Can You Put Plant Food on Grass? - Plant Care Guide

Yes, you can absolutely put plant food on grass, as grass itself is a plant that requires nutrients for healthy growth. In fact, what gardeners commonly refer to as "plant food" is essentially fertilizer, and fertilizers are specifically formulated for various plant types, including turfgrass. The key is to use the correct type of plant food (lawn fertilizer) with the right nutrient balance for your grass's specific needs, and to apply it properly to avoid damage.

What is the difference between general "plant food" and lawn fertilizer?

The terms "plant food" and "lawn fertilizer" are often used interchangeably, but there's a crucial distinction in their nutrient ratios and formulations that makes them suited for different types of plants. While both provide essential nutrients, lawn fertilizers are specifically tailored for the unique needs of turfgrass.

General "Plant Food" (Often for Houseplants, Flowers, Vegetables):

• Nutrient Ratios (NPK): General plant foods typically have a more balanced NPK ratio (Nitrogen-Phosphorus-Potassium), or sometimes higher phosphorus (P) and potassium (K) to encourage flowering and fruiting. Examples might be 10-10-10 or 5-10-5.
  • Nitrogen (N): Promotes leafy green growth.
  • Phosphorus (P): Supports root development, flowering, and fruiting.
  • Potassium (K): Aids in overall plant health, stress resistance, and water regulation.
• Micronutrients: Often include a broader range of micronutrients tailored for overall plant health.
• Formulation: Available in various forms like liquid concentrates (often diluted for watering), granular slow-release, or spikes.
• Purpose: Designed to support the growth of individual plants or small beds, promoting vibrant flowers, strong roots, and abundant produce.

Lawn Fertilizer:

• Nutrient Ratios (NPK): Lawn fertilizers almost always have a significantly higher nitrogen (N) content compared to phosphorus (P) and potassium (K). Common ratios include 20-5-10, 30-0-4, or even 46-0-0 (urea for pure nitrogen).
  • High Nitrogen: This is because turfgrass primarily needs nitrogen to develop its dense, green foliage and promote rapid top growth after mowing.
  • Lower Phosphorus & Potassium: While P and K are still important for root development and stress resistance, grass doesn't need as much of them compared to flowering or fruiting plants, especially if soil levels are adequate. Excess phosphorus can also be an environmental concern.
• Micronutrients: Often include iron (Fe) to enhance greening without promoting excessive growth, and sometimes other specific micronutrients beneficial to grass.
• Formulation: Predominantly granular, often with slow-release nitrogen components to provide a steady supply of nutrients over several weeks without causing "surge growth" or burning the lawn. Liquid lawn fertilizers are also available for quick green-up.
• Purpose: Specifically formulated to encourage dense, green turf, strong root systems that resist disease and drought, and even help suppress weeds through healthy competition.

Key Takeaway: While you could technically put general plant food on grass, it's not optimal. Using a general-purpose fertilizer, especially one with higher phosphorus, on an established lawn might not provide the specific high-nitrogen boost grass needs and could introduce unnecessary nutrients that might lead to other problems. Lawn fertilizer is specifically designed for grass's robust foliage growth and is the superior choice for a healthy lawn.

What are the essential nutrients grass needs to thrive?

To thrive and maintain its lush green appearance, grass, like all plants, requires a balanced supply of essential nutrients. These are categorized into macronutrients (needed in larger quantities) and micronutrients (needed in smaller quantities). Understanding these helps in choosing the right "plant food" for your lawn.

Macronutrients (The Big Three - N-P-K):

1. Nitrogen (N):

   • Role: The most critical nutrient for grass. Nitrogen is responsible for lush, green, vigorous growth. It's a primary component of chlorophyll, which is essential for photosynthesis.
   • Signs of Deficiency: Pale green or yellowing leaves (chlorosis), slow growth, thin turf.
   • Why it's High in Lawn Fertilizers: Grass is constantly being cut, removing nitrogen-rich leaf tissue. Therefore, it needs a continuous supply to replace this and maintain density and color.

