Without a doubt, onions have become a stable vegetable in just about any garden mainly because they are easy to grow and to care for.
However, even though they don’t require any special conditions to grow, onions are known as “heavy feeders”, meaning that they need fertilizing in order to produce high yields in time for harvest.
Nutritional needs of your onion crop will vary depending on the type of the soil in your garden, so it’s crucial to choose the right fertilizer.
In this post, we are going to discuss some of the best options to look for when choosing the best onion fertilizer.
What is the best fertilizer for onions?
The quick answer is that onions require a fertilizer that is high in nitrogen. This will help them develop a good root system and overall a healthier plant. A healthier plant, in turn, is going to produce better onions. Depending on the type of plant food used, it should be applied every couple of weeks to ensure they get a good steady supply of food.
Here is a quick preview of our top 4 options on the market.
- Jobe’s Organics Blood Meal 12-0-0 Organic Nitrogen
- Alaska Fish Fertilizer 5-1-1 Concentrate
- Fox Farm FX14092 Grow Big Liquid Concentrate
- Urban Farmer Organic Onion Fertilizer
To learn more about them individually, please keep reading.
What To Look For In A Good Onion Fertilizer
Because onions have a shallow root system, they need nutrient-rich soil to thrive. Using the right fertilizer will boost their growth and help the plant produce large, healthy bulbs.
When it comes to choosing the right fertilizer for your onion crops, the main thing you should pay attention to is the percentage of nitrogen, phosphorus (phosphate) and potassium (potash) in the product, more commonly known as NPK ratio.
For onion crops, you should choose fertilizer mixtures with higher nitrogen levels. Not only that this nutrient increases the yield, but nitrogen also improves bulb quality, storability, and disease resistance.
For most garden soils, a nitrogen-based fertilizer or a balanced fertilizer with an NPK ratio of 16-6-4 is the best choice.
However, if you already use organic compost, or the soil in your garden already has enough nitrogen, using potash or phosphate-based fertilizer can benefit your onion crops without oversaturating the soil or burning your plants.
In addition, you might want to provide your onion crop with micronutrients like copper, zinc, and manganese, especially if you’re growing them on poor garden soil.
These trace minerals and minor nutrients are essential for abundant crop yield, as they provide optimum soil quality.
An Closer Look At My Top Picks
- Granular – Slow Release
- Nutrient Ratio: 12-0-0
- Apply every 3 to 4 weeks
The first option that we want to take a closer look at is, Jobe’s Organics Blood Meal 12-0-0 Organic
For Nitrogen-loving plants such as onions, you can’t go wrong with a 12-0-0 NPK ratio! This organic granular fertilizer is made of 100% organic blood meal and helps you grow bigger, healthier bulbs.
It’s especially recommended for gardens with soils poor in nitrogen, and for balancing nutrients in your compost pile.
Since it’s completely natural, this fertilizer will release the nutrients more slowly and evenly into the soil. This means you’ll get uniform results and you won’t have to apply it as often, so this 3 lb bag can last a long time.
Application Tips: Apply this fertilizer 3 to 4 weeks after you’ve planted your onion crop, repeating monthly until the onions start to bulb. Use ½ to 1 cup of fertilizer per foot of onion height for optimal results.
Apart from proven growth benefits to onions, Jobe’s Organics Blood Meal is also safe to use around kids and pets.
- Nutrient Ratio: 5-1-1
- Apply every 3 to 4 weeks
Next on our list is Alaska Fish Fertilizer 5-1-1 Concentrate.
A perfect choice for organic and biodynamic gardens, this all-natural, eco-friendly onion fertilizer promotes quick growth and abundant yields. The 5-1-1 NPK ratio of this sea fish-based mixture is suitable for onion crops in gardens with moderately fertile soil or soil with lower levels of nitrogen.
Even though it is fish-based, this product doesn’t have a strong, unpleasant smell, as it’s deodorized with wintergreen oil.
The natural formula of this fertilizer is optimal for onion crops in most gardens, as it provides a high percentage of nitrogen, with lower levels of phosphate and potash to provide well-rounded soil nutrition.
In case the soil in your garden is particularly poor in nitrogen, a fertilizer with higher levels of this nutrient would be a better choice.
Application Tips: To get the desired results, mix 1 to 4 tablespoons of the fertilizer in a gallon of water, and water the crops with the mixture every 3 to 4 weeks.
