Preen is a widely recognized pre-emergent weed preventer used by gardeners to manage weeds. The term ‘cradle root’ refers to concerns about safely applying such products around established plant roots. This article focuses on effective and safe Preen application, targeting weed seeds without harming your garden’s existing plants. It offers a proactive approach to weed control, saving time and effort later.
Understanding Preen Weed Preventer
Preen is a pre-emergent herbicide, acting on weed seeds before they sprout. It creates a chemical barrier in the soil’s uppermost layer. When weed seeds germinate and attempt to grow through this treated layer, their cellular division is disrupted, preventing them from developing into mature plants.
This means Preen does not kill existing weeds; it stops new ones from emerging. Its effectiveness relies on application before weed seeds sprout, typically in early spring or fall. The active ingredients often include trifluralin or pendimethalin, which interfere with root and shoot development in germinating seeds. This preventative action is key to maintaining a weed-free garden throughout the growing season.
Safe Application Around Plant Roots
Safe application of Preen around established plants requires careful attention to protect their root systems. Apply to dry foliage to prevent granules from sticking to leaves, which could lead to burning. After spreading granules evenly, a light watering is crucial to activate the chemical barrier in the soil, moving active ingredients into the top layer to prevent weed germination.
Near established plants, distribute granules around the plant’s drip line, not directly on the crown or main stem. Maintain a distance of a few inches from the immediate base to prevent direct contact with sensitive plant tissues. This ensures the product primarily affects shallow-rooted weed seeds while protecting the deeper, established root systems of desired plants.
Timing and Plant Compatibility
Optimal timing for Preen application is early spring before weed seeds germinate, ideally when soil temperatures consistently reach 50-60 degrees Fahrenheit. A second application can be beneficial in late summer or early fall to prevent cool-season weeds. Apply when the ground is not frozen to allow the product to create its necessary soil barrier.
Preen is generally safe for many established plants, including most perennials, shrubs, and trees. However, do not use it where you plan to sow desirable seeds, as it will inhibit their germination. Avoid applying Preen near newly transplanted seedlings or very young plants, as their root systems are still developing and can be highly sensitive. Specific product labels often list incompatible plants, such as certain vegetables or annuals grown directly from seed.
Avoiding Common Application Errors
Several common errors can reduce Preen’s effectiveness or harm desirable plants. Over-application is a frequent mistake, leading to a concentrated barrier that may inhibit sensitive plant root growth or cause runoff. Always follow the recommended application rates on the product label to ensure proper coverage. Applying Preen to wet foliage is another error, as granules can stick to leaves, potentially causing leaf burn or discoloration. It is also important to water in the product shortly after application; failing to do so prevents the necessary chemical barrier from forming.