2. Phosphorus (P):

   • Role: Essential for strong root development, seedling growth, and energy transfer within the plant. It's crucial for establishing new grass.
   • Signs of Deficiency: Stunted growth, purplish discoloration of older leaves, poor root development.
   • Why it's Lower in Established Lawn Fertilizers: Established lawns typically have sufficient phosphorus in the soil. Excess P can lead to environmental issues like nutrient runoff into waterways. Fertilizers for new lawns or seeding mixes often have higher P.

3. Potassium (K):

   • Role: Often called the "stress nutrient," potassium helps with overall plant health, disease resistance, drought tolerance, and cold hardiness. It regulates water and nutrient movement.
   • Signs of Deficiency: Yellowing or browning along leaf margins, increased susceptibility to disease and environmental stress, poor winter survival.

Secondary Macronutrients:

• Calcium (Ca): Important for cell wall structure, root growth, and nutrient uptake.
• Magnesium (Mg): A central component of chlorophyll, vital for photosynthesis. Deficiency causes interveinal chlorosis (yellowing between veins).
• Sulfur (S): Essential for protein and enzyme formation, and aids in chlorophyll production.

Micronutrients (Trace Elements):

• Needed in very small amounts, but deficiencies can still impact grass health.
• Iron (Fe): Crucial for chlorophyll production, leading to a deep green color without excessive top growth. Deficiency causes overall yellowing. Many "lawn tonics" or "weed and feed" products contain iron.
• Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl): Each plays a specific role in plant metabolism and enzyme function.

A soil test is the best way to determine which nutrients your specific lawn needs and in what quantities, allowing you to choose the most appropriate lawn fertilizer for optimal grass health. You can easily find lawn soil testing kits online.

How do you apply plant food (lawn fertilizer) to grass properly?

Applying plant food, specifically lawn fertilizer, to grass properly is essential for maximizing its benefits while avoiding common pitfalls like lawn burn or uneven growth. Correct application ensures the nutrients are distributed evenly and reach the grass roots effectively.

Here’s a step-by-step guide for proper application:

1. Read the Label Carefully:

   • Never skip this step! The fertilizer bag contains vital information specific to that product:
     • Application Rate: How much to apply per square foot or 1,000 square feet.
     • Spreader Settings: Recommended settings for various types of spreaders.
     • Watering Instructions: Whether to water before or after application.
     • Safety Precautions: Wear gloves, eye protection, etc.
     • Seasonal Recommendations: When to apply the product.

2. Determine Your Lawn Size:

   • Measure your lawn (length x width) to get the square footage. This ensures you apply the correct amount of product. Over-application is a leading cause of lawn burn.

3. Choose the Right Spreader:

   • Broadcast/Rotary Spreader: Best for larger lawns. It disperses granules in a wide arc. Overlap wheel tracks by 5-10% to ensure even coverage.
   • Drop Spreader: More precise for smaller lawns or areas near garden beds/patios. It drops granules directly below the hopper. Overlap wheel tracks slightly.
   • Handheld Spreader: Good for very small areas or spot treatments.
   • You can find various lawn fertilizer spreaders to suit your needs.

4. Set Your Spreader Correctly:

   • Adjust your chosen spreader to the setting recommended on your fertilizer bag for that specific product and spreader type.

5. Prepare Your Lawn:

   • Mow your lawn 1-2 days before fertilizing. This helps the granules reach the soil surface more easily.
   • Watering Before Application (Important for some fertilizers): Some granular fertilizers, especially those with pre-emergent herbicides, recommend applying to a dry lawn. Others might recommend a slightly damp lawn. Always follow the label.

6. Apply the Fertilizer Evenly:

   • Wear appropriate safety gear (gloves, long pants, closed-toe shoes).
   • Outline the perimeter of your lawn first, especially with a broadcast spreader, to create a border and prevent over-application in one spot.
   • Walk at a consistent pace to ensure even distribution. Avoid stopping while the spreader is open.
   • Apply in two directions: For best results, apply half the recommended amount in one direction (e.g., North-South) and the other half in a perpendicular direction (East-West). This cross-hatch pattern helps prevent streaks and missed spots.
   • Be careful around edges: Use a drop spreader or edge guard near driveways, sidewalks, and gardens to prevent fertilizer from landing where it's not wanted. Sweep any stray granules off hard surfaces immediately to prevent runoff and staining.

