The Best Organic Fertilizers for a Fruitful Garden and the Lushest Lawn

When it's time to get your garden in gear or revive a lawn that's a little lackluster, a great fertilizer is a crucial growth factor. But there are pretty significant differences between organic fertilizers (our preference, but perhaps we're a little biased) and synthetic fertilizers (which are actually pretty problematic). Synthetic, or chemical, fertilizers tend to compromise the quality of your soil and use toxic ingredients ranging from lead to sulfur, which leech into your fruits and veggies. Plus, they're responsible for a great deal of nitrogen pollution.

Best Overall: Back to the Roots Organic Premium Blend All-Purpose Plant Food ($9)

Best for Flowers: Earth Safe Organics Cottonseed Meal 7-3-2 ($16)

Best for Fruits and Vegetables: Burpee Organic Blood Meal Fertilizer ($15, was $17)

Best for Tomatoes: Jobe’s Organics Granular Garden Fertilizer, ($9.50, was $16)

Best for Grass: GS Plant Foods Store Organic Kelp Fertilizer, $40

Best for Indoor Plants: FoxFarm Happy Frog All-Purpose Fertilizer ($16.50)

Organic fertilizers, on the other hand, don't rely on chemicals to get the job done. Sure, the chemicals deliver nutrients to the plants quickly, but over the long haul, they corrupt the soil (and ultimately, the plants). Instead, organic fertilizers use organic matter to feed your fruits and veggies. Over the long haul, these fertilizers help strengthen the soil structure, creating quite literally a fertile ground from which your plants can absorb more nutrients and water in the long-term.

You'll find a few different types of organic fertilizers on the market. Some use animal-based ingredients like blood meal, fish meal and worm castings. Others use plant-based ingredients like cottonseed, alfalfa, and kelp. And then there are organic fertilizers based on minerals like rock phosphate and lime. Here's the dirt on our favorite organic fertilizers that can give new life to your plants.

Nourish your vegetable garden or pump up your shrubs: This Back to the Roots blend is a great all-around organic fertilizer, and it's as natural as they come. It's totally vegan, packed with plant-based ingredients like alfalfa and kelp (a renewable resource), plus minerals like rock phosphate, which helps with photosynthesis. It's even packaged partially in post-consumer recycled materials.

This liquid Earthsafe Organics fertilizer is made using cottonseed meal, which is harvested from cotton seeds after they've been pressed for oil — so not only is this fertilizer vegan, but it also uses plant byproducts. It's known to deliver macro- and micronutrients to many kinds of flowers, including hydrangeas and azaleas, as well as fruits and veggies.

"I put about 1/2 cup around a newly planted fruit tree. Even the grass around the tree was greener than the rest of the lawn," one reviewer wrote.

Blood meal is a big nitrogen booster, so if you've got nitrogen-feeding plants like cucumbers, spinach, and broccoli — or even flowers — in your garden, Burpee Organic Blood Meal fertilizer is a popular pick. Just like it sounds, blood meal is derived from dried animal blood, which can naturally repel hungry intruders like deer and rabbits.

"Our garden truly thrives, and produces so many fruits and vegetables," wrote one of thousands of five-star reviewers.

Tomatoes need nitrogen, phosphorous, and potassium to thrive, and this organic fertilizer by Jobe Organics delivers. It also contains Biozome, the brand's own blend of beneficial microorganisms to fortify soil, strengthen plants, and prevent disease. "My tomato plants flourished within weeks, with noticeably more vibrant leaves and earlier fruit production," a gardener wrote.

There are a variety of ingredients that are great for a variety of grasses, but kelp is an overall hero for all kinds of lawns — and a plant-based one at that. This organic kelp fertilizer in liquid form can help with root strength, grass density and color, and hardiness. It also has seaweed extract to protect your grass from harsh elements.

"This product works great to battle heat stress and to help the lawn bounce back from disease. I mean literal results overnight," one fan wrote.

Getting indoor plants to thrive is a feat unto itself, but Fox Farm's Happy Frog organic fertilizer could help make your thumb a little greener. It uses mycorrhizal fungi to help roots absorb water and produce verdant foliage on your houseplants. "Definitely worth the money. Plants are growing and looking healthy," one shopper wrote.