In addition, Alaska Fish Fertilizer is on the Organic Materials Review Institutes approved list.
- Nutrient Ratio: 6-4-4
- Liquid Food
- Apply every 2 weeks
Number three on our list is Fox Farm FX14092 Grow Big Liquid Concentrate
With a well-balanced, 6-4-4 NPK ratio and a variety of minor and micro nutrients, this liquid fertilizer will your onions grow like crazy.
Extra strong and organic-based, Fox Farm’s Grow Big liquid fertilizer promotes extraordinary growth, and the unique blend of nutrients will nourish your onion plants and improve the overall quality of the crop.
Due to the combination of major nutrients in a balanced ratio and trace minerals and nutrients such as iron, manganese, copper, and zinc, this fertilizer has an instant effect on your crops.
Since a little bit of this potent fertilizer goes a long way, this 1-pint bottle is more than enough to keep you covered during the growing season.
Application Tips: Although instructions suggest using 2 to 3 teaspoons diluted in a gallon of water every other watering, take care not to overfeed your crops. Watering your onions with this fertilizer every 2 weeks will be more than enough to see amazing results.
- Nutrient Ratio: 3-4-4
- Specifically formulated for onions
- Contains Sulphur
- No GMO’s
- All Natural
The last and certainly not the least on our list is the Urban Farmer Organic Onion Fertilizer.
Specially formulated to improve onion’s taste, health, and size, this all-natural, organic onion fertilizer does wonders for your crop.
With a 3-4-4 NPK ratio, as well as added minerals and nutrients, Urban Farmer’s Organic Onion Fertilizer will enrich your garden soil and make your onions taste and look better.
Although it’s great for enhancing the growth of the bulbs and their health, like many other quality fertilizers, this onion fertilizer in its ingredients has Sulphur, which gives it a slight advantage over its competitors.
The reason why the addition of Sulphur to the mix is important is that this element is what gives onions their amazing taste. So, when you have Sulphur in your fertilizer, you can be sure your onions will taste better than they did ever before.
The 3 lb bag is enough to feed a 120-foot row of onions, and it’s added to the soil just before planting and when your onion plants grow to be 1 foot tall.
Is Miracle Grow Good For Onions?
Yes, Miracle Grow is good for onions. Just like any other fertilizer you want to look for one that is high in Nitrogen. I really like what Miracle-Gro Performance Organics has to offer.
It has a good all around nutrient ratio for most vegetables of 9-2-7. Notice how it is high in nitrogen which will give you that healthy plant growth. Remember healthy plants produce quality onions.
In addition. it is granular meaning slow release, ensuring that your crops get a steady stream of plant food.
Is chicken manure good for onions?
Yes, because chicken manure is high in nitrogen it is great for onions and it should definitely be used as an organic fertilizer for your crops.
However, it is important to note that fresh chicken manure applied directly to your plants can do more harm than good.
For that reason, if you are planning on using chicken manure it would be better to compost it first. This allows time for those powerful nutrients to breakdown.
After some time composting, simply apply it directly the soil, work it into the soil with a shovel, plant your onions and lastly watch them grow.
What fertilizers do onions like?
Onions prefer a fertilizer that has a high amount of nitrogen. Another ingredient that onions love in their plant food is ammonium sulfate. this is because ammonium sulfate tends to lower the soil’s ph level.
Keep in mind that the target pH range for onions is between 6.5 to 8.0. It is always best to test your soil before applying addition nutrients.
Is Potash good for onions?
Yes, potash is good for onions. In fact, some gardeners have said that adding potash to their onions yields a stronger tasting onion.
Keep in mind the recommended amount is 4.8 ounces of potash per 100 square feet. Wood ashes can be a great source of potash.
So what is the best fertilizer for Onions?
In the end, the decision should be yours. All of the products mentioned in the article are a good choice for fertilizing onion crops, but, depending on your budget, preferences, and the soil in your garden, some might perform better in your garden than others. Job’s and Alaska’s fertilizers are an overall great choice for nitrogen-poor gardens, while Fox Farm’s and Urban Farmer’s fertilizers are a better fit for loamy, nutrient-balanced soils.
Now let’s turn it over to you. What have you found to be the best fertilizer for onions? Please share your thoughts in the comments below.