7. Water After Application (Crucial for most granular fertilizers):

   • Immediately after applying granular fertilizer, thoroughly water your lawn. This washes the fertilizer off the grass blades and down into the soil where the roots can absorb it. It also activates the nutrients and helps prevent lawn burn, especially with fast-release nitrogen.
   • Liquid fertilizers are applied with water, so no additional watering is usually needed immediately afterward.

Proper application techniques, combined with reading your product label, are the best way to ensure your grass gets the nutrients it needs without suffering damage.

When is the best time to apply lawn fertilizer?

The best time to apply lawn fertilizer largely depends on your grass type (cool-season vs. warm-season) and your local climate. Timing is critical to ensure the grass effectively absorbs nutrients when it's actively growing and can best utilize them, rather than stressing the plant or encouraging weed growth.

For Cool-Season Grasses (e.g., Fescue, Kentucky Bluegrass, Ryegrass):

These grasses grow most vigorously in the cooler temperatures of spring and fall.

1. Early Spring (March-April):

   • Purpose: Provides nutrients for the initial green-up and growth spurt as the grass comes out of winter dormancy.
   • Fertilizer Type: A slow-release nitrogen fertilizer. This is also a good time for a "weed and feed" product containing a pre-emergent herbicide to prevent crabgrass and other weeds.
   • Timing: Apply when soil temperatures consistently reach 50-55°F (10-13°C), usually around the time forsythia bushes are blooming.

2. Early Fall (September-October):

   • Purpose: This is arguably the most important feeding for cool-season grasses. It helps roots recover from summer stress, promotes strong root growth for winter hardiness, and encourages dense turf for the next spring.
   • Fertilizer Type: A fertilizer higher in nitrogen and potassium to support root development and stress tolerance. Avoid pre-emergents if you plan to overseed.
   • Timing: Apply 6-8 weeks before the first hard frost.

3. Late Fall / Winterizer (Late October-November):

   • Purpose: Provides a final boost of nutrients that the grass can store over winter, leading to an earlier and stronger green-up in spring.
   • Fertilizer Type: A "winterizer" fertilizer, often with high nitrogen and potassium, designed for slow nutrient release.
   • Timing: After the last mow of the season, but before the ground freezes solid.

For Warm-Season Grasses (e.g., Bermuda, Zoysia, St. Augustine, Centipede):

These grasses thrive in warmer temperatures and go dormant in winter.

1. Late Spring (April-June):

   • Purpose: Provides nutrients as the grass breaks dormancy and begins its active growth phase. Helps it green up and establish robust growth.
   • Fertilizer Type: A general-purpose lawn fertilizer high in nitrogen. A pre-emergent herbicide can also be applied in early spring before growth begins, to prevent summer weeds.
   • Timing: Once temperatures are consistently warm and the grass has fully greened up after winter dormancy.

2. Summer (June-August):

   • Purpose: Sustains growth through the hottest part of the year.
   • Fertilizer Type: A moderate application of nitrogen. Avoid heavy nitrogen during intense heat, which can stress the grass.
   • Timing: Apply in mid-summer, about 6-8 weeks after the late spring application.

3. Early Fall (September-October):

   • Purpose: Provides a final feeding to build up nutrient reserves before the grass goes dormant for winter.
   • Fertilizer Type: A lower nitrogen fertilizer or a "winterizer" blend (higher P and K) to support root health and winter hardiness.
   • Timing: About 6-8 weeks before the first hard frost. Avoid fertilizing too late in fall, as new growth stimulated by nitrogen will be susceptible to cold damage.

Always remember that soil testing provides the most accurate recommendations for your specific lawn's needs. Following product label instructions is also paramount. You can find many seasonal lawn fertilizers tailored for different grass types.

Can you use granular plant food on grass?

