To be honest, finding the best organic fertilizer for sweet potatoes is not an easy task for us. After three years of head-to-head testing over 30 top-rated products in the market, here are our findings:
Here are the best organic fertilizers for sweet potatoes you can buy in 2024:
- Best For Stronger Root: Lilly Miller 100099099
- Super Premium Plant Food (Best For New Growth): Organic Plant Magic
- Best For Higher Yield (Best For New Growth): Espoma GT4
- Best For Big Sweet Potatoes (Best For New Growth): Winchester Gardens WG270
| 4 Best Organic Fertilizers For Sweet Potatoes | ||
|---|---|---|
Best For Stronger Root | Lilly Miller 100099099 | |
Super Premium Plant Food | Organic Plant Magic
| |
Best For Higher Yield | Espoma GT4
| |
Best For Big Sweet Potatoes | Winchester Gardens WG270
| |
Best For Stronger Root: Lilly Miller 100099099
- Encouraging more root development – rich content of potassium and phosphate
- Quality assurance – made in the US
- It has unpleasant odors
Since sweet potatoes are a root vegetable, it is essential to provide good sources of potassium and phosphate to boost more root development. You should look for those fertilizers with a professional 5-10-10 ratio of N-P-K like the Lilly Miller 100099099.
We’re glad that aside from high concentration of potassium and phosphate, this product still provides a good amount of nitrogen to boost the greener leaf growth.
It is 100% made in the United States, which ensures the quality.
Lilly Miller 100099099 is a 4-pound bag to suit a medium-sized sweet potato garden or for years of supply for a single vegetable. The bag is measured by 10-3/4” H x 7” W x 2-1/2” L and has a zipper, which comes in handy for storage.
| Lilly Miller 100099099 Specifications | |
|---|---|
Size | 4 pounds |
Fertilizer Analysis | 5-10-10 |
Highlight Features | rich content of potassium and phosphate made in the US |
Speaking of the best sweet potato fertilizer for stronger roots, we find the Lilly Miller 100099099 is unbeatable.
Super Premium Plant Food: Organic Plant Magic
- Boosting new growth with little chance of disease suffering - beneficial microorganisms & trace minerals
- Pet-friendly, human-safe, and no burns on plant leaves - 100% toxic-free and organic ingredients
- Economical – feeding up to 1,000 square feet/ 0.5-pound bag
- Bad odors
- A bit tricky for beginners to use
Don’t you know that quality seeds and nutritious soil are key for any plants to present their whole genetic potential?
The Organic Plant Magic - Super Premium Plant Food provides the right balance of nitrogen, phosphate, potassium, and calcium, along with millions of beneficial microorganisms and over 55 trace minerals.
It is proven to be capable of building healthy living soil and boost new growth on young sweet potatoes with the minimum disease suffering. The best part is its ingredients: 100% toxic-free and organic to be safe not only on plants but also on humans and pets.
According to the recommended dose, each little bag of ½ pound is enough to feed up to 1,000 square feet of soil or 32 gallons, which is very economical.
| Organic Plant Magic Specifications | |
|---|---|
Size | 0.5 Pounds |
Fertilizer Analysis | 6-5-5 + Calcium |
Highlight Features | beneficial microorganisms & trace minerals 100% toxic-free and organic ingredients |
Whether you grow sweet potatoes from root or transplants, the Organic Plant Magic - Super Premium Plant Food is a great addition to boost new growth.
Best For Higher Yield: Espoma GT4
- Easy to use – granule form
- Ideal for higher yield – providing 15 essential nutrients
- Suitable for organic gardens – enhanced by Espoma’s Bio-tone microbes and all-natural ingredients
- Objectionable smell
The Espoma GT4’s formula is originally developed for pro sweet potato gardeners who want to get higher yields without harming the soil.
It is made of all-natural and organic ingredients for releasing no toxin or sludges to the environment. Enhanced with thousands of Espoma’s Bio-tone microbes, the fertilizer provides 15 essential nutrients to keep sweet potatoes from nutrient deficiencies and potential diseases.
