Collard greens are highly nutritious plants and popular additions to home vegetable gardens. These are typically cold-season crops because they can tolerate lower temperatures, at a time when pests are less interested.

These delicious, leafy crops can be grown in summer, too, with a little extra TLC. If you’ve ever tried growing summer collards, you may have seen them succumb to heartbreaking white powdery mildew, fungal leaf spot, and pest infestations.

Along with sufficient water and sunlight, providing the best Fertilizer for collard greens can help prevent these ailments. 

Fertilizer for Collard Greens 

This article is full of great tips for the best collard green fertilizer, as well as how and when to apply them. But, if time is short, here are my top three fertilizer picks based on effectiveness and ease of use, revealed through my own trials and research. 

Best Liquid Fertilizer

Best Water-Soluble Fertilizer

Miracle-Gro Performance Organics 11-3-8

The organic, water-soluble formula provides rapid soil improvement leading to vigorous growth. 

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Best Organic High Nitrogen Fertilizer

Down to Earth Blood Meal Fertilizer Mix 12-0-0 

Ideal for use in fertile soil, this organic blood meal from Down to Earth increases yield while maintaining nitrogen availability in the soil. 

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Choosing the Best Fertilizer for Collard Greens 

The best fertilizer for your collard greens will be based on your soil structure and its current nutrient content. Whether you’re starting with fertile or poor soil, offering supplemental nutrients will result in larger, more nutritious plants and a higher yield.

A soil test should always be done prior to transplanting seedlings or direct-sowing seeds. This will determine how many vital nutrients are already present in your soil. 

Collard Greens Fertilizer N-P-K Ratio 

For leafy greens, like collards, extra nitrogen will most likely be needed for robust leaf production, regardless of your soil structure. Bone meal, an organic nitrogen source, may be all that’s required for really fertile soil.

The amount of phosphorus and potassium required will be determined by the results of the soil test. 

Potassium plays a critical role in the generation and metabolism of food made through photosynthesis. Phosphorus works in tandem with potassium toward this effort. With so much leaf surface area on collards, efficient photosynthesis is fundamental to a large harvest. 

High Nitrogen Fertilizers 

High nitrogen feeds can quickly improve soil viability in new gardens. But, while a critical nutrient, over-applying nitrogen in established gardens can have detrimental consequences.

Collard greens will flower and fade too early, reducing your yield, and forced growth will leave roots weakened and vulnerable to pests and disease. 

Soil pH for Collard Greens and Nutrient Uptake 

An often-overlooked component of quality soil structure is its pH. For collard greens, the optimal range is between 6.0 and 7.5. Monitoring your soil’s pH will ensure ample nutrient absorption.

Levels outside this range can either block nutrient availability altogether or leave plants exposed to over-fertilizing, as nutrients saturate the soil. Agricultural lime and elemental sulfur will help increase or decrease pH, as needed. 

Granular Vs Liquid Fertilizer 

While there’s little difference in measured nutrients between specific granular and liquid NPKs, there are certainly performance differences.

Liquids are more “mobile”, traveling farther to accommodate both shallow and deep-rooted plants. With granules, roots must seek out nutrients released within a short perimeter.

Granules are better suited for mature plants. Their high salt content can sear the roots of young seedlings. In this case, carefully measured liquids are more successful. 

Liquid Fertilizer for Collard Greens 

For leafy greens, I’ve found liquid fertilizers work best for two reasons:

1. Collards only take 80 days to mature. Faster-acting liquids produce larger plants and yields in less time.
2. Collard greens are considered heavy feeders. Slow-releasing granules may not necessarily match their quick maturity time frame. 

Slow-Release Fertilizer Granules 

The exception to the above scenario is, of course, a blood meal. In granular form, blood meal offers high doses of organic nitrogen that contains far less salt than synthetic options. 

Slow-releasing fertilizers, in general, are less expensive when purchased in bulk compared to liquids, are easier to store, and have longer shelf lives. 

Synthetic Vs Organic Fertilizers for Collard Greens 

When it comes to performance speed, nothing works faster than synthetic fertilizers. Chemical-based feeds are fantastic at hastening maturity in annuals, for early and prolonged color. 

But, the benefit of growing collard greens is their flavor and high nutritional value. The more organic your fertilizer, the healthier your collards are to eat.

Organic fertilizers also improve soil fertility and increase water retention. Continued use will maintain this benefit. 

Best Fertilizer for Collard Greens Reviews 

After careful research and documentation, I’ve narrowed my recommendations to the following five products that performed best as fertilizer for collard greens.

For reference, these were applied to collards in different soil types and environmental conditions to simulate both cold and warm-season growing. 

1. Miracle-Gro Performance Organics 11-3-8

Best Water-Soluble Fertilizer

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Pros

• Quick-release for immediate nutrient absorption
• Rapidly improves soil fertility

Cons

• May exhibit a musky scent 

This water-soluble option from Miracle-Gro promotes a healthy soil structure for sizable collard greens.  When paired with sufficient water and good environmental conditions, fewer pest and fungal issues were observed.

Given its significant nutrient ratio, it made sense to test this product on collard green samples in poor soil and the organic formulation showed impressive results.

Soil testing, conducted before and after, revealed rapid fertility improvement, stimulating vigorous growth. Clearly, boosted by the addition of essential macronutrients.

How To Use: Add two level scoops per gallon of water and apply as a soil soak. Repeat every seven days.

2. Down to Earth Blood Meal 12-0-0

Best Organic High Nitrogen Fertilizer

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Pros

• Great for heavy feeders, like collards and other leafy greens
• A readily available source of organic nitrogen

Cons

• The organic odor may attract pets 

This organic blood meal option from Down to Earth produced large leaves with deep veining which is an indicator of plants with higher nutritional value and delicious flavor.

