Preen Garden Weed Preventer + Plant Food Review


Preen Garden Weed Preventer + Plant Food is a product designed to tackle the challenging issue of weed control, especially in areas prone to weed infestation due to environmental conditions such as windblown seeds in arid, high desert climates. The presenter, living in a rural setting surrounded by fields and pastures, shares firsthand experience with the relentless invasion of weeds like dandelions and tumbleweeds, highlighting the constant battle against new weed seeds in cleared planting areas.

Product details

  • Active ingredients: Trifluralin
  • Package size: 5.625 lbs, 13 lbs, 16 lbs, 31.5 lbs
  • Fertilizer ratio: 9-12-9
  • Selective: No
  • Emergence: Pre-emergent
  • Required equipment: None
  • Price range: Moderate

What is Preen Garden Weed Preventer + Plant Food

Preen Garden Weed Preventer + Plant Food is a gardening product designed to simultaneously prevent weeds from sprouting and nourish plants with essential nutrients. The primary function of this product is to inhibit the germination of weed seeds in the soil, thereby reducing the need for manual weeding around established plants in gardens and landscapes. It contains a pre-emergent herbicide, typically Trifluralin, which targets the weed seeds before they have a chance to grow, without harming existing plants.

Preen Garden Weed Preventer plus Plant Food

In addition to weed prevention, this product also includes plant food to support the growth and health of garden plants. This dual-action formula makes it a convenient option for gardeners looking to maintain weed-free ornamental beds, vegetable gardens, and other landscaped areas while also providing their plants with a nutritional boost.

The application process involves spreading the granules evenly over the soil surface and watering them in, which activates the herbicide and helps to distribute the nutrients. It’s important for users to avoid applying this product in areas where they intend to sow seeds, as it will prevent their germination. With careful use, Preen Garden Weed Preventer + Plant Food can be an effective tool for keeping gardens looking tidy and supporting plant health.

Application of Preen Garden Weed Preventer + Plant Food

Applying Preen Garden Weed Preventer + Plant Food involves a few simple steps to ensure effective weed control while providing essential nutrients to your plants. Initially, it’s essential to clear the area of any existing weeds and prepare the soil to create an optimal environment for the product to work. The granules should be spread evenly across the soil using the convenient shake applicator that comes with the packaging, ensuring a uniform coverage that helps prevent new weed seeds from germinating. After spreading the granules, a thorough watering is required to activate the herbicide and plant food, allowing them to penetrate the soil and begin their action.

applying Preen Garden Weed Preventer from a yellow container

It’s important to note that while Preen is effective at preventing new weeds from sprouting, it does not have the capability to kill already established weeds or those that spread through methods other than seed germination, such as runners or root systems found in plants like bindweed or crabgrass. This distinction highlights the need for gardeners to maintain regular weed management practices alongside the use of Preen to ensure a well-maintained, weed-free garden. By following these application steps, gardeners can provide a solid foundation for plant growth and weed prevention, keeping their gardens looking beautiful and healthy.

Where to Use a Preen Gardeen Weed Preventer + Plant Food

Preen Garden Weed Preventer + Plant Food is ideally suited for use in various garden settings where weed control is desired without harming existing plants, and where additional plant nutrition is beneficial. The product is particularly effective in ornamental flower beds, where it prevents weeds from competing with decorative plants for nutrients and sunlight, while simultaneously providing essential nutrients to encourage vibrant blooms and healthy growth.

applying Preen Garden Weed Preventer from a yellow container

In vegetable gardens and around established fruit trees and bushes, Preen can also be applied with caution, taking care to avoid areas where seeds will be sown, as it will inhibit their germination. It’s an excellent choice for use around perennials and in areas planted with bulbs, where it can be applied after the plants have emerged from the ground. Additionally, Preen is useful in landscaped areas with shrubs and trees, under and around which it can prevent weed growth without the need for frequent manual weeding. It’s also effective in non-planting areas such as gravel paths, driveways, and along fence lines, where it can help to maintain a neat appearance by preventing unwanted weed growth. The extended control versions of Preen are particularly useful in these areas, offering longer-lasting weed prevention. However, it’s essential to consider environmental precautions, especially regarding potential runoff to water bodies, given the product’s toxicity to aquatic life.

Where not to use Preen Garden Weed Preventer + Plant Food

Seed Starting Areas

Preen is designed to prevent seed germination, which is great for controlling weeds but not for areas where you want your flowers, vegetables, or herbs to grow from seeds. If you apply Preen in these areas, your desired seeds will also be prevented from sprouting, leading to unsuccessful planting efforts.

