Spurge is a common, low-growing weed that often takes hold in lawns, garden beds, and pavement cracks, spreading rapidly due to its high seed production. Gardeners frequently seek natural, non-synthetic solutions to control this persistent plant, leading many to wonder about household products. Whether common vinegar can effectively eliminate spurge depends entirely on the strength of the vinegar used and the size of the weed being treated.
How Acetic Acid Works as a Herbicide
The active ingredient in vinegar is acetic acid. This organic compound functions as a contact herbicide, meaning it only damages the plant parts it touches directly and is not translocated to the roots like systemic herbicides.
Acetic acid works by rapidly drawing moisture out of the plant’s cells, a process known as desiccation. This action immediately disrupts the cellular structure of the foliage, causing the plant tissues to turn brown and wilt, essentially “burning” the leaf surface. Visible damage often appears within hours of application.
Because this mechanism targets the surface tissue, acetic acid is classified as a non-selective herbicide. It cannot distinguish between the spurge weed and desirable turfgrass or ornamental plants. Any greenery it contacts will suffer tissue damage, which is a significant factor to consider before application.
Vinegar’s Effectiveness Against Spurge
The success of using vinegar against spurge is directly related to the concentration of acetic acid. Standard household white vinegar contains approximately 5% acetic acid, which is often insufficient for comprehensive weed control. While this lower concentration may cause the top growth of very young, tender spurge seedlings to shrivel, it rarely penetrates deep enough to kill the root system of established plants.
Spurge varieties like Prostrate Spurge have robust taproots that allow them to quickly recover if only the top foliage is scorched. The weed will typically regrow from the surviving root, necessitating repeated applications. For reliable control, especially against established spurge, a much higher concentration is necessary.
Horticultural vinegar, sold specifically as an herbicide, contains between 10% and 20% acetic acid. This industrial-strength concentration is considerably more effective at killing the entire plant, including the root structure, especially when the spurge is still small and actively growing. Research shows that concentrations of 20% acetic acid significantly improve the kill rate compared to the 5% variety. Treating the spurge when it is very young, ideally with only one or two sets of leaves, maximizes the chance of a complete kill.
Safe Application and Formulation Guidelines
When applying vinegar to spurge, target only the weed itself to minimize damage to surrounding plants. The best time for application is on a warm, sunny day, as the heat assists the desiccation process and helps the acetic acid work faster. Spray the entire weed until the foliage is thoroughly saturated, ensuring good coverage of the leaves and stems.
To increase effectiveness, many gardeners add liquid dish soap to the vinegar solution. The soap acts as a surfactant, breaking the surface tension and allowing the mixture to stick better to the waxy surface of the spurge leaves. A typical ratio involves adding a tablespoon of soap to a gallon of vinegar.
Using horticultural vinegar requires serious safety precautions due to its high acid content. Concentrations greater than 10% can cause severe skin burns and permanent eye damage. Users must wear protective gear, including chemical-resistant gloves, protective eyewear, and long sleeves, during mixing and application. Because vinegar is non-selective, be careful of overspray or drift, which can injure or kill surrounding turf and garden plants.
Alternative Methods for Spurge Control
Other methods can provide effective spurge control. Mechanical removal, such as hand-pulling, is highly effective for small infestations, but the entire taproot must be removed to prevent regrowth. Hand-pulling should be done before the plant sets seed, as a single spurge plant can produce hundreds of seeds in a season.
Prevention is an excellent long-term strategy, achieved by maintaining a dense, healthy lawn that crowds out the weed. Applying a layer of landscape fabric or a thick layer of mulch in garden beds blocks sunlight, which suppresses spurge germination.
For moderate or severe infestations, selective chemical post-emergent herbicides targeting broadleaf weeds in turfgrass are available. These products can control spurge without harming the surrounding lawn, provided the label instructions are followed carefully. Pre-emergent herbicides applied in the early spring, before the soil temperature reaches 75°F, can also create a barrier that stops the spurge seeds from sprouting in the first place.