Applied to seedlings in rich soil, this natural form of nitrogen generated a higher number of successfully harvested plants with few issues. While maintaining sufficient nitrogen availability in the soil. 

How To Use: Add 1 tsp per transplant hole, mix in, and water well. Side dress established plants with 1-2 tips every month during the growing season.

3. Osmocote Smart-Release Plus 15-9-12 

Best Slow-Release Granules

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Pros

• Feeds for up to 6 months
• Little risk of root burn

Cons

• Tiny resin pellets may be visible once nutrients have been delivered 

These smart-release granules offer a significant percentage of macronutrients and eleven essential micronutrients. In testing, these proved to be of the highest benefit to mature collard greens, when applied mid-season. 

Summer-grown collards tend to wilt, mid-day. Using this fertilizer helped to support an increased tolerance to heat and also boosted growth in the final stages of development.

How to use: Sprinkle 3 tablespoons for every 2′ X 2′ area. Work into the top 1-3″ of soil.

4. Burpee Organic Blood Meal 12-0-0 

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Pros

• Repels wildlife
• Naturally formulated for collard greens

Cons

• May clump if exposed to moisture 

From Burpee, comes a second organic blood meal option that infuses leaves with a higher level of nitrogen for more efficient photosynthesis and faster growth. Microbe populations also thrive, with proper use, which will lead to increased soil fertility.

With a natural scent that repels wildlife, this is typically one of the most economical blood meal options on the market, with less required to be effective.

How to use: For seedlings, work in 1 cup for every 20 sq ft of soil area. For established plants work in 2 cups per the same size area. Re-apply every two months.

5. Fox Farm Grow Big Liquid Fertilizer 6-4-4 

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Pros

• A comprehensive blend of major, minor, and micronutrients
• Vigorous organic growth

Cons

• May be available at a slightly higher price point 

My final pick is a liquid concentrate that’s formulated with a broad range of secondary nutrients, trace elements, and base macronutrients.

When mixed with the recommended amounts of water, this organic combination showed the kind of lush and robust growth more commonly seen with synthetic fertilizers.

How to use: As a soil soak, apply 2-3 teaspoons per gallon of water, every other watering. As a foliar spray, mix 1/2 teaspoon per gallon of water and apply using a spray bottle.

How to Fertilize Collard Greens 

Collard greens are considered heavy feeders, so consistency is key. Each of my recommendations has different application instructions. But, maintaining continuous nutrient availability will see your collards sailing through each growth stage.

Remember, the best fertilizer for your collard greens will be based on your soil structure and its current nutrient content.

A soil test should be done at the beginning of the season to determine inherent nutrient content and what needs to be supplemented. The five options we’ve discussed have different NPK formulas to allow you the best option. 

Avoiding Fertilizer Burn 

Similar to fertilizing cabbage, fertilizer burn is a consequence of negative plant interaction with different fertilizer types and improper application. Burning can happen if:

• Plants are over-fertilized
• Granules are applied too close to mature plants
• Liquids are sprayed on leaves in the heat of the day
• “High salt” granules are applied to young plants

To avoid burning the roots and leaves with granules, the Clemson Cooperative Extension recommends side-dressing mature plants, 4 – 6 inches away from their base.

Soil soaks and foliar sprays should be applied in the more excellent hours of the day, to avoid leaf scorch.

When to Fertilize Collard Greens 

Liquids can be safely applied two weeks after seed germination or transplantation. This will allow new roots to establish naturally, without the push of fertilizer. An application frequency of weekly or bi-weekly throughout the growing season is common.

Granules are most effective when worked into the soil, before seeding or transplanting, with a second possible application, mid-season.

Keep in mind that organic blood meal granules have far less salt and provide collard green seedlings with vital nitrogen, without the risk of burn. Synthetic granules have proven more successful when applied mid-season to mature plants. 

How Often to Fertilize 

The frequency will normally be dictated by the brand. Yet, it’s important to note that these are general guidelines. Most fertilizers are designed for use on a broad range of crops, allowing you to adjust how often you fertilize, as needed.

For example, Down to Earth recommends their blood meal granules be applied monthly. Burpee’s blood meal is suggested every two months.

MiracleGro’s water-soluble mix should be applied weekly vs Fox Farm’s concentrate which feeds for two weeks, at a time. This great list of options allows you to pick the best fertilizer for your collard greens. 

Verdict: Best Fertilizer for Collard Greens 

It looks like we have a verdict! The best fertilizer for collards, and other leafy greens, are those that are formulated with a beneficial blend of primary, secondary, and trace nutrients. 

Choose Miracle-Gro Performance Organics if your collards need an instant boost of nutrients due to a lack of soil nutrients or when plants show signs of nutrient deficiencies.

Best Water-Soluble Fertilizer

Miracle-Gro Performance Organics 11-3-8

The organic, water-soluble formula provides rapid soil improvement leading to vigorous growth. 

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Or when an injection of nitrogen is needed to promote healthy leaf development and production, then choose the Down to Earth Blood Meal. 

Remember, the right ratio of these elements (NPK) will promote healthy development through each stage of growth, based on the current nutrient content of your soil.

Best Organic High Nitrogen Fertilizer

Down to Earth Blood Meal Fertilizer Mix 12-0-0 

Ideal for use in fertile soil, this organic blood meal from Down to Earth increases yield while maintaining nitrogen availability in the soil. 

Check Price

FAQ’s Fertilizing Collard Greens