10 Best Organic Fertilizer For Plants
Pick out your favorite organic fertilizer for plants to keep your potted pals happy, healthy, and green! Have a look at our recommendations.
Why Use Fertilizer For Plants?
When growing plants indoors, they do not have access to the ecosystem they would if grown outside. Without support, they eat through the resources available in the soil and eventually dry out. Water can bring some minerals, but most also need organic matter.
Along with choosing the right potting soil, using fertilizer is a must. It brings the right kind of nutrients for your plants, as well as protection against pests. Some houseplants need more fertilization while others need less, but sooner or later all indoor plants need some help.
It’s best to use natural, organic fertilizer because it is safer for your plant and for the environment. Artificial fertilizers can burn and damage the plants if not mixed right or if used too often. Besides, the manufacturing process itself pollutes the environment. So to help you keep your plants happy and green, we have 10 suggestions for 100% organic fertilizers. Take a look!
Best Fertilizer For Plants: Our Top Picks
Here are the three fertilizers we think are the best available right now. Check them out, read the reviews, and decide which one is best suited for your needs.
Disclaimer: This article contains affiliate links and if you decide to buy through any of the links found here, we receive a small commission at no extra cost for you. We only suggest products we tested ourselves or products found on our wish list, nothing else. Thank you for your support!
Best Organic Fertilizer For Plants: Top 10
✔️Great for indoor and outdoor
✔️Slow-release
✔️Contains bio-tone
❌Not suitable for pets
❌Bag not resealable
This is a great fertilizer for both indoor and outdoor use, preferred by trees, shrubs, vegetables, and herbs. If you’re looking to fertilize your lawn, it works great for that as well. Spread it according to instructions and water thoroughly to start dissolving the fertilizer.
Because it is a large amount, it is great to get it and refresh your entire greenery set in one go! Remember that it is slow-release so you probably only need it once a year. If using it on already planted plants, bury the right amount under a couple of inches of soil. When using it as a part of the repotting process, mix it with the soil, and distribute it evenly.
Our verdict on this fertilizer for plants
It’s a good fertilizer, with a wide range of uses. We recommend it for beginners who are looking for a one-man-show to help their entire garden.
2. Milorganite Slow-Release Nitrogen Fertilizer
✔️Slow-release
✔️Rich in nitrogen
✔️Covers large areas
❌Contains phosphorus, which may be regulated for outdoor use
This bag is 32lbs, and covers a large area, or can be used for a longer period of time. Your tropical plants will thank you for this nitrogen-rich fertilizer. Use it directly on the surface of the soil or bury it a few inches underground. The slow-release ensures that your plants will have feed for a while. We recommend it for your Aloe, Swiss cheese plant, Yucca tree, as well as some terrarium plants.
Our verdict on this fertilizer for plants
Many gardeners swear by this fertilizer and the results speak for themselves. It is a bit on the pricey side, but the bag covers a large area and can last you years, so it’s a good investment.
3. Down To Earth Organic Kelp Meal
✔️Eco-friendly
✔️Plant-based
✔️Nutrient-rich
❌May attract mice
❌Package rips easily
This fertilizer is made 100% of seaweed from the Atlantic Ocean. This makes it great organic material, perfect for supplementing vegetables, herbs, flowering plants, perennials, and all plants that are used to being fertilized by other leaves. Most shade-loving plants fall in this category because they are used to growing alongside rich vegetation.
Kelp Meal gently stimulates root development and it’s a good replacement for rooting hormones for sturdier plants. This also encourages growth, helps with transplant shock, and makes the plant more resistant overall. As a bonus, it provides a natural source of amino acids, trace minerals that water might not bring, and natural plant hormones.
Our verdict on this fertilizer for plants
We recommend this fertilizer for gardeners looking for an all-in-one that is as close to the natural way their plants feed as possible and eco friendly as well.
4. Joyful Dirt Premium Plant Food and Fertilizer
✔️Easy application
✔️Pet and child safe
✔️Compact design
❌Selective with plants
❌Small amount
This concentrated fertilizer is very easy to use. Just sprinkle a small amount (as per instructions) on the surface of the soil, then water. As this product needs to melt, for drought-tolerant plants it’s best if you mix some in water and apply that instead.
Joyful Dirt is designed by gardeners for gardeners and it works wonders or a range of plants, from basil to the Jade plant. It is great for boosting growth and improving the quality of your plants, as well as for reviving that rescue plant that you picked up half-dead. I personally would choose this for my rose plants and swiss cheese plant.
Our verdict on this fertilizer for plants
This is a great organic fertilizer, that gives a health and resilience boost to most plants. Use carefully, as it is a concentrate and your plants won’t appreciate it if you use too much.
✔️Slow-release
✔️Easy to use
✔️Fast results
❌Attractive for pets
The applicator on the cap makes this fertilizer both easy to apply and convenient. You can sprinkle it on the surface of your pots or under your trees and it will slowly release nutrients over approximately 6 weeks. Mix the grains with soil for better results. For outdoor use on, say, some plants that don’t need much sunlight, just sprinkle some around the base and mix in the top layer of soil. Indoors, you need more accurate measurements, according to the box.
Miracle-Gro is made with organic material and blended with compost, so it will give your large indoor plants a natural boost and support. You will see results in as little as a week! The same organic material attracts the attention of your pets, so store them closed and away from their reach, and be sure to properly bury the granules in the ground.