Vibrant garden bed with a variety of green and purple leafy vegetables under bright sunlight
Person watering small, leafless plants in a garden bed next to a wooden fence

Areas with Perennial Weeds Spreading by Runners or Roots

Weeds like bindweed and crabgrass are notorious for their ability to spread through runners (stolons) and underground roots (rhizomes). Preen targets seed germination and will not be effective against these types of weeds. Using it in such areas would not only be ineffective but also might give a false sense of weed control, allowing these weeds to become more established.

Near Water Bodies

Preen contains chemicals that can be harmful to aquatic organisms. When used near water bodies, there’s a risk of runoff carrying these chemicals into the water, potentially causing harm to fish, plants, and other aquatic life. It’s crucial to maintain a safe distance from these areas to prevent contamination and protect the aquatic ecosystem.

Pond with water plants and fish
Wooden garden bed with plants

Edible Gardens without Established Plants

While Preen can be used around established plants, it should be used with caution in vegetable gardens or any area intended for growing food crops from seeds. The product could prevent the germination of your vegetable seeds, impacting your garden’s yield. It’s best to use Preen only around established plants where no direct seeding will occur.

Lawns or Grass Areas Intended for Seeding

If you’re planning to establish a new lawn or fill in patches with grass seed, avoid using Preen in these areas. It will inhibit the germination of grass seeds, preventing your lawn from establishing properly. Preen is not suitable for use in lawns where seeding is part of lawn care and maintenance.

Hand sowing grass seeds over a patch of soil amidst green grass
Person transplanting young green plants from a seedling tray to soil

Newly Transplanted Areas

Young, newly transplanted seedlings are vulnerable and need time to establish their root systems. Applying Preen around these plants could stress them further and inhibit their growth. It’s best to wait until plants are well-established and showing signs of healthy growth before considering the application of any weed preventer.

Indoor Plants or Containers

The controlled environment of indoor gardening and the limited space of container plants do not lend themselves well to the use of Preen. The product is best used outdoors where there is a clear need for weed prevention. Indoor and container plants can usually be managed with regular monitoring and manual weed removal if necessary.

A variety of potted plants on a wooden table.

Comparison Table

FeaturePreen Garden Weed Preventer + Plant FoodMiracle-Gro® Shake ‘N Feed All Purpose Plant Food Plus Weed Preventer1
Primary UseWeed prevention and plant nutritionWeed prevention and plant nutrition
Active Ingredient for Weed PreventionTrifluralinPendimethalin
Nutrient ContentNot specified in detailNPK (Nitrogen, Phosphorus, Potassium) with micronutrients
Application AreasGardens, around trees and shrubs, ornamental bedsGardens, around flowers, vegetables, trees, and shrubs
Weed Control SpectrumPrimarily annual grasses and some broadleaf weedsAnnual grasses and broadleaf weeds
Duration of EffectivenessUp to 3 months per applicationUp to 3 months per application
Application MethodShake applicatorShake applicator
PrecautionsAvoid use in water runoff areas due to potential toxicity to aquatic lifeAvoid application on lawns, near water, or edible plants directly seeded within the last 3 months
Packaging SizesVarious sizes availableVarious sizes available

Product Details

  • Available sizes: 2.25 lb, 4.5 lb, 9 lb jugs
  • Coverage area: Varies depending on size (e.g., 135 sq. ft. for a 4.5 lb jug)
  • Application rate: 4.8 oz. per 10 sq. ft.
  • Active ingredients: Dithiopyr (pre-emergent herbicide), 2,4-D (post-emergent herbicide), NPK fertilizer (10-4-3)


Preen Garden Weed Preventer + Plant Food is designed for dual-purpose use, offering both pre-emergent weed control and nutritional support for plants. Its active ingredient, Trifluralin, targets a broad spectrum of annual grasses and some broadleaf weeds. Preen is suitable for use in ornamental beds, around established trees, and shrubs, and in garden spaces but should be used with caution around water bodies due to its potential aquatic toxicity.

Miracle-Gro® Shake ‘N Feed All Purpose Plant Food Plus Weed Preventer1, on the other hand, combines the benefits of feeding plants with the added advantage of per-emergent weed control using Methamphetamine as the active ingredient. It provides a balanced NPK nutrient supply along with micro nutrients to support overall plant health. This product is formulated for use around flowers, vegetables, trees, and shrubs, with a similar three-month effectiveness period. However, it should not be used on lawns or areas where direct seeding has occurred within the last three months to avoid inhibiting seed germination.

