It's a warm season weed, and does die down after seed forms. You need to use a pre-emergent before it starts to germinate in the spring, but the effects wear off unless reapplied periodically, and crabgrass seed is very long lived in the ground.

okay. so for these first few years, would you recommend putting a preemergent on as often as fertilizer?

do you recommend a brand? on the lawn care board they were discussing a Lesco 0 0 7, but I can't seem to find it anywhere which makes me wonder if it is not available/allowed in CA.

thank you for your help, I appreciate it!

If you fertilize twice a year, only apply pre-emergent in early spring. I generally prefer to just fertilize lawns once a year, about mid March to early April. The thing is, crabgrass seed lasts years, and if you don't have a healthy thick lawn, remnant seed will still germinate years later. You will need to improve soil conditions, establish a thicker, healthier lawn, and keep an eye out for sprouting crabgrass as it germinates, certainly before it sets seed, and get rid of it. Vigilance pays off over time.

If you fertilize twice a year, only apply pre-emergent in early spring. I generally prefer to just fertilize lawns once a year, about mid March to early April. The thing is, crabgrass seed lasts years, and if you don't have a healthy thick lawn, remnant seed will still germinate years later. You will need to improve soil conditions, establish a thicker, healthier lawn, and keep an eye out for sprouting crabgrass as it germinates, certainly before it sets seed, and get rid of it. Vigilance pays off over time.

Hi Bahia,

This is super helpful, thank you. I did reseed this past fall (aug 15th) and it is growing in nicely. I conditioned the soil before reseeding with baby shampoo and gypsum, and I'm happy with how the water is penetrating.
I have been hand-pulling the crabgrass as often as I can, and have filled up quite a few buckets ---
will the new grass grow over the existing roots that I couldn't pull up?

thank you for your help --- I think I'm on the right track, I just wanted to make sure! it looks like it will take a good year or so to see the results I'm looking for, is that correct?

Due to the drought, I'm only watering once a week for about 20 minutes, and so far our lawn looks the best which worries me that the neighborhood water police are going to think I'm watering much more often than I really am!

It is the truth that green lawns take a lot of water! Tough times for lawn fans, I only do small ones anymore, if at all. Put in many more with Dymondia or Dwarf Mondow Grass. Only a third the water, still walkable, lush let drought tolerant.