Our verdict on this fertilizer for plants
Miracle-Gro of all kinds is a staple of gardening, and this organic variant is ready to take you and your plants to the next level! We recommend it for trees and large plants, grown eco-friendly and organic.
6. Neptune’s Harvest Organic Hydrolyzed Fish & Seaweed Fertilizer
✔️Easy to apply
✔️All-purpose
✔️Covers large area
❌Not safe for pets
❌Packaging problems
It is very easy to use this fertilizer because it should be dissolved in water and applied as regular watering. It can be even out in a drip system if that is what you use. This small bottle can feed as much as 2000 sqft of green, so it is very efficient too. It works for most plants, but we recommend it first for outdoor plants and gardens. It should pair very well with asparagus, for example, but feel free to use it on trees, shrubs, and lawns as well.
Indoors, you need to mix a less concentrated solution and be careful not to spill because leftover mix can attract pets and pests. It’s not recommended for pets to come in contact with this product because there is a strong chance they will try to eat it and the concentrate can be harmful.
Our verdict on this fertilizer for plants
This is a very good, all-natural fertilizer with fast, visible effects. We gladly recommend it for your outdoor plants and garden, as well as for most indoor plants.
✔️Easy to apply
✔️Safe for pets
✔️Natural resistance to bugs
❌Small quantity
This fertilizer comes in an easy-to-use shaker that allows you to apply it straight on the soil in your pots. It contains balanced primary, secondary, and micronutrition and it’s locally made in the USA. The cinnamon extract in this organic fertilizer provides protection against bugs and pests, as well as fungi. It contains both fast and slow-release nutrients so it can help your plants both now and later.
Sprinkle 1-2 teaspoons of fertilizer directly to the soil of your plants and water. It’s not going to burn the roots, but don’t apply more than once a month so the plants don’t become dependent on it. It is pet-safe, but still, keep it out of reach of pets and small children.
Our verdict on this fertilizer for plants
This is a great fertilizer for all plants, but we recommend it specifically for tropical plants and succulents because it needs little water to start releasing nutrients.
8. HollandBasics 4-4-4 Organic All-Purpose Fertilizer
✔️Easy to use
✔️Great for all plants
✔️Generous quantity
❌A bit pricey
This fertilizer is great for landscapes and gardens, as well as for potted plants, trees, and shrubs. We would suggest it for your lemon tree, for example! The large amount makes it a great solution for fertilizing your entire collection of greens in one go, in spring. It is enriched with fine rock powder and carbon, guaranteed to provide all the nutrients and minerals your plants need.
Our verdict on this fertilizer for plants
If you have an extensive garden or just many large potted plants, then this is the fertilizer for you!
9. Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer Poly Bag
✔️No GMOs
✔️Slow-release
✔️Contains pro-biotics
❌May attract pets and pests
We suggest using this fertilizer to feed your vegetables and herbs. We mentioned you can grow tomatoes as small indoor plants and this product was designed specifically for them. Rosemary and other herbs could also benefit from using this fertilizer as a compost tea.
It is made locally and sustainably in the USA and is certified non-GMO by several programs and institutes. Dr. Earth contains no synthetic chemicals or toxic ingredients, on the contrary, it is enriched with multi-minerals, proteins, carbohydrates, and humic acids. Be careful not to leave it laying on the surface of the soil, as the organic matter might be attractive to both pets and fungus gnats.
Our verdict on this fertilizer for plants
Try this fertilizer on your plants and get happy, green, and rich growth, as well as delicious herbs and vegetables.
10. Coast of Maine Stonington Lobster & Kelp Plant Food
✔️Slow-release
✔️Easy to spread
✔️Rich in nitrogen
❌A bit pricey
This granular fertilizer is guaranteed to release nutrients consistently, over a long period of time. Its high nitrogen content makes it a great feed for hungry plants, like polka dot plants. The inclusion of porous perlite helps aerate the soil, promotes drainage, and makes it easier for roots to develop.
When fertilizing existing pots, work the fertilizer into the first layer of soil to help it stay in place and start releasing nutrients as soon as you water it. Mix it in the potting soil when replanting in a new pot, as per instructions. Store away from pets.
Our verdict on this fertilizer for plants
Use this fertilizer confidently on your indoor and outdoor plants! It will not only keep your heavy feeders happy, but it will help them grow and develop strong roots.
How To Use Fertilizer For Plants
Most fertilizers come with their own specific instructions, but that doesn’t mean there aren’t a few rules of thumb you can apply to all. For example, do not overfeed your plants. Some fertilizers act and use up quickly, while others are slower. So use them no more frequently than the instructions on the pack say. Even organic, all-natural fertilizers can suffocate a plant if used too much. The same way with a rooting hormone.
Another example is to bury your solid fertilizers. They may arrive as solid pellets or dust, but once they are rehydrated, they become what they have always been: decomposed organic matter. You want a layer of soil between you and that since it can attract the attention of pets and possibly pests if left on the surface.
Only fertilize when your plants can use the nutrients. Some plants are dormant or static in winter and they have no use for extra feed. For instance, a dormant Oxalis will not need fertilizer until it starts growing again.
Lastly, remember that fertilized plants don’t need more water than non-fertilized ones. If anything, they might need a little less watering. Pay attention to your plant and adapt to its needs.
Final Thoughts
We hope you found this list of fertilizers useful and that you found your favorite feed. Which organic fertilizer for plants is your favorite? Is there one you swear by that isn’t on this list? We’d be more than happy to hear all about it in the comment section below!