Yes, you can absolutely use granular plant food on grass, and in fact, it is the most common and often preferred form of fertilizer for lawns. Granular fertilizers provide a slow, steady release of nutrients over time, which is highly beneficial for the sustained growth of turfgrass.

Here's why granular plant food is so effective for grass:

• Slow-Release Nutrients: Many granular lawn fertilizers contain forms of nitrogen that are released gradually by microbial action in the soil or by being coated. This prevents "surge growth" (rapid, unsustainable growth that can make grass weak) and reduces the risk of lawn burn (damage caused by too much concentrated fertilizer). This consistent feeding is ideal for maintaining a healthy, dense lawn.
• Ease of Application: Granular fertilizers are easily applied with a broadcast or drop spreader, allowing for even distribution across large areas.
• Reduced Frequency of Application: Because of their slow-release nature, granular fertilizers typically don't need to be applied as frequently as liquid fertilizers, saving you time and effort.
• No Mixing Required: Unlike liquid concentrates, granular plant food is ready to use directly from the bag (after setting your spreader).

Important Considerations for Granular Application:

• Even Coverage: It is critical to apply granular fertilizer evenly to avoid stripes of dark green grass next to lighter green patches, or worse, burned spots where too much product was concentrated. Using a properly calibrated spreader and applying in a cross-hatch pattern helps achieve this.
• Watering After Application: For most granular fertilizers, it is absolutely essential to water your lawn thoroughly immediately after application. This washes the fertilizer granules off the grass blades and down into the soil, where they can be absorbed by the roots. This step prevents the granules from "burning" the grass blades, especially in hot weather or with fertilizers containing fast-release nitrogen.
• Sweeping Hard Surfaces: Sweep any granular fertilizer that lands on driveways, sidewalks, or patios back onto the lawn or collect it. This prevents the product from dissolving and running off into storm drains, which can harm waterways and cause staining on hard surfaces.

In conclusion, granular plant food is an excellent choice for fertilizing your grass, provided you choose a formula specifically designed for lawns and follow the application and watering instructions on the product label carefully.

What is lawn burn, and how can you prevent it when fertilizing?

Lawn burn is the common term for damage to grass caused by excessive or improper application of fertilizer, resulting in yellowing, browning, or even blackening of the grass blades. It appears as scorched patches or streaks, much like a chemical burn, and can be quite unsightly.

What Causes Lawn Burn?

Lawn burn primarily occurs due to:

1. Too Much Nitrogen: Fertilizers, especially those high in nitrogen, are salts. When too much nitrogen is applied in one spot, the high concentration of salt draws moisture out of the grass blades and roots (a process called osmosis). This dehydration literally "burns" the plant tissue.
2. Improper Watering After Application: If granular fertilizer isn't watered in immediately and thoroughly after application, the granules sit on the grass blades. As they dissolve (from dew, humidity, or light rain), the concentrated salts can burn the blades directly.
3. Uneven Application: Overlapping too much with a spreader or stopping while the spreader is open can dump a concentrated amount of fertilizer in one area.
4. Applying to Wet Grass (for some products): Some granular fertilizers explicitly state to apply to dry grass. If applied to wet grass, the granules can stick to the blades, intensifying contact and increasing the risk of burn.
5. Fertilizing During Drought or Extreme Heat: Grass that is already stressed from drought or extreme heat is more susceptible to fertilizer burn.

How to Prevent Lawn Burn:

Preventing lawn burn involves careful planning and precise application:

1. Read and Follow Label Directions Exactly: This is the most important step. Pay close attention to:

   • Recommended application rates: Never apply more than the label suggests.
   • Spreader settings: Calibrate your spreader according to the product.
   • Watering instructions: Whether to water before or immediately after.
   • Weather conditions: Avoid applying during very hot or dry periods.

2. Measure Your Lawn Accurately:

   • Know the square footage of your lawn to ensure you apply the correct amount of fertilizer. You can use a measuring wheel for large areas.