Made in the form of granules, it is easier to use and less messy than liquid fertilizers. The product is a slow-release type that will last for a month or longer each application.
| Espoma GT4 Specifications | |
|---|---|
Size | 4 pounds |
Fertilizer Analysis | 3-4-4 |
Highlight Features | granule form providing 15 essential nutrients enhanced by Espoma’s Bio-tone microbes and all-natural ingredients |
If you are an ambitious sweet potato gardener who want to achieve higher yields, then we highly recommend the Espoma GT4
Best For Big Sweet Potatoes: Winchester Gardens WG270
- Ideal for all-around growth - the 6-3-9 ratio of N-P-K
- Easy to measure – including a spoon
- No complaint
With the 6-3-9 ratio of N-P-K, the Winchester Gardens WG270 is perfect to apply on soil that’s already rich in phosphate.
It provides plenty of potassium (which takes a huge role in the translocation of sugars and starches for the plant growth) and nitrogen (which ensures energy for optimum yield) for overall performance.
The zippered bag design comes in handy for storage and the spoon included in the package is easy to measure.
| Winchester Gardens WG270 Specifications | |
|---|---|
Size | 3 Pounds |
Fertilizer Analysis | 6-3-9 |
Highlight Features | the 6-3-9 ratio of N-P-K a spoon |
Of all the multi-purpose fertilizers that we have tested, the Winchester Gardens WG270 gives the best results for big sweet potatoes.
How To Choose The Best Organic Fertilizer For Sweet Potatoes?
Nutrients
The nutrient analysis for sweet potatoes is varied due to the specific growing stage. For young plants, it is important to feed them with rich nitrogen fertilizer.
But during the production stage, to encourage tasty and big sweet potatoes, you should choose an organic fertilizer that’s lower in nitrogen than phosphorus and potassium.
Nitrogen encourages new leaves and shoots growth while potassium and phosphate boost root development. So, too much nitrogen in your soil during their producing stage is the culprit for scrawny and stunted tubers.
If you are a beginner, here is a quick reference: Most manufacturers include the fertilizer analysis on the product listing. Nitrogen is the first number in the NPK sequence. For example, the Lilly Miller 100099099 has a 5-10-10 ratio, meaning that it contains 5% nitrogen, 10% phosphorus, and 10% potassium.
Bonus: Green sand, kelp meal, and bone meal are the most effective organic ingredients for sweet potatoes due to their low content of nitrogen.
Type Of Fertilizer
There are two common types of fertilizer for sweet potatoes:
- Granular fertilizers
- Water-soluble fertilizers
Each of them works best in certain growing stages of the plant. In detail, granular fertilizers are ideal for young plants or 2-week-old transplants while water-soluble ones are more convenient to apply once the plant begins to spread out.
The reason is you can dilute the fertilizer into water and apply during your regular watering routine.
Which Brands Make The Best Organic Fertilizer For Sweet Potatoes?
Pennington
Pennington, a US brand, has been a quite long time in the market – since 1945, that explains for their insights and knowledge about organic fertilizers. They also become the reliable choice of numerous garden and lawn professionals.
Organic Plant Magic
Organic Plant Magic distinguishes themselves from the rest for the exceptional proprietary process that makes their products easy to use and nearly scent-free, unlike traditional organic fertilizers.
Espoma
Founded in 1929, this is one of the longest-standing US brands for organic fertilizers with over 70 options. At the current, they have successfully produced more than 50 million pounds of organic fertilizer each year to meet endless needs of worldwide gardeners.
FAQs
Do I need to fertilize sweet potatoes?
Yes, you do. Sweet potatoes require feeding during certain growing stages to develop the root system and produce tubers.
How do you increase the yield of a sweet potato?
To increase the yield of a sweet potato, increase the planting depth from 0 to 5†and feed with the right fertilizer.
Why are my sweet potatoes so small?
If your sweet potatoes are so small, the culprit could be the rich content of nitrogen in the soil or the fertilizer that you fed them.
What kind of soil do sweet potatoes like?
Sweet potatoes like to grow in sandy loam soil with a mild acidic pH 5 to 7.5.
Why are the leaves on my sweet potato vine turning yellow?
Nitrogen deficiency or magnesium deficiency can cause the leaves of your sweet potato vines to turn yellow.
Conclusion
This ultimate buying guide and review will come in handy for those who have already determined the needs of their sweet potatoes and your budget. Hopefully, the four top picks of best organic fertilizer for sweet potatoes above are helpful to you. Thanks for reading!