Pros and Cons of Preen Garden Weed Preventer + Plant Food


  • Dual Action: Combines weed prevention with plant nutrition, simplifying garden maintenance by addressing two needs with one product.
  • Easy Application: The granular formula with a convenient shake applicator allows for easy, even distribution over the soil surface.
  • Wide Range of Use: Effective in various garden settings, including ornamental beds, around trees and shrubs, and established garden spaces.
  • Pre-Emergent Weed Control: Effectively prevents the germination of a wide array of annual grasses and some broadleaf weeds, reducing the need for manual weeding.
  • Time-Saving: By preventing weed growth, it saves gardeners considerable time and effort that would otherwise be spent on weeding.
  • Versatile Packaging: Available in various sizes to accommodate different garden dimensions and needs.


  • Not Suitable for All Areas: Cannot be used in areas intended for seed planting or where direct seeding is a common practice, as it inhibits seed germination.
  • Limited Weed Spectrum: While effective against many annual weeds, it does not control perennial weeds that spread through runners or root systems.
  • Environmental Concerns: Potential toxicity to aquatic life necessitates careful use near water bodies to prevent harmful runoff.
  • Reapplication Required: Needs to be reapplied periodically (usually every 3 months) for continuous weed control, which may increase maintenance for some gardeners.
  • Not for Lawn Use: Cannot be used in lawns or grassy areas intended for seeding, as it would prevent grass seed germination.
  • Initial Weed Removal Needed: Requires the removal of existing weeds before application, as it does not kill established weeds.


In conclusion, Preen Garden Weed Preventer + Plant Food offers a practical and efficient solution for gardeners looking to maintain weed-free and nourished garden spaces. Its dual-action formula not only prevents the emergence of new weeds by inhibiting seed germination but also provides essential nutrients to support the health and growth of established plants. This makes it an ideal choice for ornamental beds, around trees, shrubs, and in established garden areas where no direct seeding is planned.


1. What does Preen Garden Weed Preventer + Plant Food do?
Preen Garden Weed Preventer + Plant Food prevents the germination of weed seeds in the soil while providing essential nutrients to your established plants, promoting healthy growth and reducing the need for manual weeding.
2. Can I use Preen in my vegetable garden?
Yes, but with caution. Preen can be used around established vegetables, fruits, and flowers, but it should not be applied in areas where seeds will be directly sown, as it prevents seed germination.
3. How often should I apply Preen to my garden?
For optimal results, Preen should be applied every 3 months during the growing season to maintain an effective barrier against weed seed germination.
4. Will Preen kill my existing plants or flowers?
No, Preen is designed to be safe for use around established plants and flowers. It targets weed seeds in the soil and does not harm existing garden vegetation when used as directed.
5. Can Preen be used in lawn areas?
No, Preen Garden Weed Preventer + Plant Food is not intended for use in lawns or grassy areas where grass seed will be sown, as it will inhibit the germination of grass seeds.
6. Is Preen safe for use around pets and children?
When used according to the label instructions, Preen is safe for use in gardens that pets and children may access. However, it’s always best to keep pets and children off the treated area until the product has been watered in and the area has dried.
7. Can I plant seeds after using Preen?
You should avoid planting seeds in treated areas for several months after application, as Preen prevents seed germination. Check the product label for specific waiting periods before sowing seeds.
8. How does Preen affect the environment?
Preen should be used with environmental considerations in mind, especially around water bodies, due to its potential toxicity to aquatic life. Follow label instructions carefully to minimize environmental impact.
9. What types of weeds does Preen control?
Preen is effective against a wide range of annual weeds, including many common grassy and broadleaf varieties. However, it does not control perennial weeds that propagate through runners or root systems.
10. How do I apply Preen in my garden?
Remove existing weeds, then evenly distribute Preen granules over the soil surface using the built-in applicator. Water the area to activate the product, which then creates a barrier to prevent weed seeds from germinating.

Joel Cunningham
Joel Cunningham
Forestry Author

I'm Joel Cunningham, an expert in pruning and weed management with over a decade of experience. My skills are rooted in formal training and extensive practice, focusing on advanced pruning techniques and efficient weed control. I'm known for my quality work, precision, and deep understanding of plant health and soil dynamics. My contributions extend to educational initiatives where I share sustainable practices and advice, establishing myself as a reliable and authoritative figure in the gardening community.


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