6/14/19

How Does Mulching in Large Ornamental Production Containers Compare with Preemergent Herbicides?



Season long weed control in large containers that may take six months to a year to finish can be very challenging.  Preventing weed emergence and seeding is critical to maintaining a clean crop and reducing costs.   

We wondered if we could spread a relatively cheap biological mulch over the top of large production containers to reduce weed growth relative to spraying or applying a preemergent herbicide.  We also considered an addition of a tackifier which is a glue to hold down mulch particles for better weed control.

Dr. Chris Marble of UF/IFAS Mid-Florida Research and Education Center and I applied for and received a USDA Southern Sustainable Research and Education On-farm Grant to test the idea.

At four locations and multiple crops, we tested an assortment of mulches:  pinebark, shredded wood, paper slurry, pinebark with paper slurry, sawdust, and we tested with and without the tackifier on all those mulches.  In addition, we included a plastic mulch; the same as vegetable or strawberry growers use. We also included no mulch and a preergent herbicide as controls to see differences.

After a couple of years of research we learned a few things.  All mulches stopped weeds from germinating from the surface soil in the pot early after application.  The more successful mulches over time prevented blown in weed seeds from finding a good spot to become hydrated and gain a foothold on the surface. Plastic mulch was the best followed by large pine bark.

Tackifier had no effect on the mulch performance.

Here is a video of the research that summarizes the work we were able to accomplish.
https://drive.google.com/open?id=1AGjuMfqFqhpF667ZPPmOuKH9oqmDJpvR

For a poster style summary you can click here:  https://drive.google.com/open?id=1nPp45rOSFK61ShBU_JwE-VEbR813uA0F

I would like to give a special thanks to Greg Shiver at J&R Nursery and Vincent Tort at Sun City Tree Farm for their on-farm help and USDA SSARE for the funding.