Redoing a lawn: Pre-emergence weed killer?

[Sackett2]

Now that i have the equipment, (Except the tiller, thats next) I'm thinking of replanting my lawn this fall. I have no problem with the basics of tilling and leveling; but someone in a prior post mentioned something about "Pre-emergence weed killer?" What is that and how when do you apply it. Also, could this be used in the garden after growing season? The amount of weeds in the garden the last several years is bad, and with the new tractor we are going to give the soil a workout before next years growing season

[RonMar]

Originally Posted by Sackett2

Now that i have the equipment, (Except the tiller, thats next) I'm thinking of replanting my lawn this fall. I have no problem with the basics of tilling and leveling; but someone in a prior post mentioned something about "Pre-emergence weed killer?" What is that and how when do you apply it. Also, could this be used in the garden after growing season? The amount of weeds in the garden the last several years is bad, and with the new tractor we are going to give the soil a workout before next years growing season

Well there is probably some way to do it, but most chemical weed killers that I have dealt with say to keep it away from new seed and young lawns. You could possibly use some roundup to take care of any weeds in the area before you lay down the new seed, but there is a period you will have to wait to plant to allow the roundup in the soil to break down. If you have torn up the ground for the seed, you have most likley disturbed the weeds as well which will retard their growth a little. I would probably plant the grass, then use a spray weed be gone after the new grass is established... I think that even if you have used something to zap the weeds, there will still be more after the grass emerges anyway, and you are going to have to control those at that time anyway. I have planted a few areas this summer and this approach has worked pretty well for me so far. In fact, i need to go spray some weedbegone today

Good luck on your lawn...

[ray66v]

Products like Preen are good for gardens and driveways to keep weeds down. You can use it in the garden where you put plants right away, after a few weeks were you put seeds.

You really have a tough enough time getting a lawn established as it is. Using a peremergergent is going to work against you as you may want to reseed and over seed areas that do not come in thick. Unless you have a ton of money for seed, and can really sow it thick right off the bat, I would only spot treat weeds for the first year or two, and let it thicken on its own.

Besides it is pretty expensive.

[Sackett2]

The lawn overall is easy, but the garden, thanks for the heads up on "preen" We have "round-up'ed" in the fall and spring for it, but the volume of weeds is amazing. was looking at alternative ways of attacking them there critters.
Thanks

[dqdave1]

I think roundup does not stay in the ground. It kills the weeds by blocking their ability to photosynethisis which kills them. Anything planted after it is applied will not be harmed.

[ToadHill]

Per emergent products stop seeds from germinating. If you put it down and plant the lawn, the grass seed won't germinate and you'll have a mud pit.

[SCOOBY14B]

Pre-emergents keep a plant from germinating. This goes for grass or weeds. Post emergents kill weeds after they have germinated. Glyphosate (ie Round-up) is a non-selective herbacide that kills just about everything (minus Kudzo, poison ivy/oak, etc). You can spray Glyphosate and seed the same day. It will not hard any seedlings. It becomes dormant/ inneffective when contact with the ground. That is not to say you can spray it hap hazardly as it does remain in the soil and depending on who you ask can become a toxin, but will not harm your turf.

[forester2]

Do NOT use a preemergent weed control in doing a new lawn except Tupersan with is made specifically for new seedings. Regular crabgrass controls and products like PREEN which has Treflan will do the same thing to grass seed as it does to weed seeds in a garden; kill them when they emerge. Spraying old lawn with Roundup or other glysophate products (Roundup is off patent and many other companies are making glysophate products) is a great idea; it will kill all the old grass and weeds and give you a fresh start. You can even seed before the old grass has died since Roundup has no soil activity; kills only what it contacts.