Is it useful to apply herbicides if the grass is very tall?

When using herbicides , you must master the correct time to achieve the best effect. Once the weeds grow very tall, their root systems will also develop accordingly, which undoubtedly increases the difficulty of eradication. So if the grass is very tall, will it be useful to use herbicides? Let’s learn more about it below.

Is it useful to apply herbicides if the grass is very tall?

When grass is tall, using herbicides can still be effective, but special attention may need to be paid to spraying method and agent selection. Tall grass may shade the ground, reducing the contact of the agent with the soil, so it may be necessary to increase the application rate of the agent or use an herbicide with better penetration. For example, glufosinate is a broad-spectrum herbicide that can be absorbed through the stems and leaves and transported to the roots of plants, achieving a weed-killing effect even when weeds are tall.

When is the best time to apply herbicides?

1. Best spraying time

It is usually recommended to spray before 10 am or after 4 pm on a sunny day. Spraying can also be done throughout the day on cloudy days (without rain) to ensure that the herbicide can fully exert its efficacy.

2. Observe weather conditions

Pay close attention to weather conditions before spraying and avoid using herbicides in windy or rainy or snowy weather, as this will reduce the efficacy of the pesticide or cause unnecessary loss of the pesticide. In addition, avoid spraying under high temperature or dewy conditions, as this may reduce the efficacy of the medicine or cause the solution to be diluted.

3. Weed growth stage

The time of herbicide spraying should also be determined according to the growth stage of the weeds. Generally speaking, spraying herbicides is most effective when weeds are in their seedling stage or during their vigorous growth period.

4. Crop growth stage

For example, corn post-emergence weeding should be carried out at the 3-5 leaf stage; soybean post-emergence weeding should be carried out at the 2-3 leaf stage, and weeds should be carried out at the 2-4 leaf stage.

5. Specific operational suggestions

(1) Plan ahead: predict the outbreak period of weeds based on their growth habits and arrange the herbicide application plan in advance.

(2) Follow the instructions: Read the herbicide product label carefully to understand the manufacturer's recommended optimal application time and conditions.

(3) Spraying pesticides in stages: For large plots of land or areas with high weed density, herbicides can be sprayed in batches to avoid excessive one-time application that would affect the efficacy of the pesticide.

In general, if the grass is tall, the effectiveness of using herbicides may be limited, especially if the weeds are mature and setting seeds, then the herbicide may only kill the above-ground parts and not the roots. Of course, it doesn’t mean that it is definitely ineffective. It depends on the actual situation.