I applied a general herbicide and waited a week. Then I put in new grass plugs 5 weeks ago. Since then I have been adding a tray a week. Starting 2 weeks ago, plugs are slowly losing vitality. Leaves are turning brown. A few plugs are practically gone.

WATER: Here in Florida it is still summer. I kept the plugs well watered. It also rains once a week.

FERTILIZER: I applied weed and feed (with post- and pre-emergent herbicide) between the plugs. I also applied 6-6-6 to the plugs, either in the hole or after. I also sprinkled no-burn nitrogen.

PESTICIDE: Just in case the browning is caused by bugs, I spread a pesticide yesterday.

What did I do wrong? I can eliminate lack of water and lack of fertilizer. I suspect too much water, too much fertilizer, or a disease/bug.

EDIT: About 500 sq feet area. Many grass plugs are still green, very healthy. Abut 1/2 of the plugs are affected.

 

Your description of your timeline is not clear. When exactly did you apply herbicide and when did you plant plugs?

What herbicide did you use? There is no "general" herbicide. Each chemical or product has it's own properties and restrictions on planting.

The fertilizer you mentioned. Is that the "general" herbicide you mentioned or is it in addition to the other herbicide? Exactly what product did you apply. There are many different brands and formulations so what you applied can matter.

 

Glyphosphate 41% herbicide diluted to 0.5%. Made by AgriSolutions Cornerstone. August last week.

Grass plugs were planted with 6-6-6 from Lowes. Don't know brand name. Bag was thrown away. September first week. More than 1/2 of grass plugs were planted this week.

More grass plugs are planted about 1 tray a week until yesterday.

Bayer Advanced 3-in-1 weed and feed for Florida grass. Sprinkled to bare spots between grass plugs. Applied September second week.

Milorganite non-burning fertilizer from Lowes. Sprinkled to runners. September 3rd week.

Pesticide applied yesterday.

 

The glyphosate should cause no problem as long as it was applied before you planted the plugs.

Can you post a link to the weed and feed you used. I couldn't find a product for "Florida" grass when I searched. They do have a product for southern lawns. What grass are you planting? So far you've only said "plugs" but centipede can be planted by plugs and is not compatible with the Bayer 3 in 1 for southern lawns that I found.

 

https://www.walmart.com/ip/Bayer-Adv...gaAvH5EALw_wcB

This is what I bought. I just says southern lawns. Where I live, St. Augustine is the most common grass. Plugs are St. Augustine Palmetto, the shade tolerant kind of St. Augustine.

You seem to suspect the herbicide part of weed and feed. If so, it should not affect new plugs, correct? I was more concerned about excessive fertiizer, which would affect new plugs, too.

A related question. I have pre-emergent herbicide. Can I apply it at any time on any grass?

 

You have me confused with all the chemicals you've applied. Were I to take over for you, I'd be stopping their use and just ensuring adequate watering to see if the grass recovers.

 

Read the labels on the products you are using

 

Doing nothing except watering makes sense.

 

Yes, less is better. Generally herbicides are not great for plants. Even if a herbicide says it kills one type of plant it often can injure others. If applied at the proper rate herbicides only mildly hurt non-targeted plants. If you apply too much or too often or apply to new sprouts or seedlings it can have more serious affect.

 

After doing nothing except watering and with the help of weather (not scorching any more), my lawn is recovering. Leaves are green and runners are wild. If this continues another 4-6 weeks, my lawn will be about 80-90% covered. Thank you.