3. Use a Calibrated Spreader Correctly:

   • Choose the right spreader: Broadcast for large areas, drop for precision.
   • Set the spreader accurately: Use the setting from the fertilizer bag.
   • Walk at a consistent pace: An inconsistent pace leads to uneven distribution.
   • Use a cross-hatch pattern: Apply half the fertilizer in one direction, then the other half perpendicularly. This ensures even coverage and reduces missed spots or overlaps.
   • Close the spreader when stopping: Never let fertilizer sit in an open spreader while stationary.

4. Water Thoroughly Immediately After Application:

   • This is crucial for granular fertilizers. Water the lawn until the granules have dissolved and washed off the grass blades and into the soil. Aim for about 1/4 to 1/2 inch of water. This dilutes the salts and moves them to the root zone.

5. Avoid Fertilizing Stressed Grass:

   • Do not apply fertilizer to a lawn that is experiencing severe drought stress, or during a heatwave when temperatures are consistently above 85-90°F (29-32°C). Wait until conditions improve.

6. Sweep Hard Surfaces:

   • Immediately sweep any stray fertilizer granules off driveways, sidewalks, and patios. This prevents runoff into storm drains and unsightly staining.

By meticulously following these guidelines, you can safely and effectively fertilize your lawn, promoting healthy growth without the risk of unsightly and damaging lawn burn.

Can liquid plant food be used on grass?

Yes, liquid plant food can certainly be used on grass, and it offers several advantages, particularly for quick nutrient uptake and precise application. While granular fertilizers are more common for routine lawn feeding, liquid formulations have their place in a comprehensive lawn care regimen.

Advantages of Liquid Plant Food for Grass:

• Rapid Nutrient Uptake: Liquid fertilizers are immediately available for absorption by the grass blades and roots. This means you can see a quick green-up, often within days, making them ideal for a rapid boost before an event or to correct a deficiency quickly.
• Even Coverage: When applied correctly with a sprayer, liquid fertilizers can provide a very uniform coating of nutrients across the lawn, helping to avoid the streaks and hot spots sometimes seen with granular products.
• Foliar Feeding: Grass can absorb nutrients directly through its leaves (foliar feeding), and liquid fertilizers are particularly effective for this. This is beneficial for quick-acting micronutrient deficiencies like iron.
• Easy to Combine with Other Treatments: Many liquid plant foods can be mixed and applied along with other liquid lawn treatments, such as liquid weed killers or insecticides for lawns, saving time.

How to Apply Liquid Plant Food to Grass:

1. Read the Label: As always, thoroughly read the product label for dilution ratios, application rates, and safety instructions.
2. Dilute Correctly: Liquid plant foods are typically concentrates that need to be diluted with water. Follow the label precisely to avoid over-concentration.
3. Choose a Sprayer:
   • Hose-End Sprayer: These attach directly to your garden hose and automatically mix the concentrate with water as you spray. They are convenient for larger lawns. You can find many hose end sprayers for fertilizer.
   • Pump Sprayer: A handheld pump sprayer is good for smaller areas or precise spot treatments. You manually pump to build pressure and spray.
   • Backpack Sprayer: For larger properties, a backpack sprayer provides extended capacity and allows for more even coverage without frequent refills.
4. Prepare Your Lawn:
   • Mow your lawn 1-2 days before application.
   • Most liquid fertilizers are best applied to a dry lawn so the solution adheres well to the grass blades. Check the label.
5. Apply Evenly:
   • Walk at a consistent pace and ensure you're getting even coverage across the entire lawn. Overlapping slightly is fine, but avoid drenching one spot excessively.
   • Avoid applying too heavily around delicate plants or garden beds.
6. Watering After Application:
   • Since liquid fertilizers are applied with water, typically no immediate additional watering is needed, unless specified by the product label (e.g., to wash it down to the roots for root absorption).

Potential Drawbacks:

• More Frequent Applications: Liquid fertilizers tend to wash away or get used up faster than slow-release granular products, often requiring more frequent applications to maintain consistent nutrient levels.
• Cost: Per application, they can sometimes be more expensive than granular options, depending on the product and concentration.

Despite these minor drawbacks, liquid plant food is a viable and effective option for fertilizing grass, especially when you need a quick boost or precise application.