances tend to be the cheapest and most plentiful of organic fertilizers, but can be difficult to apply. Spread lightly over the lawn in late fall to boost organic matter, or make compost tea and apply as a liquid fertilizer. Use only well-composted materials. Improperly composted manure can create nitrogen burn and can leach contaminants into water.

Fish Pellets

A good all-purpose fertilizer, fish pellets are high in nitrogen and phosphorus, but lower in potassium. This product is generally suitable for use any time you are fertilizing, but does have a distinctive fishy aroma.

Feather Meal

A byproduct of poultry processing, feather meal offers about 12 percent nitrogen content. Feather meal takes longer to break down than some organic fertilizers, and so acts as a general slow release nitrogen fertilizer.

Kelp Emulsion

Kelp does not offer enough nitrogen, potassium or phosphorus to act as a standalone fertilizer, but is rich in micronutrients, trace elements, plant hormones and vitamins. Use kelp as an all-purpose supplement in addition to other organic fertilizers.

Corn Gluten Meal

This relic of corn syrup production is marketed as an organic alternative to chemical weed and feed products. Like feather meal, it acts as a slow-release nitrogen fertilizer, but also appears to be an effective pre-emergent weed killer. For best results, apply corn gluten meal early in the spring over the course of several growing seasons.


To some, clover is an unsightly weed, but if you don't mind the look of this happy little legume, it can be an effective, maintenance-free lawn fertilizer for years to come. As a member of the legume family, clover is a nitrogen fixer, and actually adds nitrogen to the soil as it grows.


A natural fertilizer made, not from plant or animal sources, but from mineral deposits left by old seabeds. The product, composed primarily of the mineral glauconite, is mined, dried, and used as a chemical-free source of potassium and iron.

Potential Problems

Organic gardening is as much an art as a science. No matter how carefully you plan, time, and apply your fertilizer, it is still subject to the whims of nature. Watch for the following signs of nutrient deficiency or over-fertilization and learnt to avoid their causes:

  • Chlorosis: Yellowing of the grass is often a sign of nitrogen deficiency. Sprinkle the yellow area with some blood meal.
  • Mottled Yellow Blades: Iron deficiency causes yellow spots to appear along the blades of grass. To combat this problem, add iron sulfate or greensand to the lawn, or decrease the amount of phosphorus added.
  • Yellowing with Brown Margins: This condition indicates potassium deficiency, and is best treated with a light application of greensand.
  • Dark Purplish Patches: Phosphorus deficiency causes leaves to turn purple. On lawns, this manifests as dark purplish patches of grass. To correct, add bone meal or bat guano.

Nature provides everything that grass needs to be healthy. By carefully identifying what your lawn needs and using an appropriate soil amendment, you can keep your lawn lush and green without the use of harmful chemicals.

Organic Lawn Fertilizer