I would wait until it is 95% dead before mowing. Reason - the dead stuff will mow up pretty easy. When you come to a still-live patch, that mower will bog like there is no tomorrow. Ran into this Tuesday. I think you can do the second ap of Roundup as soon as you can tell what is died or is on its way to being dead and what you missed. I could have done my second ap 5 days after the first once I saw what I had missed but I waited until 7 days after due to time conflicts. And for a second ap, you only need to hit the areas you missed, not the whole yard again.

re: Tomatoes-- How long before last frost date should they be Winter sown? Peppers and eggplant would go out at that time also, I assume. I have read through the WS site and the forum here, but it is hard for me to tell because most WSers seem to live in cooler zones.

daisy - Thanks. I have a spot I think they'll like, where I can keep an eye on them. If I looked hard enough, I could probably find some growing nearby. I tried that last year, and thought I had some. But when I went to collect it, it didn't sting. So wrong weed. I don't want them to take over, so I'll be cutting them back regularly. I want to make sure I have a way to remove them in the future though, before I plant. Someone posted a while back that they would eventually give up if I kept mowing them.

Do you know about when the average last frost date is? That's a pretty good guide for when to transplant seedlings that like warm weather - tomatoes, peppers (though they do well in the cooler fall too), eggplant, summer and winter squash, cucumbers, etc. Soil temp is helpful to know too. You can stick a meat thermometer into the soil to get that. Different vegs like different temps. When you seed packages say "as soon as the ground can be worked" it means it. If you aren't expecting a lot of rain or unusually cold temps, and you squeeze a fist full of soil together and have it crumble apart, the soil is ready. Peas, tatsoi, bok choi, spinach and other seeds like cool ground. I plant my peas when the forsythia bloom. Some of the cool weather transplants are broccoli, cabbage and kale. I try to get my warm plants in the ground when they're six weeks old. Their roots aren't so big and compact that they're disturbed much. It reduces something called transplant shock. I try to get my cool plants in the ground when they're around five weeks old. If you have a forecast for unexpected frost or even snow you can cover the seedlings with a sheet to give them a little protection.