Is it a good idea to treat soil with Ronstar granulars before laying a sod lawn?

tskm – posted 02 June 2007 12:51

I am wondering if it is a good idea to apply Ronstar granular preemergent herbicide to bare clay soil before laying sod. One source (i.e.,a landscape contractor) have told me that it will not interfer with the establishment of the new sod (90% tall fescue & 10% Kentucky bluegrass) and another (i.e, the folks at the sod farm where I will be purchasing the sod) advise against it. You would think that both sources should agree on this–but they don’t. Maybe the sod farm person is just doing a CYA???So, now I am trying to hear from those folks that have actually used done it, and learn if they had any problems. Thanks in advance for any information you have on this.

cohiba – posted 02 June 2007 13:40

I would not use it. I feel that it would not kill the turf but will inhibit root growth. Which is what you need after laying the sod. The reason for this is that Ronstar is a root pruner. It attacks new roots of young plants, thereby killing the plant. It cannot tell the difference between a grass root and a weed root.

My 2 cents……….

seed – posted 02 June 2007 17:33

It seems totally unnecessary to place preemergence herbicide underneath the sod, because nothing should be able to germinate through the sod. Phil

tskm – posted 02 June 2007 19:56

Thank you both for your replies.

Seed, I’ve laid some clean sod about 5 years ago, and had weeds come up though it. So it can happen.

seed – posted 18 June 2007 22:05

If weeds are coming through the sod (versus from the sod) they are most likely coming from vegetative propagules underneath the sod, rhizomes, corms, nutlets, and not from seed. So there would be nothing that you could do about them until they pop through. If they were coming from seed, then preemergence herbicide would help, but there are very few seeds that are large enough to be able to germinate and come through sod.

Phil