Applying fall herbicides, at the end of harvest, can make a lot of sense in terms of reducing your spring/summer workload and getting ahead of perennial weed species. The first rains will deliver an explosion of new weeds that can actually grow inches overnight, as sustained soil moisture near the surface results in germination and emergence of the weeds. The objective of fall herbicide application is to gain longer-term control of weeds and reduce the amount of weed seed set in the spring.
Now, when plants are stressed from lack of moisture in the summer, the cuticle of their leaves will thicken in order to reduce moisture loss. This cuticle toughening reduces the level of penetration and the metabolization of herbicides, requiring more applications. The leaves of the weed will continue to stay thick and waxy even if it finally rains. However, after rain in the fall new leaves emerge on established plants, allowing better penetration and greater metabolization of the herbicide.
In addition, cooler temperatures in the fall trigger the movement of nutrient reserves down to the root or storage structures of perennial plants like Johnson Grass, to build up reserves for growth in the following season. A fall herbicide application takes advantage of this increased nutrient flow to the roots, increasing the amount of active ingredients reaching the root zone.
Spraying for weeds any time between now and Thanksgiving or even later has advantages. Our recommendation is to wait for rain and the additional weed emergence before applying any herbicide. The risk in this is that the weather turns wet and stays wet, making it difficult to apply herbicide. However, the objective here is to suppress weed growth in the fall, which will hopefully lead to fewer post-emergent applications during the following summer growth season. In addition, fall application of herbicides can control late germinating weeds like chickweed.
Andaman Ag is the master distributor in California of the organic herbicide Weed Slayer. Weed Slayer is systemic, penetrating the plant and killing the root ball for extended control. Given its organic structure, it doesn’t kill the microbiology in the soil or remain as a residue impacting future plant growth. This advantage allows for the planting of a cover crop following an application of Weed Slayer without impacting the cover crop’s germination and growth. It’s also an opportunity to trade a less desirable ground cover for a more desirable ground cover like a broad cover crop.
Weed Slayer is an innovative, non-selective, broad-spectrum, organic-listed herbicide providing both organic and conventional growers an alternative to other, more harmful herbicides.
(Source: Andaman-AG)
Andaman-AG products can be purchased through …
Earthworm Organics Corp.
Vermigrow™
PO Box 223
Thermal, CA 92274
Office: 760-774-1632
[email protected]
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