Weeds will always find a way! When you’ve spent time preparing a new flower bed or border, digging deep to remove hidden roots and seeds, it can be disheartening to see weeds pop up in spring despite your best efforts.
Even if you sieved your soil, weed seeds can be blown in on the wind or dropped by birds, and weeds that spread via underground rhizomes can creep in making a surprising appearance.
But there are ways to stop some weeds from showing up, specifically two methods of pre-emergent control:
- Chemical control using a pre-emergent herbicide.
- Physically blocking the light needed for weed seed germination.
Pre-emergent Herbicides
Pre-emergent herbicides are residual herbicides. This means they work by creating a barrier in the soil that will kill weeds as they germinate. They can work for up to five months.
Pre-emergent herbicides have no effect on weed seeds that have already germinated but will work well just before germination – to last all the way through the main growing season.
It is important to apply these herbicides before weed seeds are likely to germinate – typically this is early spring for summer annual weeds, or late summer / early autumn for winter annual weeds.
However, for weeds that are active or starting to germinate in the autumn and winter months, use a product like Gem Granules.
This pre-emergent herbicide uses the active ingredient propyzamide which works best in cool, moist soil conditions and is ideal for using between October and January.
As they work by killing emerging seeds, don’t apply pre-emergent herbicides in any areas where you intend on planting grass, vegetables or flower seeds.
Non-chemical Methods
The only non-chemical way to prevent weed seeds emerging is to block the light they will need to put on growth – once they emerge from the soil.
To block the light, use a thick layer of mulch such as shredded bark, leaves, straw, compost or gravel and spread it over the target area. Make sure your mulch is at least 3” thick.
You could also use inorganic mulch such as heavy-duty weed suppression fabric. These membranes can help suppress weed emergence while allowing water and nutrients to penetrate the soil.
Questions about preventing weeds from emerging? Get in touch with our specialist teams today.
This blog post was written in consultation with Dave Rowsell
Dave Rowsell
Dave Rowsell is Agrigem’s Account Manager in charge of leisure and holiday park sites. With a strong background in the landscape supplies sector, Dave brings deep experience of grounds maintenance, facilities management and landscape contracting to bear when meeting the needs of leisure and holiday park customers.
Joining Agrigem in 2022, Dave has built a reputation for great service and is a trusted source of advice when it comes to product and process knowledge – ensuring holiday parks have the right products at the right time, together with the right knowledge and skills to manage an effective grounds maintenance programme.
Article Notes:
- Use plant protection products safely. Always read the label and product information before use. For label and safety information, refer to the manufacturer’s website.
- Only certified users may apply professional plant protection products. Find out more about safe use of pesticides here.
