Nobody able to help ?

Looks like what most of the spring lawns usually look like at this time of spring around here.

OK I hope it will come back and get even

Where do you live?

When was the last time you fertilized and what was the situation with the lawn at the time? Had it stopped growing or was it still growing?

I fertilized yesterday and before that like an year ago

It's pretty important to know where you live. If you live in Phoenix the reasons are going to be different than if you live in Winnipeg.

Ideally grass needs to be fed twice a year with one application in late spring and two applications in the fall. The fall applications should go on in very early fall (after the summer heat breaks) and very late fall (after the grass stops growing but before it freezes).

I am in Toronto, sorry forgot to mention that

I was hoping it was in the North. Closer to Winnipeg than Phoenix I guess ;-)

I'm in San Antonio, but I lived in Dayton for 18 months going to school. What you have looks like damage from snow. I believe they call it 'snow mold.' When you seeded was it pure fescue seed or a mix of fescue, rye, and Kentucky bluegrass? If you have a bit of KBG, then you have a chance of recovery this season as the KBG will spread. If you have only fescue and/or rye, then those spots will not spread, so they will last throughout the season. You could try scratching the surface of the yellow spots and seeding with the exact same seed that you used previously. I believe you are north enough that crabgrass would not be a problem, but there may be other weedy grasses that might take hold while you are waiting for the grass seed to germinate and take hold. If you know that crabgrass is an issue in your area, you could try the seeding and know that you might be disappointed in July when the crabgrass has taken over, or you might get lucky and not have the problem. If you sit it out without doing any seeding, then, then you can seed in the late summer, which is about August (late August?) for you. If your temps remain in the 70/80s in the summer, you might try seeding in the summer. Generally, seeding now runs the risk of crabgrass, and seeding in the summer is a problem with the heat.

While we're talking, what is your watering schedule? How often and for how long do you water?

Yes it is blue grass with some small amounts of something else as per the Scott's bag.

Ok I will wait to see what is happening.

Watering is mostly in July/August, the drier months here. I learned on this forum that it is better to water longer times and less frequently so I will try that (for deeper roots). I used to water 30 min every other day if I remember correctly

You should be good to go for the season. You just fertilized. I'm assuming you did not use an organic fertilizer. You might consider using an organic fertilizer toward the end of May to supplement the fertilizer you just used. Organic and chemical fertilizers do not interact and can be applied the same day at the full rate on the bag, so using an organic again in a month will not hurt anything and will help charge the soil for the summer.

My favorite organic fertilizer is alfalfa pellets, but my understanding is that soybean meal might be available to you for a reasonable price. You could call...

Davis Feed & Farm Supply in Caledon

Feed it Forward on Dundas St W

Queensville Farm Supply Ltd in East Gwillimbury

...to get prices and availability for 20 kilo bags of either product. The application rate is 15 pounds per 1,000 square feet or 7 kilos per 100 square meter. After you apply you can water to wash the stuff off the grass and down to the soil. Rain does the same thing.